Low Yield

What type RBCs can be transfused to an A2 person with anti-A1? A. A only B. A or O C. B D. AB

B A person in need of an RBC transfusion who is an A2 with anti-A1 can be transfused A or O cells because the anti-A1 is typically only reactive at room temperature. Harr, Robert R. Medical Laboratory Science Review (Page 127). F.A. Davis Company. Kindle Edition.

The peroxidase stain is useful in differentiating between which cells? Lymphocytic and granulocytic cells Monoblastic and myeloblastic cells Leukemoid reaction and myelocytic leukemia Eosinophils and neutrophils

Lymphocytic and granulocytic cells Peroxidase stain is an enzymatic stain based on the principle that peroxidase granules in some neutrophils and in eosinophils will stain positive. Lymphocytes stain negative with peroxidase stains. Question Difficulty: Level 7

On sheep blood agar, Haemophilus influenzae may exhibit satellitism around all of the following bacteria, EXCEPT: Pseudomonas spp. Neisseria spp. Staphylococcus spp. Streptococcus pneumoniae

Pseudomonas spp. The correct answer is Pseudomonas spp. Neisseria, Staphylococcus, and Streptococcus pneumoniae produce enough V factor to allow H. influenzae to grow on blood agar near their colonies; however, Pseudomonas does not. This property is utilized in the "satellite test" technique whereby minute colonies of Haemophilus are seen in the hemolytic zone surrounding a streak of S. aureus on sheep blood agar, providing a presumptive identification of Haemophilus. Question Difficulty: Level 7

Normal cells Normal red cells are uniformly shaped, have diameter of approximately 7.5 µm, and with 2-3 mm of round central pallor. A normal sized red cell (MCV = 80-100fL) would appear about the same size as the nucleus of a small lymphocyte. Microcytes have smaller diameter and would appear smaller than the nucleus of the lymphocyte in this image. Macrocytes have larger diameter. Hypochromic cells have larger central pallor. Question Difficulty: Level 5

The erythrocytes seen in this illustration are indicative of: Normal cells Microcytic cells Macrocytic cells Hypochromic cells

A unit of whole blood is collected at 10:00 a.m. and stored at 20-24 degrees Celsius. What is the last hour platelet concentrates may be made from this unit? A. 4:00 p.m. B. 6:00 p.m. C. 7:00 p.m. D. 8:00 p.m.

B Platelets preparation from whole blood must be done within 8 hours of collection. Harr, Robert R. Medical Laboratory Science Review (Page 149). F.A. Davis Company. Kindle Edition.

Which of the following organisms is indole negative? Escherichia coli Klebsiella oxytoca Chryseobacterium indologenes Capnocytophaga canimorsus

Capnocytophaga canimorsus None of the Capnocytophaga species produce indole. Both Escherichia coli and Klebsiella oxytoca are strong indole producers. Chryseobacterium indologenes is a weak indole producer. Question Difficulty: Level 7

What detection method releases of light energy as the product of a chemical reaction? Chemiluminescence Radioactivity Fluorescence Electrophoresis

Chemiluminescence Chemiluminescence is the detection method that releases of light energy as the product of a chemical reaction. Radioactivity uses a scintillation counter to detect decay. Fluorescence is a detection method where molecules emit light at a longer wavelength when excited at a shorter wavelength and can be stained as well as labeled. Electrophoresis is a detection method where movement in a gel matrix is caused by an electrical field. Question Difficulty: Level 7

Which potent inhibitor of platelet aggregation is released by endothelial cells? Epinephrine Prostacyclin Ristocetin Thromboxane A2

Prostacyclin Prostacyclin is produced by endothelial cells and prevents formation of the platelet plug involved in primary hemostasis by preventing platelet activation and aggregation as well as inducing vasodilation. Epinephrine (agonist used in platelet aggregation studies), ristocetin (agonist used in platelet aggregation studies), and thromboxane A2 (platelet activator) are not produced by the endothelial cells. Question Difficulty: Level 7

A2B POS The patient forward types as group AB, but the back type suggests that he is group B. A discrepancy is noted between the forward and back types. One reason for this discrepancy is a group A2B patient producing anti-A1. Because there is a discrepancy between the forward and back types, AB POS is not the best answer. An AB POS patient would have a non-reactive back type. A POS is not the best answer because the forward type shows both A and B antigens are present on the patient's red cells. While the back type presents as a group B patient the forward type does not match this interpretation, making B POS an incorrect answer. Question Difficulty: Level 9

You perform a gel ABO/Rh test on a 45-year-old male patient and you obtain the following results. What could be the Type/Rh of this patient? AB POS A POS B POS A2B POS

A prolonged APTT and PT are corrected when mixed with normal plasma. Which factor is most likely deficient? A. VIII B. V C. XI D. IX

B Factor V (common pathway factor) deficiency is most likely suspected, because both the PT and APTT are prolonged, and both are corrected when mixed with normal plasma. Harr, Robert R. Medical Laboratory Science Review (Page 56). F.A. Davis Company. Kindle Edition.

All of the following viruses have RNA as their nucleic acid content, EXCEPT: Togavirus Coronavirus Metapneumovirus Adenovirus

Adenovirus The correct answer is Adenovirus. Adenovirus is a DNA virus that is found in the pharynx and feces. It can cause a wide range of infections such as otitis, pharyngitis, pneumonia, hepatitis, and gastroenteritis. Children are the most common group affected. Togavirus, Coronavirus, and Metapneumovirus are all RNA viruses. Question Difficulty: Level 7

Cold agglutinin disease (CAD) is most often associated with which antibody? Anti-D Anti-M Autoanti-I Autoanti-i

Autoanti-I In CAD, patients may have a history of mild anemia, Mycoplasma pneumoniae infection, or infectious mononucleosis. The autoantibody specificity in CAD is most often autoanti-I and less commonly autoanti-i. Question Difficulty: Level 7

Spiral (spirochetes) Section A of the illustration shows spiral shaped organisms consistent with spirochete organisms. Bacilli are shown in illustration F. Cocci are shown in illustration B. Curved bacilli consistent with Vibrios are shown in illustration D. Question Difficulty: Level 3

Please see the image. Which illustration corresponds with the classification of bacteria seen in section A? Bacilli Spiral (spirochetes) Cocci Curved bacilli (Vibrios)

Echinocytes When echinocytes (burr cells) are predominant, as presented in this photomicrograph, an artifact of smear preparation should be considered. Artifactual burr cells, called crenated red blood cells, occur due to an increased pH (alkaline environment), storing blood at 4°C, slow drying or drying in a humid environment, and excess EDTA due to an underfilled collection tube. If burr cells are still predominant on a new preparation, further investigation of their presence may be necessary. Acanthocytes are not typically seen as artifacts. Stomatocytes and codocytes can be seen as artifacts, but are either not predominant or not present in this photomicrograph. Question Difficulty: Level 5

Which of the following red blood cell morphologies, commonly seen as an artifact, is predominant in the photomicrograph? Acanthocytes Echinocytes Stomatocytes Codocytes

This area is unacceptable for evaluating red blood cell morphology because it is too thin This photomicrograph represents an area of the peripheral blood smear that is too thin for performing a white blood cell differential, as well as evaluating red blood cell, white blood cell, or platelet morphology. The red blood cells appear flat, distorted, and lack central pallor. This is typical of red blood cells in the feathered edge. The white blood cell differential and evaluation of red blood cell, white blood cell, and platelet morphology must be performed in the monolayer, also known as the critical area of the smear. The monolayer is the area of the smear where red blood cells are evenly distributed, barely overlap, and have nice central pallor. The area shown is acceptable for scanning for blast cells, parasites, fibrin strands, and platelet clumps at a low magnification, and omitting this step as part of peripheral blood smear evaluation is a common error in the hematology laboratory. Question Difficulty: Level 6

Which of the following statements regarding the peripheral blood smear shown in the photomicrograph is TRUE? This area is acceptable for performing a manual differential This area is unacceptable for scanning for blast cells, parasites, fibrin strands, and platelet clumps This area is unacceptable for evaluating red blood cell morphology because it is too thin This area is acceptable for evaluating red blood cell morphology

Listeria monocytogenes L. monocytogenes is motile (optimum at room temperature or 25°C), hydrolyzes esculin (black), and gives a positive VP reaction (red). Erysipelothrix rhusiopathiae is negative for all these tests. E. rhusiopathiae may have colony and Gram stain features similar to that of Listeria monocytogenes however, E. rhusiopathiae produces H2S in Kligler and Triple Sugar Iron Agar while L. monocytogenes does not. Corynebacterium spp. and Arcanobacterium haemolyticum are not motile. Question Difficulty: Level 4

Which organism matches the reactions shown? Left tube: Motility agar (note subsurface flare shown by arrows) Middle tube: Esculin hydrolysis (+) Right tube: Voges-Proskauer(VP) (+) Erysipelothrix rhusiopathiae Arcanobacterium haemolyticum Corynebacterium spp. Listeria monocytogenes

SITUATION: A technologist is performing an enzyme assay at 340 nm using a visible-range spectrophotometer. After setting the wavelength and adjusting the readout to zero %T with the light path blocked, a cuvette with deionized water is inserted. With the light path fully open and the 100%T control at maximum, the instrument readout will not rise above 90%T. What is the most appropriate first course of action? A. Replace the source lamp B. Insert a wider cuvette into the light path C. Measure the voltage across the lamp terminals D. Replace the instrument fuse

A Visible spectrophotometers are usually supplied with a tungsten or quartz halogen source lamp. Tungsten lamps produce a continuous range of wavelengths from about 320-2,000 nm. Output increases as wavelength becomes longer peaking at around 1,000 nm, and is poor below 400 nm. As the lamp envelope darkens with age, the amount of light reaching the photodetector at 340 nm becomes insufficient to set the blank reading to 100%T. Quartz halogen lamps produce light from 300 nm through the infrared region. Deuterium or hydrogen lamps produce ultraviolet-rich spectra optimal for ultraviolet (UV) work. Mercury vapor lamps produce a discontinuous spectrum that includes a high output at around 365 nm that is useful for fluorescent applications. Xenon lamps generate a continuous spectrum of fairly uniform intensity from 300-2,000 nm, making them useful for both visible and UV applications. Harr, Robert R. Medical Laboratory Science Review (Page 174). F.A. Davis Company. Kindle Edition.

In most circumstances, when two controls within a run are both greater than +-2s from the mean, what action should be taken first? A. Recalibrate, then repeat controls followed by selected patient samples if quality control is acceptable B. Repeat the controls before taking any corrective action C. Change the reagent lot, then recalibrate D. Prepare fresh standards and recalibrate

A When a 22s rule is broken an SE is present and corrective action is required (repeating just the QC will not correct the problem). If recalibration yields acceptable QC results, both sets of QC results and the corrective action taken are documented in the QC log. If the magnitude of the error is large enough to be medically significant, then all patient samples since the last previously acceptable QC should be repeated. If in question, the magnitude of the error can be evaluated by repeating abnormal patient samples. If the average difference between results before and after recalibration is > 2s, then all samples should be repeated since the last acceptable QC. Harr, Robert R. Medical Laboratory Science Review (Page 227). F.A. Davis Company. Kindle Edition.

A person has a fasting triglyceride level of 240 mg/dL. The physician wishes to know the patient's non-HDL cholesterol level. What cholesterol fractions should be measured? A. Total cholesterol and HDL cholesterol B. Total cholesterol and LDL cholesterol C. HDL cholesterol and LDL cholesterol D. Total cholesterol and chylomicrons

A When the HDL cholesterol is subtracted from the total cholesterol, the result is called the non-HDL cholesterol. This result, the sum of LDL cholesterol and VLDL cholesterol, represents the fraction with atherogenic remnant lipoproteins as well as LDL cholesterol. People who have a fasting triglyceride ≥ 200 mg/dL are at increased risk for coronary artery disease owning to atherogenic VLDL remnants, and the treatment goal is to have a non-HDL cholesterol no more than 30 mg/dL greater than the LDL cholesterol. Harr, Robert R. Medical Laboratory Science Review (Page 262). F.A. Davis Company. Kindle Edition.

Following a 2-week camping trip to the Southwest (US), a 65-year-old male patient was hospitalized with a high fever and an inflammatory swelling of the axilla and groin lymph nodes. Several blood cultures were obtained, resulting in growth of gram-negative rods resembling "closed safety pins." The organism grew on MacConkey's agar showing non-lactose-fermenting colonies. Testing demonstrated a nonmotile rod that was biochemically inert. What is the most likely identification? A. Yersinia pestis B. Klebsiella pneumoniae C. Proteus vulgaris D. Morganella morganii

A Yersinia pestis is the cause of bubonic and pneumonic plague. Bubonic plague causes swelling of the groin lymph nodes (bubos), whereas pneumonic plague involves the lungs. The infection caused by bubonic plague may result in fulminant bacteremia that is usually fatal. The transmission is from rodents (rats, ground squirrels, or prairie dogs) to humans by the bite of fleas (vectors) or by ingestion of contaminated animal tissues. Pneumonic plague is acquired via the airborne route when there is close contact with other pneumonic plague victims. Harr, Robert R. Medical Laboratory Science Review (Page 399). F.A. Davis Company. Kindle Edition.

Your community hospital is considering the addition of a new hematology screening test. The laboratory is asked to calculate the total cost of quality control per new test. Quality control must be performed 3 times per day (every 8 hours). The labor cost per quality control test is $8.95 each. A day's worth of quality control reagent costs $23.62. What is the total quality control cost per new hematology test if 6700 of these new tests are performed each year? The correct answer is highlighted below $2.49 $1.28 $1.46 $2.75

$2.75 In this scenario, the answer can be calculated by first determining the total quality control labor costs and the total consumable costs. 1. If quality control is run 3 times per day, a total of 1095 quality control runs are performed each year. (3 x 365 = 1095) 2. The direct labor cost of $8.95 multiplied by 1095 quality control runs equals $9800.25 per year in quality control direct labor. 3. The hospital pays $23.62 per day on quality control consumables, which equals $8621.30 per year. ($23.62 x 365 = $8621.30) 4. The total quality control costs in a year are equal to $9800.25 + $8621.30 = $18421.55. If 6700 new tests are performed each year, the total quality control cost per new hematology test will be $2.75. ($18421.55/6700 = $2.75) Question Difficulty: Level 7

A manual white blood cell count was performed by the hematology technologist. The cell counts for each of two sides was 38 and 42 respectively. All nine large squares were counted on each side. The dilution for this kit was pre-measured at 1:10. What should the technologist report as the white cell count? 4.8 x 109/L 4.4 x 109/L 0.48 x 109/L 0.44 x 109/L

0.44 x 109/L Calculation: Cells Counted (in this case the average of both sides) X dilution factor (in this case 10) / # of sqaures counted (in this case 9) X 0.1mm (depth of solution) X area of each square (1mm2) So, in this problem: (40 x 10) / (9 x 1mm2 x 0.1mm) = 444.4/mm3 (can be converted to 0.44 x 109/L) Question Difficulty: Level 7

At many hospitals, patients with sickle cell disease are given phenotypically matched units of blood. This policy is often used to help prevent alloimmunization to common RBC antigens in patients who are regularly transfused. A patient who regularly comes to your hospital demonstrates the following phenotype on her RBCs: C antigen positive; E antigen negative; K antigen positive. The patient's doctor requests a single unit of crossmatched packed RBCs. Based on the antigen prevalence indicated below, how many units of ABO compatible packed RBCs will you phenotype to find one to transfuse to this patient? Antigen frequencies C antigen positive: 68% E antigen positive: 22% K antigen positive: 9% 7 units 77 units 4 units 1 unit

1 unit Since the patient is negative for E antigen, the patient is only capable of producing anti-E. Thus, you need to provide units that are negative only for the E antigen. You do not have to provide units that are negative for the C and K antigens. STEP 1: Since 22% of donors are positive for E antigen, 78% are negative for E antigen. 78% expressed as a decimal is 0.78 STEP 2: The reciprocal of 0.78 is calculated as follows (1/0.78) = 1.3 1.3 compatible units should be antigen typed to find a single unit negative for E antigen. Rounding to the closest whole number gives you the correct answer choice of 1. An alternate method to determine the number of units to antigen type is to solve for x using a ratio. In this case the ratio would be: 78/100 = 1/x 78x = 100 x = 1.28 or approximately 1 unit Question Difficulty: Level 9

In blood banking, the Direct Antiglobulin Test (DAT) is used in the investigation of which of the following clinical conditions? 1. Hemolytic Disease of the Fetus and Newborn (HDFN) 2. IgA deficiency 3. Hemolytic Transfusion Reaction (HTR) 4. Zika virus infection 1, 2, 3 1, 3 2, 4 All of the above

1, 3 The DAT test is used to detect in vivo sensitization of RBCs, so is most useful in detecting conditions in which antigen-antibody interactions occur in a patient's body. HDFN and HTR are two such conditions. Investigation of IgA deficiency would not usually include performing a DAT on the patient unless symptoms specifically warranted this test. Zika virus testing is performed on donated units, but infection with this virus would not normally include performing a DAT on the patient. Question Difficulty: Level 9

What is the approximate percentage of individuals in the US who are heterozygous for HFE mutations for hereditary hemochromatosis? 0.05% to 0.10% 1% to 2% 10% to 12% 20% to 25%

10% to 12% Hemochromatosis is a form of iron overload, or accumulation of excess iron. The condition affects the skin, liver, pancreas (traditionally called "bronzed diabetes"), and the heart. Hemochromatosis may be an acquired condition or inherited. In hereditary form of hemochromatosis, a mutation in the HFE gene is the most common cause. Early diagnosis and treatment can prevent these secondary effects of iron overload. Approximately 10% to 12% of individuals in the US are heterozygous for HFE mutations. The most common causative HFE mutation is the homozygous Cys282Tyr (C282Y) mutation. Prevalence is high in white population (homozygote 3-5%) but almost absent in non-white population. In northern Europeans, heterozygosity approaches 13%. Question Difficulty: Level 7

What minimum level of specific resistance (megohms@25o C) is required for a Type I water system: 10.0 5.0 2.0 0.1

10.0 Specific resistance is the resistance in Ohms of a 1 cm long by 1 cm2 cross sectional column of solution. Type I water is the purest, and therefore has the highest resistance. Type II water is used for most routine laboratory determinations, and must have a specific resistance of at least 2.0. Type III water is the least pure; it must have a specific resistance of at least 0.1. Question Difficulty: Level 7

The blood is diluted 1:100 and charged on the hemocytometer counting chambers on both sides. If the average platelet count from a counting chamber in one mm2 (one large square) is 68, what is the calculated platelet count? 680,000/mm3 6,800/mm3 68,000/mm3 34,000/mm3

68,000/mm3 A simple way to calculate platelet counts on the hemocytometer is to multiply the average platelet count between the two sides of the chamber by 1,000. In this case 68 x 1,000 = 68,000 platelets. The longer derivation is as follows: The standard dilution of blood for platelet counts is 1:100; therefore the dilution factor is 100. The volume of diluted blood used is based on the area and depth of the counting area. The area counted is 1 mm2 per side (since we are using the average platelet count, we only use the area of one side) and the depth factor is 10. ((Total number of cells counted x dilution factor x depth factor(mm)) / area in mm2) = platelets per mm3 Note: 103/mm3 = 103/µL = 109/L Question Difficulty: Level 7

A 1:100 dilution of a patient's peripheral blood was made and a total of 136 platelets were counted in 5 squares of the RBC area of a Neubauer-ruled hemocytometer. What is the Platelet count? Note: The volume correction factor is 50 µL. 27 x 103/µL 68 x 103/µL 136 x 103/µL 680 x 103/µL

680 x 103/µL The general formula for calculating cellular elements on a Neubauer hemocytometer is as follows: Count = [(Dilution Factor) x (Total cell count in 5 RBC squares] x (Volume Correction Factor) Count = (100 x 136) x 50 = 680,000 or 680 x 103/ µL Question Difficulty: Level 9

How long are healthy neutrophils expected to reside in the peripheral blood of an adult? 3 days 1 day 7-8 hours 12-14 hours

7-8 hours Neutrophils reside in the peripheral circulation for only 7-8 hours ( approx. 7.5 hours) before entering the tissues and body cavities. This process is called diapedesis. Question Difficulty: Level 8

What is the molarity of H2SO4 (GMW = 98) that has a specific gravity of 1.21 and an assay weight of 68% w/v? 0.84 M 8.4 M 1.68 M 16.8 M

8.4 M molarity = moles of solute liter of solution The specific gravity tells us that 1 ml of the acid solution weighs 1.21 grams, therefore 1 liter (1000 ml) of the acid will weigh 1210 grams. Because the solution is 68 percent H2SO4 by weight, 1210 grams of the solution contains: 1210 grams X 0.68 = 822.8 grams of H2SO4 The gram-formula weight of H2SO4 is 98, therefore, 822.8 grams of solution contain: Moles of H2SO4 = 822.8 grams/98 g/mole = 8.40 moles Since the concentrated sulfuric acid contains 8.40 moles of H2SO4 in 1 liter of solution, its concentration is 8.4 M. Question Difficulty: Level 8

A Gram stain of a urethral discharge from a man showing extracellular and intracellular gram-negative diplococci within segmented neutrophils is a presumptive identification for: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Moraxella (Branhamella) catarrhalis D. Neisseria lactamica

A A Gram stain of urethral discharge (in men only) showing typical gonococcal cells in PMNs should be reported "presumptive N. gonorrhoeae, confirmation to follow." With female patients, the normal vaginal flora contain gram-negative cocci and diplococci resembling gonococci and, therefore, no presumptive identification should be reported for N. gonorrhoeae from the vaginal Gram stain smear. Harr, Robert R. Medical Laboratory Science Review (Page 424). F.A. Davis Company. Kindle Edition.

Which test should be performed when a patient has a reaction to transfused plasma products? A. Immunoglobulin levels B. T-cell count C. Hemoglobin levels D. Red cell enzymes

A A reaction to plasma products may be found in an IgA-deficient person who has formed anti-IgA antibodies. Immunoglobulin levels would aid in this determination. Selective IgA deficiency is the most common immunodeficiency disease and is characterized by serum IgA levels below 5 mg/dL. IgA is usually absent from secretions, but the B-cell count is usually normal. Harr, Robert R. Medical Laboratory Science Review (Page 106). F.A. Davis Company. Kindle Edition.

Which substrate concentration is needed to achieve zero-order conditions? A. Greater than 99 × K m B. [S] = K m C. Less than 10 × K m D. [S] = 0

A A zero-order reaction rate is independent of substrate concentration because there is sufficient substrate to saturate the enzyme. V = V max × [S]/K m + [S] where V = velocity, V max = maximum velocity, [S] = substrate concentration, and K m = substrate concentration required to give 1/2 V max . If [S] >>> K m, then the K m can be ignored. V = V max × [S]/[S] = V max × [S]° or velocity approaches maximum and is independent of substrate concentration. Harr, Robert R. Medical Laboratory Science Review (Page 263). F.A. Davis Company. Kindle Edition.

Gram stain of a smear taken from the periodontal pockets of a 30-year-old man with poor dental hygiene showed sulfur granules containing gram-positive rods (short diphtheroids and some unbranched filaments). Colonies on blood agar resembled "molar teeth" in formation. The most likely organism is: A. Actinomyces israelii B. Propionibacterium acnes C. Staphylococcus intermedius D. Peptostreptococcus anaerobius

A A. israelii is part of the normal flora of the mouth and tonsils but may cause upper or lower respiratory tract infections. The sulfur granules are granular microcolonies with a purulent exudate. Like Nocardia, Actinomyces produces unbranched mycelia and is sometimes (erroneously) considered a fungus. It has also been implicated in pelvic infection associated with intrauterine contraceptive devices (IUDs). Harr, Robert R. Medical Laboratory Science Review (Page 437). F.A. Davis Company. Kindle Edition.

A rapidly growing nonseptate mold produced colonies with a gray surface resembling cotton candy that covered the entire plate. Microscopic examination revealed sporangiophores arising between, not opposite, the rhizoids and producing pear-shaped sporangia. What is the most likely identification? A. Absidia spp. B. Penicillium spp. C. Rhizopus spp. D. Aspergillus spp.

A Absidia spp. are similar to Rhizopus spp. except for the location of rhizoids (rootlike hyphae). The rhizoids of Rhizopus spp. are located at the point where the stolons and sporangiophores meet, whereas those of Absidia spp. arise at a point on the stolon between the rhizoids. Penicillium spp. and Aspergillus spp. do not form rhizoids. Harr, Robert R. Medical Laboratory Science Review (Page 452). F.A. Davis Company. Kindle Edition.

Three blood cultures taken from a 30-year-old cancer patient receiving chemotherapy and admitted with a urinary tract infection grew lactose-negative, motile, gram-negative rods prior to antibiotic therapy. Given the following biochemical reactions, which is the most likely organism? H2 S (TSI) = + Indole = + MR = + VP = Neg Citrate = Neg Urease = + DNase = + Phenylalanine deaminase = + Gelatin hydrolysis = + Ornithine decarboxylase = Neg A. Proteus vulgaris B. Proteus mirabilis C. Serratia marcescens D. Klebsiella pneumoniae

A Although P. mirabilis is more frequently recovered from patients with urinary tract infections, P. vulgaris is commonly recovered from immunosuppressed patients. P. mirabilis is indole negative and ornithine decarboxylase positive but otherwise is very similar to P. vulgaris. Harr, Robert R. Medical Laboratory Science Review (Page 398). F.A. Davis Company. Kindle Edition.

Microsporidial infections can be confirmed using: A. Light microscopy and modified trichrome stains B. Phase contrast microscopy and routine trichrome stains C. Electron microscopy and modified acid-fast stains D. Fluorescence microscopy and hematoxylin stains

A An infection with microsporidia can be confirmed using modified trichrome stains (10X the normal dye content found in routine trichrome stains) and light microscopy. The internal polar tubule will be visible within some of the spores; this will serve as confirmation of the infection. Harr, Robert R. Medical Laboratory Science Review (Page 475). F.A. Davis Company. Kindle Edition.

An isolate of E. coli recovered from the stool of a patient with severe bloody diarrhea should be tested for which sugar before sending it to a reference laboratory for serotyping? A. Sorbitol (fermentation) B. Mannitol (oxidation) C. Raffinose (fermentation) D. Sucrose (fermentation)

A An isolate of E. coli recovered from a stool culture in hemorrhagic colitis can be definitely identified only by serotyping. The isolate is identified as E. coli by the usual biochemical reactions. The strain of E. coli responsible for hemorrhagic colitis is O157:H7 and is usually negative for sorbitol fermentation. Colonies of this strain of E. coli appear colorless on MacConkey agar with sorbitol added. Harr, Robert R. Medical Laboratory Science Review (Page 391). F.A. Davis Company. Kindle Edition.

A patient has an elevated serum T3 and free T4 and undetectable TSH. What is the most likely cause of these results? A. Primary hyperthyroidism B. Secondary hyperthyroidism C. Euthyroid with increased thyroxine-binding proteins D. Euthyroid sick syndrome

A An undetectable TSH with increased T 3 is caused by primary hyperthyroidism (suppression via high free thyroid hormone). In secondary hyperthyroidism, the TSH will be elevated in addition to at least the T 3 . Patients with an increased thyroxine-binding protein level will have an increase in total T 3 but not free T 4 or TSH. Patients with euthyroid sick syndrome usually have a low total T 3 due to deficient conversion of T 4 to T 3 , normal free T 4 , and a normal or slightly elevated TSH. Harr, Robert R. Medical Laboratory Science Review (Page 292). F.A. Davis Company. Kindle Edition.

An elderly woman who cared for several domestic cats was hospitalized with suspected cat-scratch disease (CSD). Blood cultures appeared negative, but a small, slightly curved pleomorphic gram-negative bacillus grew on BHI agar (brain, heart infusion agar with 5% horse or rabbit blood). What is the most likely identification? A. Bartonella spp. B. Brucella spp. C. Kingella spp. D. Haemophilus spp.

A Bartonella spp. are difficult to grow on primary culture media. When CSD is suspected from the patient's history, blood cultures should be smeared and Gram stained. Bartonella spp. are biochemically inert, meaning that they are negative for oxidase, catalase, indole, and urease tests. Therefore, commercial identification systems, DNA amplification for various genes, and indirect immunofluorescence assays are used to identify these organisms. Harr, Robert R. Medical Laboratory Science Review (Page 413). F.A. Davis Company. Kindle Edition.

A 20-year-old horse groomer exhibited a "glanders-like" infection. His history indicated he had suffered several open wounds on his hands 2 weeks before the swelling of his lymph nodes. A gram-negative rod was recovered from a blood culture that grew well on blood and MacConkey agars. Most of the biochemical tests were negative, including the cytochrome oxidase test. What is the most likely identification? A. Burkholderia mallei B. Pseudomonas aeruginosa C. Pseudomonas stutzeri D. Burkholderia pseudomallei

A Burkholderia mallei is rarely transmitted to humans. It is the causative agent of glanders in mules, donkeys, and horses. It is not part of the human skin flora and the most likely transmission to humans is through broken skin. Harr, Robert R. Medical Laboratory Science Review (Page 404). F.A. Davis Company. Kindle Edition.

A 46-year-old dog warden was admitted to the hospital with several puncture bite wounds encountered while wrangling with a stray dog. Culture at 48 hours produced small yellow colonies on 5% sheep blood and chocolate agars in 10% CO2 , but no growth on MacConkey agar. Gram stain showed gram-negative curved, fusiform rods. Colonies were oxidase and catalase positive. What is the most likely identification? A. Capnocytophaga canimorsus B. Francisella tularensis C. Legionella pneumophila D. Pseudomonas aeruginosa

A C. canimorsus are part of the oral flora of dogs. The organisms require at least 5% CO2 for growth and grow slowly on blood and chocolate agars. Colonies can grow in 48 hours if cultured in high CO2 on BHI agar with 5% sheep blood. Harr, Robert R. Medical Laboratory Science Review (Page 414). F.A. Davis Company. Kindle Edition.

A blood agar plate inoculated with sputum from a patient with diabetes mellitus grew very few bacterial flora and a predominance of yeast. Given the following results, what is the most likely identification of the yeast isolate? CORNMEAL TWEEN 80 AGAR Germ tube = Neg Pseudohyphae = + Arthroconidia = Neg Blastoconidia = + (arranged along pseudohyphae) Chlamydospores = Neg A. Candida tropicalis B. Candida kefyr (pseudotropicalis) C. Trichosporon cutaneum D. Geotrichum candidum

A C. tropicalis and C. kefyr (pseudotropicalis) differ in their arrangement of blastoconidia along the pseudohyphae. C. kefyr (pseudotropicalis) forms elongated blastoconidia arranged in parallel clusters that simulate logs in a stream. Trichosporon spp. and Geotrichum spp. form arthroconidia. Harr, Robert R. Medical Laboratory Science Review (Page 449). F.A. Davis Company. Kindle Edition.

A cell population is positive for surface markers CD45, CD3, CD4, and Tdt. Which type of leukocytes are these? A. Lymphocytes B. Granulocytes C. Monocytes D. Early myeloid precursors

A CD45 is a panleukocyte marker and reacts with all white blood cells and precursors. CD3, CD4, and Tdt are markers for T lymphocytes. Typically, a panel of 12 or more antibodies is used to characterize the lineage and maturity of a cell population. The abbreviation CD stands for cluster of differentiation. Monoclonal antibodies with the same CD number recognize the same marker, although the specific moiety they react with may be different. Harr, Robert R. Medical Laboratory Science Review (Page 520). F.A. Davis Company. Kindle Edition.

In which circumstance will the reporting of calculated oxygen saturation of hemoglobin based on PO2, pH, temperature, and hemoglobin be in error? A. Carbon monoxide poisoning B. Diabetic ketoacidosis C. Patient receiving oxygen therapy D. Assisted ventilation for respiratory failure

A CO has about 200 times the affinity as O2 for hemoglobin and will displace O2 from hemoglobin at concentrations that have no significant effect on the PAO2 . Consequently, calculated oxygen saturation will be erroneously high. Other cases in which the calculated O2 Sat should not be used include any hemoglobinopathy that affects oxygen affinity and methemoglobinemia. The other situations above affect the O2 saturation of hemoglobin in a manner that can be predicted by the effect of pH, PO2 , and PCO2 on the oxyhemoglobin dissociation curve. Harr, Robert R. Medical Laboratory Science Review (Page 194). F.A. Davis Company. Kindle Edition.

A whole-blood donor currently on clopidogrel (Plavix) is precluded from donating which product? A. Platelets B. Red blood cells C. FFP D. Cryoprecipitate

A Clopidogrel renders platelets nonfunctional and therefore potential donors on this medication cannot donate platelets. Harr, Robert R. Medical Laboratory Science Review (Page 155). F.A. Davis Company. Kindle Edition.

In real-time PCR, quantitation can be done without standards of known copy number. Relative quantitation (estimated concentration) is possible because: A. Each cycle generates a twofold increase in product B. Each cycle threshold represents a 10-fold increase in product C. The fluorescence of two samples can be compared directly D. Concentration is proportional to fluorescence at the endpoint of the PCR reaction

A Concentration is exponentially related to fluorescence at the start of the PCR reaction, but beyond the early exponential phase, the relationship does not hold. The cycle threshold is in the exponential phase of amplification, which is why the Ct is used for quantification. Since in theory, each cycle doubles the amount of PCR product, two samples that differ in Ct by four cycles differ in PCR product by 16-fold. However this assumes 100% efficiency in the PCR reaction and does not take into account differences in the amount of starting material. A commonly used formula to estimate PCR product is the ΔΔCT method. The sample PCR product is normalized by subtracting the PCR product of a reference gene (such as actin). In addition, a control cell is also measured and its product is subtracted from the test sample after subtracting the signal for the same reference gene. Relative concentration = 2 -ΔΔCT , where the ΔΔCT = ΔCt sample minus ΔCt control. Harr, Robert R. Medical Laboratory Science Review (Page 506). F.A. Davis Company. Kindle Edition.

A direct smear from a nasopharyngeal swab stained with Loeffler methylene blue stain showed various letter shapes and deep blue, metachromatic granules. The most likely identification is: A. Corynebacterium spp. B. Nocardia spp. C. Listeria spp. D. Gardnerella spp.

A Corynebacterium spp. are part of the normal upper respiratory tract flora. Organisms display typical pleomorphic shapes often resembling letters such as Y or L, and metachromatic granules. Identification of C. diphtheriae, however, requires selective culture media and biochemical testing. Harr, Robert R. Medical Laboratory Science Review (Page 431). F.A. Davis Company. Kindle Edition.

Which of the following statements is true? A. Cystatin C is measured immunochemically B. The calibrator used for cystatin C is traceable to the National Bureau of Standards calibrator C. Cystatin C assays have a lower coefficient of variation than plasma creatinine D. Enzymatic and rare Jaffe reactions for creatinine give comparable results

A Cystatin C can be measured by enzyme immunoassay, immunonephelometry, and immunoturbidimetry. However, there is no standardized calibrator as for creatinine, and therefore, results vary considerably from lab to lab. The coefficient of variation for these methods tends to be slightly higher than for creatinine. Since the enzymatic methods are specific, they give lower plasma creatinine results than the Jaffe method in persons with normal renal function. However, they tend to give higher clearance results than for inulin or iohexol clearance because some creatinine is secreted by the renal tubules. Harr, Robert R. Medical Laboratory Science Review (Page 240). F.A. Davis Company. Kindle Edition.

If the steady-state drug level is too high, the best course of action is to: A. Decrease the dose B. Decrease the dose interval C. Decrease the dose and decrease the dose interval D. Change the route of administration

A Decreasing both dose and dosing interval will have offsetting effects on peak and trough blood levels. The appropriate dose can be calculated if the clearance or V d and f are known. For example, the initial dose is calculated by multiplying the desired peak blood drug concentration by the V d . Harr, Robert R. Medical Laboratory Science Review (Page 297). F.A. Davis Company. Kindle Edition.

If anti-K reacts 3+ with a donor cell with a genotype KK and 2+ with a Kk cell, the antibody is demonstrating: A. Dosage B. Linkage disequilibrium C. Homozygosity D. Heterzoygosity

A Dosage is defined as an antibody reacting stronger with homozygous cells (such as KK) than with heterozygous cells (such as Kk). In addition to Kell, dosage effect is seen commonly with antigens M, N, S, s, Fy a , Fy b, Jk a , Jk b, and the antigens of the Rh system. Harr, Robert R. Medical Laboratory Science Review (Page 123). F.A. Davis Company. Kindle Edition.

A hyaline mold recovered from a patient with AIDS produced rose-colored colonies with lavender centers on Sabouraud dextrose agar. Microscopic examination showed multiseptate macroconidia appearing as sickles or canoes. What is the most likely identification? A. Fusarium spp. B. Wangiella spp. C. Exophiala spp. D. Phialophora spp.

A Fusarium spp. are usually a contaminant but are sometimes seen as a cause of mycotic eye, nail, or skin infection in debilitated patients. Fusarium spp. is a hyaline (light) mold and grows on Sabouraud agar plates at 30°C within 4 days. The other three organisms are members of the Dematiaceae family (dark molds). Harr, Robert R. Medical Laboratory Science Review (Page 452). F.A. Davis Company. Kindle Edition.

A patient with hemolytic-uremic syndrome associated with septicemia has a haptoglobin level that is normal, although the plasma free hemoglobin is elevated and hemoglobinuria is present. Which test would be more appropriate than haptoglobin to measure this patient's hemolytic episode? A. Hemopexin B. Alpha-1 antitrypsin C. C-reactive protein D. Transferrin

A Hemopexin is a small β globulin that binds to free heme. Haptoglobin is an α-2 globulin that binds to free hemoglobin and disappears from the serum when intravascular hemolysis produces more than 3 grams of free plasma hemoglobin. However, haptoglobin is an acute phase protein, and hepatic production and release are increased in response to acute infections. The normal serum haptoglobin is most likely the result of increased synthesis and would not accurately estimate the hemolytic episode in this patient. Harr, Robert R. Medical Laboratory Science Review (Page 251). F.A. Davis Company. Kindle Edition.

An EIA screening test for HTLV I/II was performed on a whole-blood donor. The results of the EIA were repeatedly reactive but the confirmatory test was negative. On the next donation, the screening test was negative by two different EIA tests. The donor should be: A. Accepted B. Deferred C. Told that only plasma can be made from this donation D. Told to come back in 6 months

A If screening results are repeatedly reactive and the confirmatory test is negative for anti-HTLV and upon the next donation the EIA is negative by two different methods, the donor may be accepted. Harr, Robert R. Medical Laboratory Science Review (Page 163). F.A. Davis Company. Kindle Edition.

Cord cells are washed six times with saline and the DAT and negative control are still positive. What should be done next? A. Obtain a hellstick sample B. Record the DAT as positive C. Obtain another cord sample D. Perform an elution on the cord cells

A If the cord cells contain excessive Wharton's jelly, then further washing or obtaining another cord sample will not solve the problem. A heelstick sample will not contain Wharton's jelly and should give a valid DAT result. Harr, Robert R. Medical Laboratory Science Review (Page 158). F.A. Davis Company. Kindle Edition.

John comes in to donate a unit of whole blood at the collection center of the community blood supplier. The EIA screen is reactive for anti-HIV-1/2. The test is repeated in duplicate and is nonreactive. John is: A. Cleared for donation B. Deferred for 6 months C. Status is dependent on confirmatory test D. Deferred for 12 months

A If the initial EIA screen for anti-HIV is reactive, and the test is repeated in duplicate and found to be nonreactive, the blood components may be used. Harr, Robert R. Medical Laboratory Science Review (Page 162). F.A. Davis Company. Kindle Edition.

A 55-year-old male with early stage prostate cancer diagnosed by biopsy had his prostate gland removed (simple prostatectomy). His PSA prior to surgery was 10.0 ng/mL. If the surgery was successful in completely removing the tumor cells, what would the PSA result be 1 month after surgery? A. Undetectable B. 1-3 ng/mL C. Less than 4 ng/mL D. Less than 10 ng/mL

A If the tumor were confined to the prostate, the PSA would be undetectable 1 month following successful surgery, since there is no other tissue source of PSA. The half-life of PSA is 2.2-3.2 days, and the minimum detection limit of most assays is 0.2 ng/mL or lower. Therefore, it would require at least 2 weeks before the PSA level would be undetectable. The low minimum detection limit of the PSA assay, combined with the high tissue specificity of PSA, makes the test very sensitive in detecting recurrence. Harr, Robert R. Medical Laboratory Science Review (Page 309). F.A. Davis Company. Kindle Edition.

Key characteristics of infection with Plasmodium knowlesi include: A. Rapid erythrocytic cycle (24 hr), will infect all ages of RBCs, and can cause serious disease B. Erythrocytic cycle limited to young RBCs and causes a relatively benign disease C. The possibility of a true relapse from the liver, infection in older RBCs, and causes serious disease D. Extended life cycle (72 hr), will infect all ages of RBCs, and disease is similar to that caused by P. ovale

A Key characteristics of an infection with Plasmodium knowlesi include a rapid life cycle (24 hr), the potential to infect all ages of RBCs, and the possibility of serious symptoms similar to those seen with P. falciparum infections. There is no relapse from the liver with this species. Harr, Robert R. Medical Laboratory Science Review (Page 475). F.A. Davis Company. Kindle Edition.

Culture of a skin (hand) wound from a manager of a tropical fish store grew on Löwenstein-Jensen agar slants at 30°C in 10 days but did not grow on the same media at 37°C in 20 days. Given the following results, what is the most likely identification? Photochromogen = + Niacin = Neg Urease = + Heat-stable catalase (68°C) = Neg Nitrate reduction = Neg Tween 80 hydrolysis = + A. Mycobacterium marinum B. Mycobacterium kansasii C. Mycobacterium avium-intracellulare complex D. Mycobacterium tuberculosis

A M. marinum is typically recovered from cutaneous wounds resulting from infection when the skin is traumatized and comes into contact with inadequately chlorinated fresh water or salt water, such as in swimming pools or fish aquariums. The other three species are slow growers at 37°C. M. tuberculosis and M. avium-intracellulare complex are nonphotochromogens. M. avium-intracellulare complex is urease negative, M. tuberculosis is positive for niacin and nitrate, and M. kansasii is positive for nitrate and catalase. Harr, Robert R. Medical Laboratory Science Review (Page 442). F.A. Davis Company. Kindle Edition.

Acid-fast staining of a smear prepared from digested sputum showed slender, slightly curved, beaded, red mycobacterial rods. Growth on Middlebrook 7H10 slants produced buff-colored microcolonies with a serpentine pattern after 14 days at 37°C. Niacin and nitrate reduction tests were positive. What is the most probable presumptive identification? A. Mycobacterium tuberculosis B. Mycobacterium ulcerans C. Mycobacterium kansasii D. Mycobacterium avium-intracellulare complex

A M. tuberculosis is positive for niacin accumulation, while the other three species are niacin negative. M. ulcerans is associated with skin infections (in the tropics), does not grow at 37°C (optimal temperature is 33°C), and is not recovered from sputum. A serpentine pattern of growth indicates production of cording factor, a virulence factor for M. tuberculosis. Harr, Robert R. Medical Laboratory Science Review (Page 439). F.A. Davis Company. Kindle Edition.

Mycobacteria isolated from the hot water system of a hospital grew at 42°C. Colonies on Löwenstein-Jensen medium were not pigmented after exposure to light and were negative for niacin accumulation and nitrate reduction. The most likely identification is: A. Mycobacterium xenopi B. Mycobacterium marinum C. Mycobacterium ulcerans D. Mycobacterium haemophilum

A M. xenopi causes a pulmonary infection resembling M. tuberculosis and is frequently isolated from patients with an underlying disease such as alcoholism, AIDS, diabetes, or malignancy. It is often recovered from hot water taps and contaminated water systems and is a possible source of nosocomial infection. The other three species cause skin infections and grow on artificial media at a much lower temperature than M. xenopi (below 32°C). Harr, Robert R. Medical Laboratory Science Review (Page 440). F.A. Davis Company. Kindle Edition.

A lung biopsy obtained from an immunocompromised patient showed many "cup-shaped" cysts (gray to black) in a foamy exudate (green background) using Gomori methenamine silver (GMS) stain. The organism cannot be cultured because it does not grow on routine culture media for molds. The patient was diagnosed with pneumonia that resisted antibiotic treatment. The most likely identification is? A. Pneumocystis jirovecci (carinii) B. Histoplasma capsulatum C. Sporothrix schenckii D. Scopulariopsis spp.

A Pneumocystis jirovecii (carinii), most recently classified as a fungus but formerly as a parasite, is best recovered by bronchoalveolar lavage or induced sputum in immunocompromised patients. Open lung biopsy sample was the specimen of choice before the AIDS epidemic. Gomori methenamine silver stain is used to identify the organism; it stains the cyst form but not the trophozoites. Harr, Robert R. Medical Laboratory Science Review (Page 453). F.A. Davis Company. Kindle Edition.

Which of the following conditions is cause for rejecting an analytical run? A. Two consecutive controls greater than 2 s above or below the mean B. Three consecutive controls greater than 1 s above the mean C. Four controls steadily increasing in value but less than +- s from the mean D. One control above +1 s and the other below -1 s from the mean

A Rejecting a run when three consecutive controls fall between 1 and 2 s or when a trend of four increasing or decreasing control results occurs would lead to frequent rejection of valid analytical runs. Appropriate control limits are four consecutive controls above or below 1 s (41s ) to detect a significant shift, and a cusum result exceeding the ±2.7 s limit to detect a significant shift or trend. When controls deviate in opposite directions, the difference should exceed 4s before the run is rejected. Harr, Robert R. Medical Laboratory Science Review (Page 226). F.A. Davis Company. Kindle Edition.

A culture from an intra-abdominal abscess produced orange-tan colonies on blood agar that gave the following results: Oxidase = + Nitrate reduction = + KIA = Alk/Alk (H2 S)+ Motility = + (single polar flagellum) DNase = + Ornithine decarboxylase = + Growth at 42°C = Neg The most likely identification is: A. Shewanella putrefaciens B. Acinetobacter spp. C. Pseudomonas aeruginosa D. Chryseobacterium spp.

A S. putrefaciens produces abundant H2 S on KIA or TSI. Shewanellae are the only nonfermenters that produce H2 S on these media. Harr, Robert R. Medical Laboratory Science Review (Page 404). F.A. Davis Company. Kindle Edition.

A false-positive CAMP test for the presumptive identification of group B streptococci may occur if the plate is incubated in a(n): A. Candle jar or CO2 incubator B. Ambient air incubator C. 35°C incubator D. 37°C incubator

A The CAMP (hemolytic phenomenon first described by Christie, Atkins, and Munch-Petersen in 1944) test refers to a hemolytic interaction that is seen on a blood agar plate between the β-hemolysins produced by most strains of S. aureus and an extracellular protein produced by both hemolytic and nonhemolytic isolates of group B streptococci. When performing a CAMP test, the plate must be placed in an ambient air incubator at 35°C-37°C. Group A streptococci may be CAMP positive if the plate is incubated in a candle jar, high CO2 atmosphere, or anaerobically. Harr, Robert R. Medical Laboratory Science Review (Page 421). F.A. Davis Company. Kindle Edition.

She appears to be having a hemolytic anemia. The numerous polychromatophilic cells, spherocytes, as well as the jaundice all point to a hemolytic anemia. The polychromatophilic cells are reticulocytes produced to compensate from increased cell destruction. The spherocytes are a definite sign of a hemolytic anemia, such as in Hereditary Spherocytosis. The jaundice is due to the breakdown of excess hemoglobin released from destroyed RBCs. Polychromatophilia would not be seen in bone marrow failure, where few RBCs would be produced. An iron metabolism anemia would result in microcytic, hypochromic cells with few reticulocytes. A vitamin B12 deficiency would be characterized by oval macrocytes. Question Difficulty: Level 7

A 12-year-old child presents with jaundice and scleral icterus. The image to the right captures a representative section of the peripheral blood smear. Based on these smears as well as the clinical picture, what is most likely happening with this patient? She appears to be having bone marrow failure. She appears to be having an iron metabolism anemia. She appears to be having a hemolytic anemia. She appears to be having a vitamin B12 deficiency.

Screening cells and major crossmatch are positive on IS only, and the autocontrol is negative. Identify the problem. A. Cold alloantibody B. Cold autoantibody C. Abnormal protein D. Antibody mixture

A A cold alloantibody would show a reaction with screening cells and donor units only at IS phase. The negative autocontrol rules out autoantibodies and abnormal protein. Harr, Robert R. Medical Laboratory Science Review (Page 142). F.A. Davis Company. Kindle Edition.

Which PCO2 value would be seen in maximally compensated metabolic acidosis? A. 15 mm Hg B. 30 mm Hg C. 40 mm Hg D. 60 mm Hg

A In metabolic acidosis, hyperventilation increases the ratio of bicarbonate to dissolved CO2 . The extent of compensation is limited by the rate of both gas diffusion and diaphragm contraction. The lower limit is between 10 and 15 mm Hg PCO2 , which is the maximum compensatory effect. Harr, Robert R. Medical Laboratory Science Review (Page 195). F.A. Davis Company. Kindle Edition.

Should an A-negative woman who has just had a miscarriage receive RhIg? A. Yes, but only if she does not have evidence of active Anti-D B. No, the type of the baby is unknown C. Yes, but only a minidose regardless of trimester D. No, RhIg is given for term pregnancies only

A When the fetus is Rh positive or the Rh status of the fetus is unknown, termination of a pregnancy from any cause presents a situation in which an Rh-negative patient should receive RhIg. A minidose is used if the pregnancy is terminated in the first trimester. Harr, Robert R. Medical Laboratory Science Review (Page 159). F.A. Davis Company. Kindle Edition.

A neonatal bilirubin assay performed at the nursery by bichromatic direct spectrophotometry is 4.0 mg/dL. Four hours later, a second sample assayed for total bilirubin by the Jendrassik-Grof method gives a result of 3.0 mg/dL. Both samples are reported to be hemolyzed. What is the most likely explanation of these results? A. Hgb interference in the second assay B. Delta-bilirubin contributing to the result of the first assay C. Falsely high results from the first assay caused by direct bilirubin D. Physiological variation owing to premature hepatic microsomal enzymes

A The Jendrassik-Grof method is based upon a diazo reaction that may be suppressed by Hgb. Because serum blanking and measurement at 600 nm correct for positive interference from Hgb, the results may be falsely low when significant hemolysis is present. Direct spectrophometric bilirubin methods employing bichromatic optics correct for the presence of Hgb. These are often called "neonatal bilirubin" tests. A commonly used approach is to measure absorbance at 454 nm and 540 nm. The absorbance contributed by Hgb at 540 nm is equal to the absorbance contributed by Hgb at 454 nm. Therefore, the absorbance difference will correct for free Hgb. Neonatal samples contain little or no direct δ-bilirubin. They also lack carotene pigments that could interfere with the direct spectrophotometric measurement of bilirubin. Harr, Robert R. Medical Laboratory Science Review (Page 221). F.A. Davis Company. Kindle Edition.

A patient is admitted to the hospital. Medical records indicate that the patient has a history of anti-Jk^a. When you performed the type and screen, the type was O positive and screen was negative. You should: A. Crossmatch using units negative for Jk^a antigen B. Crossmatch random units, since the antibody is not demonstrating C. Request a new sample D. Repeat the screen with enzyme-treated screening cells

A The Kidd antibodies are notorious for disappearing from serum, yielding a negative result for the antibody screen. If a patient has a history of a Kidd antibody, blood must be crossmatched using antigen-negative units. If the patient is transfused with the corresponding antigen, an anamnestic response may occur with a subsequent hemolytic transfusion reaction. Harr, Robert R. Medical Laboratory Science Review (Page 136). F.A. Davis Company. Kindle Edition.

Which test would best distinguish between SLE and MCTD? A. Multiplex or ELISA test for anti-SM and anti-RNP B. Immunofluorescence testing using Crithidia as substrate C. Slide agglutination testing D. Laboratory tests cannot distinguish between these disorders

A The Ouchterlony (double) immunodiffusion assay may be used to identify and differentiate anti-Sm from anti-RNP. Multiplex and ELISA assays, using purified or recombinant antigens, are also available for this testing. Anti-Sm with or without anti-RNP is found in approximately one third of SLE patients. Anti-RNP in the absence of anti-Sm is found in over 95% of MCTD patients. Harr, Robert R. Medical Laboratory Science Review (Page 100). F.A. Davis Company. Kindle Edition.

Which of the following effects results from exposure of a normal arterial blood sample to room air? A. PO2 increased, PCO2 decreased, pH increased B. PO2 decreased, PCO2 increased, pH decreased C. PO2 increased, PCO2 decreased, pH decreased D. PO2 decreased, PCO2 decreased, pH decreased

A The PO2 of air at sea level (21% O2 ) is about 150 mm Hg. The PCO2 of air is only about 0.3 mm Hg. Consequently, blood releases CO2 gas and gains O2 when exposed to air. Loss of CO2 shifts the equilibrium of the bicarbonate buffer system to the right, decreasing hydrogen ion concentration and blood becomes more alkaline. Harr, Robert R. Medical Laboratory Science Review (Page 191). F.A. Davis Company. Kindle Edition.

The δ-ALA test (for porphyrins) is a confirmatory procedure for which test used for identification of Haemophilus species? A. X factor requirement B. V factor requirement C. Urease production D. Indole production

A The X factor requirement for growth is the cause of many inaccuracies when identifying Haemophilus spp. requiring this factor. False-negative results have been attributed to the presence of small amounts of hemin in the basal media, or X factor carryover from colonies transferred from primary media containing blood. The δ-ALA test determines the ability of an organism to synthesize protoporphyrin intermediates in the biosynthetic pathway to hemin from the precursor compound δ-aminolevulinic acid. Haemophilus species that need exogenous X factor to grow are unable to synthesize protoporphyrin from δ-ALA and are negative for the δ-ALA test. These include H. influenzae, H. haemolyticus, H. aegyptius, and H. ducreyi. Harr, Robert R. Medical Laboratory Science Review (Page 413). F.A. Davis Company. Kindle Edition.

A suspected Bacillus anthracis culture obtained from a wound specimen produced colonies that had many outgrowths (Medusa-head appearance), but were not β-hemolytic on sheep blood agar. Which test should be performed next? A. Penicillin (10-unit) susceptibility test B. Lecithinase test C. Glucose test D. Motility test

A The best differentiating test to perform on a suspected B. anthracis culture is the 10-unit penicillin disk test. B. anthracis is susceptible but other Bacillus spp. are not. Organisms suspected to be B. anthracis should be sent to a reference laboratory for final confirmation. All tests should be performed in a biological safety hood, and personnel should wear protective clothing to reduce risk from possible production of aerosols. Harr, Robert R. Medical Laboratory Science Review (Page 428). F.A. Davis Company. Kindle Edition.

Neutrophil phagocytosis and particle ingestion are associated with an increase in oxygen utilization called respiratory burst. What are the two most important products of this biochemical reaction? A. Hydrogen peroxide and superoxide anion B. Lactoferrin and NADPH oxidase C. Cytochrome b and collagenase D. Alkaline phosphatase and ascorbic acid

A The biochemical products of the respiratory burst that are involved with neutrophil particle ingestion during phagocytosis are hydrogen peroxide and superoxide anion. The activated neutrophil discharges the enzyme NADPH oxidase into the phagolysosome, where it converts O2 to superoxide anion (O2 - ), which is then reduced to hydrogen peroxide (H2 O2 ). Harr, Robert R. Medical Laboratory Science Review (Page 20). F.A. Davis Company. Kindle Edition.

When humans have hydatid disease, the causative agent and host classification are: A. Echinococcus granulosus—accidental intermediate host B. Echinococcus granulosus—definitive host C. Taenia solium—accidental intermediate host D. Taenia solium—definitive host

A The cause of hydatid disease is E. granulosus, and the human is classified as the accidental intermediate host. Infection occurs when humans accidentally ingest the eggs of E. granulosus and the hydatid cysts develop in the liver, lung, and other organs of the human instead of sheep (normal cycle). Harr, Robert R. Medical Laboratory Science Review (Page 471). F.A. Davis Company. Kindle Edition.

Septicemia The intended response is septicemia. Cytoplasmic vacuoles in monocytes and granulocytes correlate with septicemia with a sensitivity >95%. A relative and/or absolute lymphocytosis is the usual finding in viral infections. Monocytosis is often associated with tuberculosis, but toxic vacuolization is not a consistent finding. Eosinophilia is often associated with allergies and certain parasitic infections. Question Difficulty: Level 4

A peripheral blood smear with many myeloid cells was presented for morphology review (see image on the right). Toxic granulation and vacuoles in the neutrophil most likely represent which of the following conditions? Septicemia Viral infection Tuberculosis Active allergies

An incompatible donor unit is found to have a positive DAT. What should be done with the donor unit? A. Discard the unit B. Antigen type the unit for high-frequency antigens C. Wash the donor cells and use the washed cells for testing D. Perform a panel on the incompatible unit

A The incompatible unit may have red cells coated with antibody and/or complement. If red cells are sensitized, then some problem exists with the donor. Discard the unit. Harr, Robert R. Medical Laboratory Science Review (Page 142). F.A. Davis Company. Kindle Edition.

A stool culture from a 30-year-old man suffering from bloody mucoid diarrhea gave the following results on differential enteric media: MacConkey agar = clear colonies; XLD agar = clear colonies; Hektoen agar = green colonies; Salmonella-Shigella agar = small, clear colonies Which tests are most appropriate for identification of this enteric pathogen? A. TSI, motility, indole, urease, Shigella typing with polyvalent sera B. TSI, motility, indole, lysine, Salmonella typing with polyvalent sera C. TSI, indole, MR, VP, citrate D. TSI, indole, MR, and urease

A The most likely organism is a species of Shigella. Typically, Salmonella spp. produce H2 S-positive colonies that display black centers on the differential media (except on MacConkey agar). The biochemical tests listed are necessary to differentiate Shigella from E. coli because some E. coli strains cross-react with Shigella typing sera. Shigella spp. are one of the most common causes of bacterial diarrhea; group D (S. sonnei) and group B (S. flexneri) are the species most often isolated. Harr, Robert R. Medical Laboratory Science Review (Page 397). F.A. Davis Company. Kindle Edition.

Older developing stages (trophs, schizonts) of the fifth human malaria, Plasmodium knowlesi, resemble those of: A. Plasmodium malariae B. Plasmodium ovale C. Plasmodium falciparum D. Plasmodium vivax

A The older developmental stages of Plasmodium knowlesi (trophs, schizonts) resemble those seen in infections with P. malariae (band forms, rosette schizonts). Harr, Robert R. Medical Laboratory Science Review (Page 474). F.A. Davis Company. Kindle Edition.

SITUATION: Abdominal pain, fever, vomiting, and nausea prompted an elderly male to seek medical attention. A watery stool specimen producing no fecal leukocytes or erythrocytes was cultured and grew a predominance of gram-negative fermentative bacilli. The colonies were beta-hemolytic on blood agar and cream colored on MacConkey agar. The colonies were both oxidase and catalase positive. What is the most likely identification? A. Aeromonas hydrophilia B. Escherichia coli C. Salmonella spp. D. Shigella spp.

A The oxidase positive test result rules out the members of the Enterobacteriaceae family. Colonies of Aeromonas hydrophilia and Plesiomonas spp. might be mistaken for Vibrio spp. since all three grow as clear colonies on MacConkey agar, are beta hemolytic on blood agar, and are oxidase positive. Harr, Robert R. Medical Laboratory Science Review (Page 388). F.A. Davis Company. Kindle Edition.

Four units of packed RBCs were brought to the nurses' station at 10:20 a.m. Two units were transfused immediately, and 1 unit was transfused at 10:40 a.m. The remaining unit was returned to the blood bank at 11:00 a.m. The units were not refrigerated after leaving the blood bank. What problem(s) is (are) present in this situation? A. The only problem is with the returned unit; the 30-minute limit has expired and the unit cannot be used B. The unit should not have been transfused at 10:40 a.m. because the time limit has expired; this unit and the remaining unit should have been returned to the blood bank C. The returned unit may be held for this patient for 48 hours but cannot be used for another patient D. No problems; all actions were performed within the allowable time limits

A There is a 30-minute time limit for a unit of RBCs that is not kept under proper storage conditions (1°C-6°C). Harr, Robert R. Medical Laboratory Science Review (Page 149). F.A. Davis Company. Kindle Edition.

A bone marrow sample obtained from an immunocompromised patient revealed small intracellular cells using a Wright's stain preparation. Growth on Sabouraud-dextrose agar plates of a mold phase at 25°C and a yeast phase at 37°C designates the organism as dimorphic. The mold phase produced thick, spherical tuberculated macroconidia. What is the most likely identification? A. Histoplasma capsulatum B. Sepedonium spp. C. Sporothrix schenckii D. Coccidioides immitis

A Thermally dimorphic Histoplasma capsulatum produce microconidia and hyphal fragments at 37°C (yeast phase), whereas at 25°C (mold phase) the organism displays large, thick-walled, round macroconidia with knobby or knoblike projections. The yeast form is able to survive within circulating monocytes or tissue macrophages that can be demonstrated with Giemsa's or Wright's stain. Harr, Robert R. Medical Laboratory Science Review (Page 453). F.A. Davis Company. Kindle Edition.

What should be done if all forward and reverse ABO results as well as the autocontrol are positive? A. Wash the cells with warm saline, autoabsorb the serum at 4 degrees Celsius B. Retype the sample using a different lot number of reagents C. Use polyclonal typing reagents D. Report the sample as group AB

A These results point to a cold autoantibody. Washing the cells with warm saline may elute the autoantibody, allowing a valid forward type to be performed. The serum should be adsorbed using washed cells until the autocontrol is negative. Then the adsorbed serum should be used for reverse typing. Harr, Robert R. Medical Laboratory Science Review (Page 127). F.A. Davis Company. Kindle Edition.

Haemophilus influenzae The correct answer is Haemophilus influenzae. Each of the bacterial species listed could be involved in septic arthritis and culture is necessary to make the final identification. However, the Gram stain presented in the image is least suggestive of Haemophilus influenzae, which are more pleomorphic, with a mixture of short coccal forms and thin, filamentous forms. The few clusters of bacterial cells seen in the image are distinctly coccal, with flattening of the opposing ends. This feature is characteristic of Neisseria species. Kingella kingae, although a gram-negative bacillus, is a short bacillus and often presents Gram stain features indistinguishable from Neisseria species. Question Difficulty: Level 8

A 21-year-old female developed painful swelling of the left knee along with a low grade fever. The knee was painful to palpation, an effusion was evident, and the overlying skin was slightly erythematous. Fluid was aspirated and a gram stain was performed (as seen in the images to the right). Based on the Gram stain morphology, which of the following bacterial species is LEAST likely to serve as the etiologic agent in the case described? Neisseria meningitidis Haemophilus influenzae Kingella kingae Neisseria gonorrhoeae

A patient with a vitamin B12 anemia is given a high dosage of folate. Which of the following is expected as a result of this treatment? A. An improvement in neurological problems B. An improvement in hematological abnormalities C. No expected improvement D. Toxicity of the liver and kidneys

B Administration of folic acid to a patient with vitamin B12 deficiency will improve the hematological abnormalities; however, the neurological problems will continue. This helps to confirm the correct diagnosis of vitamin B12 deficiency. Harr, Robert R. Medical Laboratory Science Review (Page 16). F.A. Davis Company. Kindle Edition.

Although the pathogenicity of Blastocystis hominis remains controversial, newer information suggests that: A. Most organisms are misdiagnosed as artifacts B. Numerous strains/species are included in the name, some of which are pathogenic and some are nonpathogenic C. The immune status of the host is solely responsible for symptomatic infections D. The number of organisms present determines pathogenicity

B The name Blastocystis hominis contains approximately 10 different strains/species that are morphologically identical; some are pathogenic and some are nonpathogenic. Because we cannot separate these organisms by morphology, this probably explains why some patients are symptomatic and some remain asymptomatic with this infection. Harr, Robert R. Medical Laboratory Science Review (Page 475). F.A. Davis Company. Kindle Edition.

As one of the morphological families of parasites, features that characterize various Nematode species include: Disease may be transmitted via a direct fecal to oral route Filariform larvae may serve as an infective form for humans Both A and B None of the above

Both A and B The correct answer is C - both A and B are correct. Nematode infection (as in Ascaris lumbricoides) may occur as the result of ingestion of embryonated ova from contaminated soil. Or, as with Strongyloides stercoralis, infection is acquired by skin penetration with filariform larvae. Question Difficulty: Level 9

A patient's BUN is 60 mg/dL and serum creatinine is 3.0 mg/dL. These results suggest: A. Laboratory error measuring BUN B. Renal failure C. Prerenal failure D. Patient was not fasting

C BUN is affected by renal blood flow as well as by glomerular and tubular function. When blood flow to the kidneys is diminished by circulatory insufficiency (prerenal failure), glomerular filtration decreases and tubular reabsorption increases due to slower filtrate flow. Because urea is reabsorbed, BUN levels rise higher than creatinine. This causes the BUN:creatinine ratio to be greater than 10:1 in prerenal failure. Harr, Robert R. Medical Laboratory Science Review (Page 242). F.A. Davis Company. Kindle Edition.

SITUATION: An EDTA sample for TnI assay gives a result of 0.04 ng/mL (reference range 0-0.03 ng/mL). The test is repeated 3 hours later on a new specimen and the result is 0.06 ng/mL. A third sample collected 6 hours later gives a result of 0.07 ng/mL. The EKG showed no evidence of ST segment elevation (STEMI). What is the most likely explanation? A. A false-positive result occurred due to matrix interference B. Heparin should have been used instead of EDTA, which causes false positives C. The patient has suffered cardiac injury D. The patient has had an ischemic episode without cardiac injury

C EDTA is the additive of choice for troponin assays because it avoids microclots that can lead to false positive results when serum or heparinized plasma is used. Spurious false positives caused by matrix effects usually revert to normal when the test is repeated on a new sample. An AMI will cause the TnI to increase in subsequent tests. Results between 0.04-0.10 ng/mL are the result of cardiac injury, and indicate either AMI or an increased short-term risk of AMI. Harr, Robert R. Medical Laboratory Science Review (Page 270). F.A. Davis Company. Kindle Edition.

The following laboratory results were obtained from a 40-year-old woman: PT = 20 sec; APTT = 50 sec; thrombin time = 18 sec. What is the most probable diagnosis? A. Factor VII deficiency B. Factor VIII deficiency C. Factor X deficiency D. Hypofibrinogenemia

D Fibrinogen (factor I) is a clotting protein of the common pathway and is evaluated by the thrombin time. In hypofibrinogenemia (fibrinogen concentration <100 mg/dL), the PT, APTT, and TT are prolonged. In factor VII deficiency, the APTT is normal; in factor VIII deficiency, the PT is normal; and in factor X deficiency, the TT is normal. Harr, Robert R. Medical Laboratory Science Review (Page 54). F.A. Davis Company. Kindle Edition.

Potential problems using EDTA anticoagulant and holding the blood too long prior to preparation of thick and thin blood films include: A. Changes in parasite morphology, loss of organisms within several hours, and poor staining B. Loss of Schüffner's dots, poor adherence of the blood to the glass slide, and parasites beginning the vector cycle within the tube of blood C. Neither A nor B D. All of these options

D There are many changes that occur if blood is held longer than 1-2 hours prior to thick and thin blood film preparation. These include changes in parasite morphology, loss of parasites, poor staining, poor adherence of the blood to the slide, and the parasites beginning that portion of the life cycle that normally occurs within the vector. These changes are merely one reason that the ordering, specimen collection, processing, examination, and reporting for thick/thin blood films are considered STAT procedures. Harr, Robert R. Medical Laboratory Science Review (Page 475). F.A. Davis Company. Kindle Edition.

Starch crystals Starch crystals from body powders or from protective gloves often contaminate normal urine. They appear round to oval, are highly refractile, with an irregular indentation in the center. They may exhibit the "Maltese cross" appearance under polarized light. To differentiate starch from true pathologic elements, one needs to consider the other urinalysis results including the presence of blood, protein, or oval fat bodies. Question Difficulty: Level 2

Identify the urine sediment elements shown by the arrow: Yeast WBCs Fat Starch crystals

Acremonium sp.

Illustrated in the top image is 4 day growth of a smooth, glabrous colony with a light tan yellow surface, cultured from a patient who developed a subcutaneous abscess at the site where a bone marrow transplant was administered. The bottom image is a photograph of a methylene blue stained mount presenting long, delicate conidiophores at the tips of which are produced loose clusters of thin elongated conidia in an oriental letter or "diphtheroidal" pattern. With these observations, what is the most likely identification? Acremonium sp. Gliocladium sp. Fusarium sp. Trichoderma sp.

Cell Wall B Cytoplasmic membrane D Nuclear Material E Flagellum F Cytoplasmic membrane - D Cell Wall - B Nuclear Material - E Flagellum - F Question Difficulty: Level 3

Label the parts of this prototypical bacterium: Cell Wall Cytoplasmic membrane Nuclear Material Flagellum

Lewis Blood Group System is a human blood group unlike most others. The antigen is produced and secreted by exocrine glands, eventually adsorbing to the surface of red blood cells. Its expression is based on the genetic expression of the Lewis and Secretor genes. Based on the following genotype (Le) (Se), what would you predict the Lewis antigen phenotypic expression to be? Le(a- b-) Le(a+ b+) Le(a- b+) Le(a+ b-)

Le(a- b+)

Lysine iron agar is a less commonly used culture medium that is most helpful in the identification of: Shigella sonnei Citrobacter freundii Salmonella enteritidis Proteus mirabilis

Salmonella enteritidis Lysine iron agar produces a purple slant when inoculated by a bacterial species that decarboxylates lysine and a black deep by species that produce H2S. Both of these reactions are key to the identification of Salmonella species, including S. enteritidis. Although some of the other species listed in this exercise produce hydrogen sulfide, Salmonella enteritidis is the only one that decarboxylates lysine. Shigella sonnei are nonmotile; lysine decarboxylase negative; citrate negative; malonate negative; and H2S negative. Citrobacter freundii is indole negative; lysine decarboxylase negative; and is positive for melibiose. Proteus mirabilis is easily identified on culture media due to its swarming nature. It typically smells of "burnt chocolate". It is capable of deaminating phenylalanine. It is lysine decarboxylase negative. Question Difficulty: Level 7

Which of the following alpha thalassemia syndromes has the genotype -α/αα ? Silent carrier Alpha thalassemia minor Hemoglobin H disease Alpha thalassemia major

Silent carrier The genotype -α/αα is known as silent carrier. Only one of the four genes is missing. Individuals who are silent carriers show no clinical disease and demonstrate normal results during routine laboratory testing (Enough alpha chains can be made with only three functioning gene loci). This form of alpha thalassemia is usually discovered upon family studies. Alpha thalassemia minor occurs when two of the four alpha genes are missing. (--/αα, -α/-α) Hemoglobin H disease occurs when three of the four alpha genes are missing.(--/-α) Alpha thalassemia major occurs when all four of the alpha genes are missing. Question Difficulty: Level 7

Choroidal cells Image C shows a clump of choroidal cells. These are cells that line the choroid plexus and may be shed into the CSF. They are not diagnostically significant. Question Difficulty: Level 1

The arrows in the images below indicate cells that may be observed in CSF samples. Match each image to the cell's identification. Choroidal cells Monomacrophages Presumptive malignant cells Lymphocytes

Sepsis The intended response is sepsis. The pale gray-blue inclusions next to the cell membrane of the neutrophil are Döhle bodies. Döhle bodies may be seen in patients with sepsis, bacterial infections, and severe burns. Chédiak-Higashi Syndrome is characteristically associated with giant lysosomal granules in many varieties of WBCs. Patients with Chédiak-Higashi Syndrome are frequently characterized by partial albinism. Alder-Reilly anomaly is characterized by neutrophils with many large granules (called Alder-Reilly bodies) filled with mucopolysaccharides. These neutrophils with Alder-Reilly bodies resemble neutrophils with toxic granulation. Megaloblastic anemia is often characterized by another nonmalignant qualitative disorder of neutrophils called hypersegmentation where the nucleus has more than five lobes. Question Difficulty: Level 6

The cell containing the inclusions indicated by the arrows are often associated with which of the following conditions? Albinism Sepsis Alder-Reilly anomaly Megaloblastic Anemia

Lymphocytes This is the normal range of variation for lymphocytes in a cytospin. There are no monocytes, macrophages, or mesothelial cells present in this image. Lymphocytes typically have condensed chromatin and scant blue cytoplasm. Small numbers are normal, but Increased numbers can be associated with viral infections, meningitis, and others. Monocytes are large cells, often with convoluted nuclei and large cytoplasms, and are infrequently seen in CSF. Somethimes they can be seen in meningitis, or other conditions. Macrophages are not seen in normal CSF, but can be seen in meningitis and other conditions. They are large cells with abundant cytoplasm. Mesothelial cells are not found in normal CSF. If present, the distinction from macrophages is sometimes difficult. Question Difficulty: Level 3

The image on the right is a cytospin preparation of cerebrospinal fluid viewed at 1000X magnification. What is the identity of the primary blood cell type observed in this microscopic field? Monocytes Macrophages Mesothelial cells Lymphocytes

Bordetella bronchiseptica and Acinetobacter baumannii In this exercise, only the pair Bordetella bronchiseptica (motile) and Acintobacter baumannii (non-motile) produce the patterns seen in the left and right tubes respectively. As a rule of thumb, all Pseudomonas and Alcaligenes species are motile, the former via polar flagellae, the latter via peritrichous flagellae. Bordetella bronchispetica also has peritrichous flagellae and is motile. All Moraxella and Acinetobacter species are non-motile. Question Difficulty: Level 7

The pair of nonfermentative gram negative bacilli producing the motility reactions illustrated in the left (motile) and right (nonmotile) tubes respectively shown in the photograph are: Pseudomonas aeruginosa and Alcaligenes faecalis Moraxella osloensis and Pseudomonas cepacia Bordetella bronchiseptica and Acinetobacter baumannii Acinetobacter lwoffi and Moraxella lacunata

18 months-7 years The correct answer is 18 months-7 years. Mycobacterium scrofulaceum can be a commensal bacterium in the oropharynx. The correct age group in this is 18 months -7 years when a barrier break in the oral mucous membrane occurs during teething. The disease may also occur in late teenagers, during a time when the molar teeth are cut. The break in the gingival mucous membrane when the teeth penetrate permit access of the mycobacterial cells to the lymphatics, where they become trapped in the posterior cervical lymph nodes. Scrofula rarely occurs in other age groups and are limited to cases of injury to the oral mucosa or following dental surgery. Question Difficulty: Level 7

The photograph illustrates a classic case of scrofula infection, most commonly caused by Mycobacterium scrofulaceum. The age range when this condition is most likely to appear is: Less than one year 18 months-7 years 30-40 years Older than 65 years

Weak activity Weak activity is the correct answer because conversion of the slant only to a pink color in a Christensen's urea agar slant is produced by bacterial species that have weak urease activity. The reaction in the slant to the right is often produced by Klebsiella species, as an example. Strong activity is incorrect because strong urease activity is indicated by conversion of the slant and the butt of the tube to a pink color, as seen in the tube to the left. Proteus species are strong urease producers. Slant only inoculated is incorrect because the slant only reaction in the right tube may be seen early on if only the slant had been inoculated; however, with a strong urease producer, both the slant and the butt would turn. Therefore, the reaction is dependent on the strength of urease activity. Use of outdated medium is incorrect because if the media had been outdated for a prolonged period, either no reaction or the appearance of only a faint pink tinge would occur in the slant, the butt, or both. However, the reactivity would depend on the strength of urease production by the unknown organism. Question Difficulty: Level 4

The urease reaction seen in the Christensen's urea agar slant on the far right indicates: Weak activity Strong activity Slant only inoculated Use of outdated medium

A 52-year-old male received 2 units of packed red blood cells as an outpatient in the IV therapy unit. He had a 20-year history of head trauma and was quadriplegic. He had recurrent pneumonia and hematuria due to removal of a Foley catheter. His blood type was A positive with a previously identified anti-Fy^a. There was an ABO discrepancy in that the A1 cells were positive. The technologist attributed the reaction to the Fy^a antigen being present on the A1 cells. The patient also had a cold autoantibody. Two units of A-positive packed cells were crossmatched that were Fy^a negative, and were compatible. One unit was transfused at 11:30 a.m. without incident. The second unit was transfused at 2:16 p.m., and stopped at 3:55 p.m. due to reddish-brown-tinged urine discovered in his collection bag. A post transfusion specimen yielded a positive DAT, and plasma that grossly hemolyzed. A prewarm crossmatch was incompatible in both the pre- and postspecimen. Anti-E and c were present in the postspecimen. What reaction was most likely present? A. Acute hemolytic B. Febrile C. Allergic D. TRALI

A This case represents an acute hemolytic reaction where the patient had previous sensitization to E and c antigens. Given the history of anti-Fy a , an assumption was made that anti-Fy a was the cause of the positive reverse type with A1 cells, even though this antibody does not react at IS. This brings to light the importance of running a panel whenever the patient has a positive antibody screen regardless of previous results. Hemoglobinuria, positive DAT, and the hemolyzed postspecimen all are consistent with an acute hemolytic reaction. Harr, Robert R. Medical Laboratory Science Review (Page 147). F.A. Davis Company. Kindle Edition.

Disseminated intravascular coagulation (DIC) is associated with all of the following clinical conditions EXCEPT: Septicemia Obstetric emergencies Intravascular hemolysis Thrombocytosis

Thrombocytosis Disseminated intravascular coagulation (DIC) is a thrombo-hemorrhagic (clotting and bleeding) disorder involving the generation of intravascular clots with the consumption of coagulation factors/proteins and platelets. This condition is characterized by intravascular coagulation and hemorrhage with a decreased platelet count. DIC is most commonly observed in severe sepsis and septic shock. It is also associated with obstetric complications such as amniotic fluid embolism, abruptio placentae, hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome/eclampsia, as well as other conditions and disease states. Question Difficulty: Level 7

Burr cells Burr cells (echinocytes) may occur as an artifact or in cases of heart disease, uremia, bleeding ulcers, and stomach cancer. Burr cells have uniformly shaped pointed projections on the outer edge of the cell. Ovalocyes (megalocytes) have an oval or egg like shape. They are similar to elliptocytes, but have a fuller appearance. Ovalocytes are seen in Vitamin B12 and folate deficiencies. Sickle cells (drepanocytes) resemble a crescent and one end must be pointed. Sickle cells are associated with sickle cell anemia. Elliptocytes are rod, cigar, or sausage shaped. Elliptocytes are associated with hereditary elliptocytosis, hemoglobin C disease, pernicious anemia, sickle cell trait, and thalassemia. Question Difficulty: Level 1

What best describes the cells seen in this illustration? Ovalocytes Burr cells Sickle cells Elliptocytes

An 82-year-old male was admitted for renal failure. His type was B positive, and his antibody screen was negative. Two units of red cells were ordered. The first unit was transfused at 1:00 p.m. without incident. The second was started at 4:15 p.m. and stopped at 5:12 p.m., after the nurse observed the patient had expired. Vital sihns were taken at 4:30 p.m. with no abnormalities. A transfusion reaction was called and the blood unit, tubing, and paperwork sent to the blood bank. There were no clinical manifestations noted on the paperwork and no post-transfusion specimen was sent to the blood bank. What type of reaction most likely occurred? A Symptoms not related to transfusion B. Acute hemolytic reaction C. Anaphylactic reaction D. Volume overload

A This example represents a situation where the pathologist was not provided with all information needed to interpret the reaction. There were no patient symptoms, the patient had received another unit of red cells hours previously with no problems, and a postreaction specimen was not collected. Therefore, any serological abnormalities could not be identified. The FDA recommends collecting a specimen postmortem if a reaction is called, so that the transfusion reaction investigation can be completed. In this case, the pathologist interpreted the reaction as symptoms not related to transfusion because no symptoms were documented. Harr, Robert R. Medical Laboratory Science Review (Page 148). F.A. Davis Company. Kindle Edition.

How much anticoagulant would have to be removed from the collection bag given a donor who weighs 90 lb? A. 12 mL B. 15 mL C. 20 mL D. 23 mL

A To determine the amount of anticoagulant to remove when the donor is less than 110 lb, divide weight by 110 lb and multiply by 450 mL; divide that number by 100 and multiply by 14 (this gives the anticoagulant volume needed); then subtract this from 63 mL, which is the standard volume of anticoagulant in a 450 mL bag. The result is the amount of anticoagulant to remove. Harr, Robert R. Medical Laboratory Science Review (Page 155). F.A. Davis Company. Kindle Edition.

Cryptosporidium parvum Cryptosporidium parvum is the correct response. Characteristic of C. parvum are the tiny 4 - 6 µm in diameter acid-fast oocysts that typically adhere to intestinal lining cells, resulting in mal-absorption and other symptoms including cholera-like watery diarrhea. The oocysts are even staining and devoid of sporocysts. Cyclospora cayetanensis is an incorrect response. C. cayetanensis oocysts are spherical with an appearance similar to those of Cryptosporidium. The distinguishing characteristics are acid-fast oocysts that are twice the size of Cryptosporidium oocysts, ranging from 8 - 12 µm, and a slightly wrinkled cytoplasm with two sporozoites within each oocyst. Microsporidium species is an incorrect response. Microsporidium also produces tiny spores measuring no more than 2 µm in diameter. They are located within the cytoplasm of the epithelial cells instead of on the surface. These spores are non-acid fast, and best observed in trichrome or Weber stained preparations. Cystoisospora belli is an incorrect response. Isospora belli produces oocysts of that are large, measuring up to 30 µm, with a long oval shape. These oocysts have a thin, smooth outer wall and possess two intra-cytoplasmic sporocysts. Question Difficulty: Level 9

The story might be told that a pathologist, when first viewing an H & E - stained section of an endoscopic biopsy of duodenum (upper left image), may seek a consultation. The specimen was obtained from a patient with a mal-absorption syndrome. After observing tiny acid-fast globules along the intestinal epithelial lining cell (arrows, upper right image), one of the laboratory microbiologists was consulted for an answer. Having a presumptive identification in mind (lower left image), the microbiologist prepared an acid-fast stained smear of intestinal fluid (lower right image) and observed tiny 5 µm in diameter oocysts. From the multiple choices listed, select the presumptive identification, select what parasite the microbiologist might have reported. Cryptosporidium parvum Cyclospora cayetanensis Microsporidium species Cystoisospora belli

Mycobacterium chelonae Mycobacterium chelonae is the correct response. Characteristic is the rapid growth of gray-white smooth non-pigmented colonies both on chocolate agar and Middlebrook 7H10. The colony morphology and acid fast staining characteristics do not distinguish between M. chelonae and M. fortuitum. One approach to making the identification of M. chelonae is by demonstrating resistance to Ciprofloxacin and susceptibility to Polymyxin B, susceptibility patterns opposite to those of M. fortuitum. Negative reactions for nitrate reduction and iron uptake can also be used to make the separation. Mycobcterium fortuitum colony growth is also rapid and differences in acid fast staining appearance are not sufficient to separate M. fortuitum from M. chelonae. Differentiation M. fortuitum can be made by using a susceptibility test that demonstrates susceptibility to ciprofloxacin and resistance to Polymyxin B,, in contrast to the opposite patterns of susceptibility for M. chelonae. Positive reactions for nitrate reduction and iron uptake are also distinguish M. fortuitum. M. gordonae and M. scofulaceum colonies are slow growing usually beyond 10 days that along with the yellow pigmentation of colonies both before and after exposure to environmental light (scotochromogens) serve to presumptively separate these Mycobacteriacea species from M. chelonae. Susceptibility testing is not required to make this separation. Question Difficulty: Level 9

The tiny colonies growing on chocolate agar after 3 days incubation, as illustrated in the left plate in the upper composite photograph, were recovered from a skin abscess at the site of a contaminated needle injection. The colonies growing on Middlebrook 7H10 agar seen to the right in the composite image were larger, smooth, convex, and gray-white. Acid fast stains were positive for the appearance of slender bacilli, consistent with one of the rapidly growing Mycobacteria. A distinctive characteristic was the antibiotic resistance to Ciprofloxacin as illustrated in the left upper strip on the Petri dish susceptibility test shown in the lower photograph. Polymyxin B is susceptible illustrated by the vertical strip in the lower photograph. From these observations select from the multiple choices the identification of this isolate. Mycobacterium chelonae Mycobacterium fortuitum Mycobacterium gordonae Mycobacterium scrofulaceum

Lactobacillus species Lactobacillus species is the correct response. The colonies on sheep blood agar are gray white, convex, smooth and non-discriminatory. Observation of light alpha hemolysis would help to make a presumptive identification. Microscopic observation of gram stains reveal long, slender, Gram-positive bacilli arranged in long chains. The presumptive identification could be supported by demonstrating the lack of biochemical activity on an API strip or other assays. Bacillus cereus colonies growing on blood agar are large, flat, gray-yellow, with a granular consistency, and fimbriated edges. Distinctive also are zones of beta hemolysis surrounding the colonies. Microscopically, short gram-positive bacilli are arranged singly or in short chains, with central or sub-terminal spores. Oerskovia xantheneolytica colonies growing on blood agar are entire, convex, smooth, and yellow pigmented. Observation of gram stains reveal coccoid to short rod-shaped gram-positive bacilli lying singly or in loose clusters without the formation of chains. Distinctive is the production of lecithinase observed as areas of clearing around colonies growing on egg yolk agar. Actinomyces neuii colonies are small, white and slightly wrinkled. A. neuii is an aerotolerant Actinomyces species with good growth on blood agar incubated in 5% CO2. Microscopically slender, gram-positive bacilli are observed in a diphtheroidal arrangement. Positive catalase and strong CAMP reactions confirm a presumptive identification. Question Difficulty: Level 1

The tiny, gray-white, non-hemolytic colonies growing on blood agar are non-descript. The gram-stain reveals elongated, rectangular gram-positive bacilli in short chains. Key to the identification would be the lack of biochemical activity as seen on an inoculated API strip or other identification assays. This bacterium is usually recovered as a genital tract commensal, but has also been found to provide protection against other infective bacteria. With these observations, select from the multiple choices the identification of this isolate. Bacillus cereus Oerskovia xantheneolytica Lactobacillus species Actinomyces neuii

Iodamoeba butschlii Iodamoeba butschlii is the correct response. The trophozoites are relatively small, with "ball in socket" nuclei adjacent to the outer membrane. Observed also is a cyst with a single nucleus with an irregular karyosome surrounded by a vague clear space. An outer chromatin ring is not observed. Note the large cyst in the cytoplasm. Of interest, this cyst would appear yellow-brown when stained with iodine, from which the genus name is derived. Observing these trophozoites and cysts in a stool specimen is considered of little clinical significance in most cases. Chilomastix mesnili is an incorrect response. C. mesneli trophozoites are small with a single large nucleus placed immediately beneath the outer membrane and an adjacent cytosome. The cysts are lemon-shaped with a thin smooth cell wall, ranging from 6 - 10 um, with a distinct anterior knob. A single nucleus with a small karyosome is devoid of an outer chromatin ring. A cytostome in the form of a "shepherd's crook" is adjacent to the nucleus. Entamoeba hartmanni is an incorrect response. E. hartmanni trophozoites have an "entamoeba type" nucleus and a finely granular cytoplasm. The ova may present with from one up to four nuclei, each distinctive for having a central large karyosome surrounded by a blotchy chromatin ring. A small chromatin bar with rounded edges may also be seen. Endolimax nana is an incorrect response. E. nana trophozoites also have a single "ball in socket" nucleus. Differentiation is made by observing the cysts that are small, ranging from 6 - 8 um, and are characterized by the presence of four nuclei, each with a minute central karyosome surrounded by a clear space. The nuclei are devoid of a ring of outer chromatin, referred to as "ball in socket". Distinctive is the absence of a large cytoplasmic vacuole. Question Difficulty: Level 9

The trophozoites indicated by arrows and the 10 um oval cyst at the middle left in the photomicrograph were observed in a stool specimen from a person with mild intermittent diarrhea. From the multiple choice answers listed below, select the presumptive identification. Iodamoeba butschlii Chilomastix mesnili Entamoeba hartmanni Endolimax nana

Pseudomonas aeruginosa Pseudomonas aeruginosa is the correct answer. The O/F basal media are used to determine if the organism is a fermenter or oxidizer. The closed tube is overlaid with mineral to create an anaerobic environment, in which fermentation takes place. The open tube is not overlaid and the organisms is exposed to oxygen and will then exhibit oxidation, if applicable. A color change of yellow in either tube indicates a positive reaction of that biochemical process for the sugar added to the tube, which in this question is glucose. This image indicates that the closed tube that is overlaid with oil (left side of the image) is negative. The medium has not changed to yellow to indicate any process has occurred. Since fermentation occurs in the closed tube (anaerobic) we can determine this organism does not ferment glucose. The open tube (right side of image) does have a yellow color change at the top indicating a positive reaction for oxidation of glucose. Reviewing the list of organisms, Pseudomonas aeruginosa is the only organisms that does not ferment glucose but can oxidize glucose. Escherichia coli and Shigella sonnei are both part of the Enterobacteriaceae group of organisms. One of their key common characteristics is that they all ferment glucose. Thus, if the image were to show either of these organisms, the closed tube should be yellow, or positive for the fermentation of glucose. Aeromonas hydrophila, while not part of the Enterobacteriaceae, also ferments glucose. Thus, the closed tube in the image should again be yellow. Question Difficulty: Level 6

The tubes shown in the image are O/F basal medium with glucose and a pH indicator of bromthymol blue. As shown, the tube on the left has a large layer of mineral oil on top of the medium (closed), while the tube on the right does not have a mineral oil overlay (open). The image below demonstrates a typical reaction for which organism? Escherichia coli Shigella sonnei Aeromonas hydrophila Pseudomonas aeruginosa

Escherichia coli The correct response is Escherichia coli. Of the bacterial species listed, only Escherichia coli produces the acid/acid KIA reaction (lactose fermenter), is positive for indole production and does not utilize sodium citrate (negative reaction) as the sole source of carbon. Shigella flexneri, although some strains may be indole positive, is a non-lactose fermenter and would produce an alk/acid (red/yellow) reaction on KIA. Klebsiella oxytoca is a lactose fermenter and does produce indole; however, it is citrate positive. Enterobacter aerogenes is a lactose fermenter which is indole negative and citrate positive. Question Difficulty: Level 5

The tubes shown in this photograph reading from left to right are Kligler Iron Agar (KIA), tryptophane broth for detecting indole and Simmon's citrate. The KIA tube shows an entirely yellow slant and butt, the indole tube shows a layer of red color, and the Simmon's citrate tube is green in color. Of the bacterial species listed, the one most likely to produce the reactions observed is: Shigella flexneri Escherichia coli Klebsiella oxytoca Enterobacter aerogenes

Myelocyte - nucleated red blood cell The nucleated cell on the left is a somewhat abnormal myelocyte with a large nucleus and blue cytoplasm. This immature cell of the myelocytic series is not normally released into the peripheral blood of a healthy person. The cell on the right is a nucleated red blood cell at the stage of metarubricyte (also known as orthochromic normoblast), which is an immature erythroid stage, also not normally released. Nucleated red blood cells can sometime be mistaken as lymphocytes because of the condensed nucleus and bluish cytoplasm, but this cell's nucleus is relatively much smaller than a lymphcyte nucleus. Although this myelocyte could perhaps be mistaken as a monocyte because of the uneven nucleus, the cytoplasm of a monocyte is much more abundant and blue. These cells can be seen in many conditions that disrupt the bone marrow, including fibrosis or other bone marrow invasive disorders. Question Difficulty: Level 5

The two nucleated cells in this peripheral blood smear image can be identified as (left image-right image): Myelocyte - lymphocyte Monocyte- nucleated red blood cell Monocyte - lymphocyte Myelocyte - nucleated red blood cell

Cladosporium The production of dark, elliptical conidia in branching chains with the conidia separated by a delicate black scar or dysjunctor is characteristic of the cladosporium type sporulation. In rhinocladiella type sporulation, the conidia are borne from either side of a straight conidiophore in a picket fence arrangement. Acrotheca type sporulation is somewhat similar to the cladosporium type except that the chains are quite short and the conidia are derived circumferentially from the hyphae, much as the hooks on a hat rack. Phialophora type sporulation involves the production of vase-like phialides with a distinct mouth from which spherical or slightly elliptical conidia are produced in clusters. Question Difficulty: Level 5

The type of sporulation illustrated in this photomicrograph of a dematiaceous fungus is: Rhinocladiella Acrotheca Cladosporium Phialophora

Rhinocladiella Rhinocladiella is the correct answer because production of single conidia in succession both laterally and around the tip of a straight phialide is called the rhinocladiella type of sporulation, characteristic of Fonsecaea pedrosoi. Acrotheca type sporulation is incorrect because this type of sporulation is characterized by the production of short chains of elliptical conidia in a circular arrangement from the tips of branching phialides. Birds on a fence is incorrect because this type of arrangement of microconidia is characteristic of Trichophyton rubrum. This type of sporulation is somewhat reminiscent of the rhinocladiella type sporulation except that the conidia are more loosely held and alternate more from one side of the hyphae to the other. (Trichophyton rubrum is a hyaline rather than a dematiaceous fungus.) Acropetal in incorrect because this term refers to a type of sporulation where chains of conidia are formed with each new daughter cell produced from the previous one, leaving the oldest cell at the base of the chain. This type of sporulation is characteristic of Aspergillus species and Penicillium species. Question Difficulty: Level 5

The type of sporulation of the dematiaceous mold that is illustrated in this photomicrograph is called: Acrotheca Rhinocladiella Birds on a fence Acropetal

Pasteurella multocida Pasteurella multocida is a small Gram-negative, oxidase positive bacilli frequently associated with bite wounds from canines or felines. The organism grows on sheep blood agar as a smooth, gray, nonhemolytic colony with a musty, mushroom odor. It does not grow on MacConkey agar. Capnocytophaga canimorsus is a slow growing, Gram-negative fusiform or curved shaped bacilli. It is associated with dog bites or scratches but it is oxidase negative. It is a capnophilic organism that grow as medium, opaque, shiny, non-hemolytic organisms on blood agar but it does not grow on MacConkey. Moraxella catarrhalis is an oxidase-positive Gram-negative diplococcus that grows well on blood agar but not on MacConkey. The colony morphology is described as small translucent colonies. It is mostly associated with human infections primarily in the respiratory tract and not dog or cat bite wounds. Bordetella bronchiseptica is a small Gram-negative, oxidase positive bacilli that inhabits the respiratory tract of dogs and cats. Infections in humans include pneumonia, bacteremia, urinary tract infection and more, but not bite infections. The organism grows on sheep blood agar as a small convex colony but it also grows as a non-lactose fermenter on MacConkeys. Question Difficulty: Level 5

The upper image of a blood agar plate illustrates the smooth, gray, nonhemolytic colonies that were recovered after 36 hours incubation from a wound of the forearm of a 14-year-old boy following a dog bite. The colony had a musty or mushroom odor and is oxidase positive. It did not grow on MacConkey agar. The lower image illustrates the gram stain prepared from the colony. The most likely identification is: Capnocytophaga canimorsus Moraxella catarrhalis Pasteurella multocida Bordetella bronchiseptica

Enterobius vermicularis Enterobius vermicularis is the correct response. Illustrated in each of the photomicrographs are two key identifying features of this 10 mm long Enterobius vermicularis adult worm- the pointed tail ("pinworm") and the anterior alar wing-like expansion (blue arrow). Trichuris trichiura is an incorrect response. Trichuris adults are somewhat longer, measuring up 40 - 50 mm long. Male Trichuris worms have a thin caudal extremity with a 360 degree terminal coil, from which the colloquial name "whipworm" is derived. In intestinal infections, the head is buried in the epithelium and worms are rarely seen in stool specimens. Ascaris lumbricoides is an incorrect response. Ascaris worms are thick in diameter and very long (15 - 35 cm). Male worms have a smooth cuticle and a curved, non-pointed tail. Ancylostoma duodenale is an incorrect response. Ancylostoma (hookworm) adult worms measure up to 1.5 cm in length, and are distinguished by their mouth part that is fitted with a double pair of chitinous teeth. The tail section is rounded rather than pointed. In addition, rhabditiform larvae have a long, narrow buccal cavity and an inconspicuous genital primordium. Question Difficulty: Level 1

The upper photograph is of a 10 mm long nematode adult; the lower photograph is a close in view illustrating the transparent wing-like alar anterior expansion (blue arrow). These adult nematodes occupy the intestine and may occasionaly be seen at the anal opening of patients with diarrhea. Select from the answer choices below the presumptive identification of this nematode. Trichuris trichiura Ascaris lumbricoides Enterobius vermicularis Ancylostoma duodenale

Francisella tularensis The pustule seen in the upper photograph is specifically characteristic of Francisella tularensis. A pustule such as this develops at the site of the bite of an infected tick, caused by the proliferation of the injected organisms within the subcutaneous tissue. The inflamed area first develops into a painful, erythematous pustule, which in time ulcerates centrally and becomes covered by a dark gray or black eshcar. F. tularensis has a growth requirement for cysteine and cystine, which is provided by the yeast extract in the BCYE agar. The other bacterial species listed do not have this growth requirement and will grow well on routine blood agar. If the picture and media were not know, F. tularensis is the only Gram negative organism listed. It is a Gram negative coccobacilli. Bacillus anthracis is a spore-forming Gram positive bacillus. It produces a characteristic medusa head colony on blood agar. Erysipelothrix rhusiopathiae a non-spore forming Gram positive bacillus. Colonies grow well on blood agar and are typically pinpoint and non-hemolytic. Streptococcus pyogenes is Gram positive cocci in chains. This organism grows well on blood agar and shows beta hemolysis. Question Difficulty: Level 5

The well circumscribed cutaneous papule with the distinct outer erythematous border illustrated in the upper photograph developed over a period of 5 days at the site of a tick bite. The lower photograph illustrates colonies growing on a buffered charcoal yeast extract agar plate that had been inoculated with material from the ulcer bed three days before. Tiny, pale-staining Gram negative coccobacilli were seen on Gram stain. The most likely causative agent is: Bacillus anthracis Erysipelothrix rhusiopathiae Francisella tularensis Streptococcus pyogenes

Report it as no Salmonella or Shigella isolated The picture shown is an organism that is a lactose, xylose, and/or sucrose fermenter. Salmonella and Shigella would appear red on XLD and Salmonella would also have black centers from production of H2S. Yersinia enterocolitica and Escherichia coli O157:H7 would appear yellow on XLD but other media such as CIN for Yersinia and Sorbitol MacConkey for E. coli O157:H7 would be more selective for these isolates. XLD is only recommended for isolation of Salmonella and Shigella. Question Difficulty: Level 7

This Xylose Lysine Decarboxylase (XLD) medium shown in this photograph was isolated from a stool specimen of an immunocompetent adult. Your best action would be to: Report it as no Salmonella or Shigella isolated Work it up for possible Salmonella spp. Work it up for possible Yersinia enterocolitica Serotype it for Escherichia coli O157:H7

Centromere pattern This is an example of a centromere ANA pattern. This pattern is characterized by staining of discrete speckles in the nucleus of the interphase cells (a). This is staining of the centromere. There are usually 46 speckles, one for each set of chromosomes. Notice that discrete speckling is also seen in the chromosomal area of the metaphase mitotics (b).In order for the ANA to be positive there must be a clearly discernible pattern in the nucleus of the interphase cells. Metaphase mitotic cells are used to assist in identification of the ANA pattern. Peripheral or rim patterns will display distinct fluorescence around the nucleus membrane. Speckled patterns demonstrate scattered staining within the entire cell nucleus. Multiple nuclear dots are consistent with nucleolar staining. Question Difficulty: Level 6

This antinuclear antibody (ANA) test pattern is characterized by staining of discrete speckles in the nucleus of the interphase cells (a) and discrete speckling also in the chromosomal area of the metaphase mitotics (b) when viewed using fluorescent microscopy. This image represents which of the following patterns? Centromere pattern Peripheral or rim pattern Speckled Multiple nuclear dots

Chediak-Higashi syndrome The cell in the image along with the clinical picture are consistent with Chediak-Higashi syndrome. Chediak-Higashi cells appear to have giant lysosomes and fused granules in the cytoplasm. Alder-Reilly is characterized by the presence of prominent, dark-staining coarse granules that may occur in granulocytes, monocytes, and occasionally lymphocytes. May-Hegglin is characterized by larger, light blue-staining inclusions that resemble large Dohle bodies in granulocytes and monocytes. Pelger-Huet is characterized by hyposegmentation of the nucleus, where the nucleus may be bi-lobed or have no lobulation. Question Difficulty: Level 5

This autosomal recessive disorder is associated with recurrent bacterial infections and cells consistent with the cell in the image. Alder-Reilly anomaly May-Hegglin anomaly Chediak-Higashi syndrome Pelger-Huet anomaly

Bordetella bronchiseptica Bordetella bronchiseptica is the correct response. The colonies on blood agar are small, non-hemolytic and smooth with a "mercury droplet like appearance", translucent and non-pigmented. Smooth, light pink-staining colonies are seen on chocolate agar. As the primary cause of pertussis, colonies are most commonly recovered from expectorated or induced sputum samples. Observed in gram stains are small gram-negative coccobacilli, often bipolar stained, arranged singly or in pairs. The tube reactions illustrated in the image below reveal non-fermentation of glucose, positive nitrate reduction, and oxidative utilization of maltose. Distinctive for the identification of B. bronchiseptica is the rapid production of urea, with urease reactions often visible within 4 hours of incubation. The oxidase reaction is positive; Indole is not produced. Alcaligenes faecalis colonies on blood agar are grey pigmented and spreading, with light pigment extending into the adjacent agar. Small, plump, gram-negative cocco-bacilli are seen on gram stain. Acid is not produced from carbohydrates, including maltose. Cytochrome oxidase and catalase reactions are positive. The urease reaction is negative. Distinctive is the denitrification of nitrates with the production of gas. Acinetobacter baumannii colonies growing on blood agar are relatively large, white, entire, convex and opaque. Smooth, lightly pink pigmented non-distinctive colonies are produced on chocolate agar. Gram stain reveals small gram-negative coccobacilli in pairs or in short chains. The oxidase reaction is negative. Distinctive is the oxidative utilization of glucose and lactose on OF culture media, with maltose utilization being negative. Urease reactions vary with the strain, but are never strong. Comamonas acidovorans colonies are tiny, entire, slightly raised, smooth with a light yellow pigmentation. The oxidase test is positive and nitrites are reduced, but without the formation of gas. Colonies on chocolate agar are also tiny and without pigmentation. On gram stains, small slightly curved gram-negative bacilli occur singly or in pairs. C. acidovorans is classified as an asaccharolytic pseudomonad, with only weak reactions in OF fructose and mannitol; maltose utilization is negative. The urease reaction is negative. Question Difficulty: Level 9

This bacterial species shows good growth in 48 hours of entire, white, smooth, non-hemolytic colonies on blood agar (image to the left in the composite), and lightly pink pigmented, smooth entire colonies on chocolate agar (image to the right in the composite). This species is included in the class of motile, oxidase-positive non-fermenters, indigenous in the respiratory tract of domestic animals, but can cause human sinusitis and pneumonia in animal caretakers. Carbohydrate utilization is asaccharolytic except for oxidative utilization of maltose as illustrated in the lower composite image -- a key reaction is rapid urease production, and nitrates are reduced as also illustrated in the lower composite photograph. Based on these observations, select from the multiple choices the identification of this isolate. Bordetella bronchiseptica Alcaligenes faecalis Acinetobacter baumannii Comamonas acidovorans

Alpha thalassemia intermedia (Hemoglobin H Disease) The genotype pictured, --/-α, is known as Alpha thalassemia intermedia or Hemoglobin H disease. That is, three of the four alpha genes are deleted. These patients tend to form tetrads of beta globin chains, known as Hemoglobin H. Alpha thalassemia major or Hydrops fetalis occurs when all four alpha genes are deleted. These patients produce Hemoglobin Bart which is the formation of gamma globin tetrads. This condition is incompatible with life. Alpha thalassemia trait is the deletion of two of the four alpha genes. The silent carrier has one alpha gene deleted. They tend to have no clinical manifestation of a hemoglobinopathy. Question Difficulty: Level 5

This drawing depicts which alpha chain genotype? Alpha thalassemia major (Hydrops fetalis) Alpha thalassemia intermedia (Hemoglobin H Disease) Alpha thalassemia trait Silent carrier

Plasmodium falciparum This is a true parasitic infection. The species pictured here is Plasmodium falciparum. Plasmodium falciparum ring forms often contain two chromatin dots instead of one, as commonly seen in the other Plasmodium species, and are usually more delicate. Also shown in this image is the characteristic banana- or crescent-shaped gametocyte. Plasmodium vivax is typically characterized by seeing enlarged red blood cells with parasite forms in them as it usually invades the younger red blood cells (reticulocytes). The trophozoite is typically ameboid and may display large vacuoles and the gametocyte is rounded and fills the cell. Plasmodium malariae presents with a compact trophozoite that may have a band appearance as it extends across the entire cell. The schizont is also typically seen in a blood smear which has an average of eight merozoites which may be arranged in a "loose daisy petal" arrangement. Question Difficulty: Level 3

This image depicts a blood smear made from a patient with symptoms resembling malaria. Please identify the species listed below that matches the parasite forms shown in the image with arrows. Plasmodium vivax Plasmodium malariae Plasmodium falciparum Pseudoparasite

Hb H inclusions Hemoglobin H bodies precipitate with brilliant cresyl blue (a supravital stain) just inside the RBC membrane and are usually lightly colored and evenly distributed around the cell. Normal hemoglobin, or that which has not yet precipitated, remains evenly distributed in the RBC giving it a smooth appearance (arrow C). Brilliant cresyl blue that is used for this stain also precipitates remnants of RNA (similar to New methylene blue in the reticulocyte stain). These RNA remnants stain darker than Hemoglobin H bodies and are few in number as shown in the cell (arrow A). Howell-Jolly bodies, DNA, are dark purple inclusions visible with Wright stain. Pappenheimer bodies are blue iron deposits visible with Wright stain. Siderotic granules are iron deposits visible with iron stain (Prussian blue stain). Question Difficulty: Level 6

This image depicts a brilliant cresyl blue stained blood smear. What inclusion bodies are shown in the erythrocyte indicated by the arrow (B)? Howell-Jolly bodies Hb H inclusions Pappenheimer bodies Siderotic granules

Blastomyces dermatitidis Blastomyces dermatitides mold form produces short conidiophores with a single, round conidium. It gives the appearance of a "lollipop". This organism causes a significant systemic infection that typically begins in the respiratory tract. In the U.S., the reservoir for the organism is in the Mississippi, Missouri, and Ohio River Valleys. The mold form of Histoplasma capsulatum produce large, tuberculated, macroconidia. The infection is typically associated with the aerosolization of bird or bat excrement. The mold form of Sporothrix schenckii produces delicate, 'flowerette' arrangements of conidia at the end of a thin conidiophore. The subcutaneous infection is associated with working with living or dead vegetation. It is an occupational hazard for nursery workers, farmers, florists, and miners. The mold form of the Fusarium species produces a multi-cell, sickle-shaped macroconidia that are typically detached from the conidiophore on preparations. This organism is associated with mycotic keratitis after traumatic implantations in immunocompromised patients. Question Difficulty: Level 6

This image illustrates a lactophenol blue mount prepared from a mold recovered after 7 days incubation on brain heart infusion broth. The individual microconidia, each borne by a delicate conidiophore, suggests the mold form of the following organism: Blastomyces dermatitidis Histoplasma capsulatum Sporothrix schenckii Fusarium spp.

Basophilic stippling The red blood cell in image shown with the arrow is demonstrating coarse basophilic stippling. Basophilic stippling is precipitated RNA and appears as dark blue-purple, fine or course punctate granules distributed throughout the cytoplasm. Basophilic stippling is associated with various conditions but course stippling has an especially strong association with lead poisoning. Cabot rings are thin, pale blue rings or figure-eights that are composed of mitotic spindle remnant. Pappenheimer bodies are precipitated iron granules that appear as irregular clusters of small, light to dark blue granules, often near the periphery of the rbc. A Howell-Jolly body is a nuclear fragment (DNA) and appears as a dark blue-purple, dense, round granule in the cytoplasm. It usually occurs singly, but occasionally multiples may be seen. Question Difficulty: Level 1

This image is a Wright stained peripheral blood smear. The RBC that is indicated by the arrow contains which of the following? Basophilic stippling Cabot rings Pappenheimer bodies Howell-Jolly bodies

Codocytes The correct answer is codocytes. Codocytes are a typical erythrocyte morphology found in most thalassemias and hemoglobinopathies. Basophilic stippling is a typical erythrocyte morphology found in most thalassemias, but is not seen in this image. Ovalocytes are often found in conjunction with macrocytic cells. This is typically seen in megaloblastic anemia. Schistocytes are observed in this image, but are not a typical erythrocyte morphology found in thalassemias. Question Difficulty: Level 7

This image is from a patient with alpha thalassemia. Though not diagnostic for this condition, what morphology is present which would lead you to consider a quantitative disorder of hemoglobin synthesis? Basophilic stippling Codocytes Ovalocytes Schistocytes

Polychromatophilic RBCs The cells containing blue particulates in this image are classified as reticulocytes when using supravital stain. When using Wright stain, the cells would appear larger and a bit bluer, a key indication of reticulocytes; these cells would be described as polychromatophilic RBCs on Wright stained smears. Question Difficulty: Level 6

This image represents a field of red blood cells (RBCs) that were stained using a supravital stain. How would these cells appear if they were viewed on a Wright stained smear? Polychromatophilic RBCs RBCs containing basophilic stippling RBCs containing Cabot's rings RBCs containing Pappenheimer bodiesIllustrated in this photograph to the right is a sulfide indole motility (SIM) tube (left) and an esculin hydrolysis slant (right) after inoculation with an unknown gram positive bacillus and incubation at 30°C for 24 hours. Based on the reactions observed, the most likely identification is

Streptococcus pyogenes Streptococcus pyogenes is the correct answer. Streptococcus pyogenes is susceptible to bacitracin, shown by a zone of inhibition around the A disk. It is also resistant to SXT as shown by no zone of inhibition around the SXT disk. The left side of the agar is a CAMP test, which is negative, as no arrowhead of hemolysis is seen. Streptococcus agalactiae is CAMP test positive which would show a large arrowhead of hemolysis where the isolate meets the Staphylococcus aureus streak. Streptococcus agalactiae would also be resistant to bacitracin and SXT. Streptococcus dysgalactiae is susceptible to SXT and resistant to bacitracin. It is also CAMP test negative. Staphylococcus lugdunensis is a gram positive cocci and catalase positive. It is also not beta hemolytic. Question Difficulty: Level 5

This image shows a gram-positive, catalase negative coccus on sheep blood agar (beta-hemolytic). Please note the reactions with bacitracin (A) and trimethoprim sulfamethoxazole (SXT) disks seen on the right side of the agar plate. On the left side of the agar, a beta lysin-producing Staphylococcus aureus is streaked perpendicular to the unknown organism. What is the presumptive identification of this organism? Streptococcus agalactiae Streptococcus dysgalactiae Staphylococcus lugdunensis Streptococcus pyogenes

Salmonella spp. The correct answer is Salmonella spp. This isolate is a non-lactose and non-sucrose fermenter on TSIA, positive for H2S production, lysine decarboxylase positive, urea negative, citrate positive, phenylalanine deamination negative, indole negative, and ornithine positive. These biochemical results are all consistent with Salmonella spp. Shigella spp. would be H2S negative, lysine decarboxylase negative, urea negative, citrate negative, phenylalanine negative, and non-motile. Proteus vulgaris would be lysine and orntihine decarboxylase negative, citrate negative, phenylalanine positive, and produce indole. Citrobacter freundii generally ferments lactose or sucrose, would be phenylalanine negative, indole negative and lysine decarboxylase negative. Question Difficulty: Level 7

This member of the Enterobacteriaceae family is shown on triple sugar iron agar, lysine iron agar, urea agar, citrate agar, phenylanine deaminase agar, and motility indole ornithine agar in the photograph to the right. This organism should be identified as: Salmonella spp. Shigella spp. Proteus vulgaris Citrobacter freundii

Shigella sonnei Shigella sonnei is the correct answer because it is a sucrose and lactose non-fermenter, H2S negative, lysine negative, urea negative, citrate negative, phenylalanine negative, ornithine positive, indole negative, and non-motile. Salmonella is positive for H2S, lysine decarboxylase positive, and is motile. Escherichia coli would ferment lactose and sucrose, decarboxylase lysine, is motile, and is indole positive. Providencia spp. is citrate positive, phenylalanine deamination positive, indole positive, and is motile. Question Difficulty: Level 7

This member of the Enterobacteriaceae is shown on triple sugar iron agar, lysine iron agar, urea agar, citrate agar, phenylalanine deaminase agar, and motility indole ornithine agar. The most likely identification would be: Escherichia coli Salmonella spp. Shigella sonnei Providencia spp.

Plasmodium ring form This organism is a Plasmodium ring form. Note that this form consists of a "ring" of cytoplasm that is connected by a chromatin dot. Plasmodium species are the only parasites listed that actually invade unsuspecting red blood cells. Question Difficulty: Level 1

This parasite is found in blood. Plasmodium schizont Leishmania amastigote Plasmodium ring form Trypanosoma promastigote

Yersinia enterocolytica Yersinia enterocolytica is the correct answer. Cefsulodin-irgasan-novobiocin (CIN) agar is selective for Y. enterocolytica. It forms red centered colonies because the mannitol is fermented causing a change in pH of the neutral red indicator. Salmonella, Shigella, and Campylobacter will not grow on CIN medium. Salmonella and Shigella will appear as non-lactose fermenting colonies on MacConkey agar and highly selective media, such as Hektoen enteric (HE). HE medium also includes ferric salts which will show black centers in the colonies if hydrogen sulfide gas is produced. Salmonella will grow as blue-green colonies (a non-lactose fermenter) with black centers on HE and Shigella will produce blue-green colonies without black centers on HE. Stool specimens should also routinely include screening for Campylobacter spp. In order to screen for Campylobacter, Campy blood agar - a selective, enriched agar - is inoculated and incubated at 42 degrees Celsius in a microaerophilic atmosphere. Question Difficulty: Level 7

This photograph is of an isolate from a stool culture on a 4-year-old child with gastroenteritis. The medium contains cefsulodin, irgasan, novobiocin, bile salts, mannitol, neutral red, and crystal violet. Further identification tests will most likely identify this isolate as: Salmonella spp. Shigella spp. Campylobacter jejuni Yersinia enterocolytica

Eosinophil The cell in the image is an eosinophil. Eosinophils have a characteristic appearance with an abundance of large red-orange granules in the cytoplasm. These cells can be found in increased numbers in conditions such as parasitic infections and allergic reactions. Neutrophils are also granular, but have small, pink/purple cytoplasmic granules. The nucleus is usually segmented. Lymphocytes do not normally have cytoplasmic granules. The nucleus of a lymphocyte is usually round or oval. Basophils are also granular. They granules are bluish-black and are inconsistent in size. Question Difficulty: Level 2

This picture represents which type of leukocyte? Neutrophil Eosinophil Lymphocyte Basophil

Fusarium species Fusarium macroconidia are banana or canoe shaped and are formed singly, on small clusters or clustered together in mats termed sporodochia. The macroconidia are typically multicelled. Fusarium colonies can range in color from rose to mauve to orange. This colony has the distinctive rose-red to purple pigmentation which is characteristic. Beauveria is an insect pathogen. They have abundant, single celled tear shaped sympodulconidia are formed on sympodulae. (Blastic conidia formed on condigenous cell by growth of a succession of apices, each originating below and to one side of the last.) Chrysosporium wide-based, single-celled conidia are produced on nonspecialized cells. Geotrichum microscopically abundant arthroconida are seen. Question Difficulty: Level 1

This rapidly growing hyaline fungus is the most common cause of Keratomycosis (an infectious disease of the cornea). The colonies can range in color from rose to mauve to orange. This organism is commonly recovered from blood and grows on sabourauds dextrose agar with brain heart infusion. The microscopic appearance shows abundant banana or canoe shaped macroconidia. What fungus causes this disease? Beauveria species Fusarium species Chrysosporium species Geotrichum species

Chronic inflammation There is a broad based increase in the gamma band, corresponding to polyclonal hypergammaglobulinemia, as seen in chronic inflammation as well as an increase in the alpha-1 and alpha-2 regions. Question Difficulty: Level 6

This serum protein electrophoresis scan most likely represents which condition? Chronic inflammation Myocardial infarction Liver disease Monoclonal gammopathy

Entamoeba histolytica This picture shows the trophozoite stage of E. histolytica. Due to the central location of the karysome and the engulfed RBC seen, this can be identified as E. histolytica and not Entamoeba dispar, which is a commensal that shows all the same characteristics of E. histolytica, minus engulfed RBCs in the trophozoite stage. E. histolytica typically has a central kaysome with fine/even peripheral chromatin. Entamoeba hartmanni and Entamoeba histolytica are basically identical with the exception of size. Entamoeba hartmanni is typically smaller that Entamoeba histolytica, measuring less than 10 µm. Entamoeba coli has a trophozoite stage that contains an eccentric karyosome and uneven peripheral chromatin. Artifact is a microscopic structure or form that resembles a parasite, also called a confuser or pseudoparasite. Question Difficulty: Level 4

This suspicious form, found in a stool sample, measures 15 µm. What is it? Entamoeba histolytica Entamoeba hartmanni Entamoeba coli Artifact

Schistosoma haematobium The only egg, as seen in the photograph, typically recovered in urine samples is that of Schistosoma haematobium. This organism is characterized by its distinct shape, particularly the presence of a large terminal spine opposite a rounded end. The standard method of diagnosis is by the detection of characteristic eggs in feces for Schistosoma japonicum which has a small lateral spine. Since this is showing an actual egg form of a parasite, it would not be considered a pseudoparasite. Although Trichomonas vaginalis may be recovered from a urine sample, it is relatively small in size (average length = 13 µm) and assumes the characteristic flagellate trophozoite appearance. Question Difficulty: Level 4

This suspicious form, found in urine, measures 120 µm by 50 µm. What is the appropriate identification? Schistosoma japonicum Pseudoparasite Trichomonas vaginalis Schistosoma haematobium

Enterobius vermicularis egg The correct response is Enterobius vermicularis. Pinworm or Enterobius vermicularis eggs are routinely found on cellophane tape preparations. Their size, asymmetric shape, slightly flattened side and convex side, somewhat refractive appearance and the presence of a double layer cell wall aid in their identification. Trichuris trichura, or whipworm eggs, are characteristically elongated or lemon shaped, resembling a football or barrel with polar plugs. The eggs of Ascaris lumbricoides are oval and usually measure from 70-90 mm by 40-45mm; the albuminous outer coat is an important identifying characteristic. A pseudoparasite is "false parasite" which may be either a commensal or a temporary parasite which is ingested and survives briefly in the host intestine. A pseudoparasite may also be an object or an organism that is mistaken for a parasite. This image is not that of a pseudoparasite. Question Difficulty: Level 3

This suspicious form, seen in a cellophane tape preparation, measures 54 mm by 28mm. Trichuris trichiura egg Ascaris lumbricoides egg Enterobius vermicularis egg Pseudoparasite

Which of the following fungi is the cause of tinea pedis, ringworm of the feet? Trichophyton rubrum Microsporum canis Fusarium species Aspergillus species

Trichophyton rubrum Trichophyton rubrum is the correct response. T. rubrum is a dermatophyte that commonly causes an itching, scaling skin infection of the feet, known as tinea pedis as well as ringworm of the nails (tinea unguium), and body (tinea corporis). Microscopum canis is zoophilic and causes ringworm in cats, dogs, and other animals. Children may become infected through an infected pet. M. canis is associated with ringworm of the scalp (tinea capitis) and ringworm or the body (tinea corporis), but not ringworm of the feet. Fusarium species are opportunistic pathogens and may be associated with mycotic keratitis, mycetoma, pulmonary disease and skin and nail infections, but not ringworm. Aspergillus species are widespread in nature and are a common laboratory contaminant. Aspergillosis is an opportunistic infection and may involve the lungs, eyes, heart or central nervous system, but does not cause ringworm. Pulmonary aspergillosis includes allergic pulmonary aspergillosis, commonly known as "fungus ball" infections. Question Difficulty: Level 8

Anti-Fya and anti-C The correct answer is anti-Fya and anti-C. In this case, an enzyme panel was performed as well. Enzyme panels are usually performed in order to destroy (Duffy, MN, Xga, and variable S,s)or strengthen (Rh, Kidd, Lewis, P & Vel blood group system) antibodies. This is very helpful when more than one antibody is present as the reactions can mask the underlying antibody. The results clearly show the presence of an Anti-Fya antibody before the enzyme treated cells were utilized. With the enzyme panel results, it is clear that Anti-C was the underlying antibody. There may be other antibodies which cannot be formally ruled-out, but they do not match the pattern shown here. Question Difficulty: Level 7

Upon admission for thoracic surgery, a patient's physician ordered a type and screen. The patient is O positive. After a positive antibody screen was obtained, an antibody identification was performed. The results are shown on the right. Which antibodies are most likely present and causing the reactions shown? Note: You are ONLY identifying the antibodies most likely causing the reaction. You may have additional antibodies which have not yet been ruled out. Anti-D and anti-Fya Anti-Fya and anti-C Anti-S and anti-K Anti-C and anti-S

Previous subarachnoid hemorrhage Xanthochromia may be an indication of previous subarachnoid hemorrhage (SAH). The presence of dark, granular, iron-laden hemosiderin deposits, indicated by the blue arrows, and yellow, crystalline, iron-free hemotoidin crystals (red arrows) in macrophages, point to an SAH several hours to days prior to CSF analysis. Macrophages begin to appear in CSF approximately two hours after bleeding occurs into the central nervous system. The macrophages start to phagocytize red blood cells (RBCs). As the RBCs degenerate further, the breakdown products are seen in the phagocytic cells as hemosiderin deposits or hematoidin crystals. The appearance of hemosiderin and hematoidin crystals occurs approximately 18 hours following an SAH and may be present in the CSF for several months. If a CSF sample from a traumatic tap is centrifuged, the supernatant would be clear rather than xanthochromic, if the sample was analyzed within one hour of sample collection. Many RBCs would be present, but hemosiderin deposits and hemotoidin crystals would not be present. These findings are also not associated with leukemia and they are not normal findings in a microscopic CSF specimen. Question Difficulty: Level 3

Upon centrifugation, a cerebrospinal fluid (CSF) sample supernatant exhibited xanthochromia. The image is a Wright-Giemsa stained smear that was made from that CSF sample. What condition is probably related to these macroscopic and microscopic findings? Previous subarachnoid hemorrhage Traumatic tap Leukemia This is a normal microscopic finding for a CSF specimen

Minimum inhibitory concentration (MIC) susceptibility tests should be performed against other beta lactam antibiotics for Streptococcus pneumoniae isolates from blood cultures and other sterile body fluids. The reason for this is due to an emerging resistance against penicillin and other beta lactam antibiotics. However, there is one antibiotic that is used to treat drug resistant Streptococcus pneumonia infections and MIC results should be questioned when a resistant susceptibility is found. Which of the following antibiotics does Streptococcus pneumonia still remain sensitive? Cefotaxime Ceftriaxone Vancomycin Tetracycline

Vancomycin Vancomycin is correct as this is the last resort drug for multi-drug resistance Streptococcus pneumoniae infections. Cefotaxime and Ceftriaxone are incorrect as they are third generation cephalosporins that have demonstrated resistance against Streptococcus pneumoniae isolates. Tetracycline is incorrect as resistance is common in Streptococcus pneumoniae isolates. Question Difficulty: Level 8

Gram stains are performed on positive blood culture bottles. Each of the following responses correctly matches the organism with its description EXCEPT: Large, gram-positive rods with square ends occurring in short or long chains = Bacillus anthracis Small gam-negative coccobacillus or bacillus demonstrating bipolar staining = Yersinia pestis Very tiny, pale staining, gram-negative coccobacillus often arranging in pairs = Fusobacterium species Small, gram-negative coccobacilli that may stain very faintly or appear gram-positive due to retention of crystal violet stain; individual cells present = Brucella species

Very tiny, pale staining, gram-negative coccobacillus often arranging in pairs = Fusobacterium species Fusobacterum are long, thin, filamentous gram-negative bacilli with tapered ends that may arrange end to end. F. necrophorum may show pleomorphism with irregular or pale staining and swollen ends. Bacillus anthracis is a large, gram-positive rod with square or concave ends. It usually forms short chains in clinical specimens, but often forms long chains in culture material. There may be central to sub-terminal, oval spores with no significant swelling of the cell; spores are usually not observed, but their presence increases with the age of the culture. Y. pestis is a gram-negative bacillus or coccobacillus that can form short chains and resemble other Enterobacteriaceae. Gram stains performed from blood culture or other liquid media may show the characteristic bipolar staining, referred to as "safety-pin" morphology. Brucella species are small, gram-negative coccobacilli that stain very faintly and tend to retain crystal violet, especially in blood cultures. For this reason, they may initially be identified as gram-positive. To improve visualization, a two-minute counterstain with safranin should be used instead of the traditional method. Question Difficulty: Level 7

Centromere Centromere. This pattern is characterized by staining of discrete speckles in the nucleus of the interphase cells. This is staining of the centromere. There are usually 46 speckles one for each set of chromosomes. Notice the discrete speckling is also seen in the chromosomal area of the metaphase mitotics. Note: (a) points to the nuclei of several interphase cells, the primary consideration for discerning the ANA pattern and (b) indicates a metaphase mitotic cell. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in identification of the ANA pattern. The Homogeneous ANA pattern is characterized by smooth staining in the nucleus of the interphase cells. The nucleoli may or may not stain. Notice the smooth staining in the chromosomal area of the metaphase mitotic cells. The Speckled ANA pattern is characterized by granular/speckled staining in the nucleus of the interphase cells and an absence of staining in the chromosomal area of the metaphase mitotic cells. The Nucleolar ANA pattern is characterized by staining in the nucleoli of the interphase cells. Question Difficulty: Level 6

What antinuclear antibody (ANA) staining pattern is demonstrated in this microscopic, fluorescent test image? Homogeneous Speckled Nucleolar Centromere

Acanthocytes These are acanthocytes. Acanthocytes have 3-12 thorn-like projections (often with knobby ends) that are uneven in length and are irregularly spaced around the cell. Acanthocytes are easy to distinguish from the background of a peripheral smear because they appear to be saturated with hemoglobin and have little to no central pallor. Despite its appearance, the MCHC is in the normal range. Burr cells, also known as echinocytes, are red cells with spicules that are rounded and evenly spaced over the entire surface of the red cell. Burr cells are mostly normochromic, normocytic. Schistocytes are fragmented cells that are split, cut, or broken due to trauma to the membrane. The shape of schistocytes is variable. Sickle cells, also known as drepanocytes, are crescent or sickle shaped cells with pointed projections at one or both ends of the cell. These are present in patients with sickle cell disease. Sickle cells are rigid and are the result of hemoglobin polymerization. Question Difficulty: Level 4

What are the abnormal red blood cells that are indicated by the arrows in this image? Acanthocytes Burr cells Schistocytes Sickle cells

Spherocytes The cells indicated by the arrows in the image are spherocytes. Spherocytes are red blood cells which have decreased surface to volume ratio and therefore appear smaller with a deeper pink color. Spherocytes have lost their bi-concave shape and are spherical in shape, hence the name. Spherocytes can be caused by damage to the RBC membrane. Echinocytes are crenated red blood cells and have short projections around the periphery of the cell. The can be caused by osmotic imbalance or can be artifacts. Elliptocytes are elongated RBCs with a narrow oval shape. They are caused by a membrane defect. Stomatocytes have a slit-like area of pallor, and can be caused by increased sodium and decreased potassium concentrations within the RBC. Question Difficulty: Level 1

What are the cells that are indicated by the arrows in this peripheral blood smear image? Echinocytes Elliptocytes Spherocytes Stomatocytes

Stomatocytes The cells indicated by the arrows are stomatocytes. Stomatocytes, also known as mouth cells, have a rectangle shaped central pallor in contrast to normal red blood cells. Stomatocytes have been compared to "coffee beans" or "kissing lips" in appearance. They can be observed as artifact or in conditions such as hereditary stomatocytosis and alcoholic cirrhosis. Keratocytes, also known as helmet cells, appear with one or several notches with projections that look like horns. Drepanocytes, also known as sickle cells, appear as crescent or boat shaped. Schistocytes are RBC fragments. Question Difficulty: Level 1

What are the cells that are indicated by the arrows in this slide? Keratocytes Stomatocytes Drepanocytes Schistocytes

Russell bodies The prominent cell is a Mott cell on a peripheral blood smear from a patient with multiple myeloma. The globular inclusions are immunoglobulin accumulations (Russell bodies) representing the accumulation of excessive mucopolysaccharides and globulins within endoplasmic reticulum. Question Difficulty: Level 7

What are the globular inclusions in this cell? Bacteria Fat droplets Vacuoles Russell bodies

Bacteria These are rod-shaped bacteria, usually indicative of urinary tract infections. The presence of white blood cells supports this identification rather than "artifact," because white blood cells are usually present with bacteria. Calcium oxalate crystals can be seen in acid or neutral urine. They may also be present in normal urine. They characteristically occur as octahedral or envelope shapes. They can also be viewed as having a Maltese cross when one focuses up and down through the crystal. Triple phosphate crystals appear as colorless prisms with 3 to 6 sides and oblique ends, or as "feathery sleeves". The have been described as "coffin lid shaped", and can occur normally in alkaline urine. They may indicate the presence of an infection. Question Difficulty: Level 2

What are the microscopic elements that are indicated by arrows in this image? Bacteria Calcium oxalate crystals Triple phosphate crystals Artifact

Pappenheimer bodies These inclusions are Pappenheimer bodies and the erythrocytes containing them are called siderocytes. In Wright-stained smears the inclusions stain as purple dots. The granules stain positively with the Prussian blue iron stain, as shown in the lower photograph. Howell-Jolly bodies are larger, round, non-refractile inclusions that stain dark-blue to purple. Basophilic stippling are dark-blue fine, round granules. These granules are typically evenly distributed throughout the cell. Malarial ring forms are larger and distinctly ring-shaped, with one or two chromatin dots. Multiple ring forms may be seen in an erythrocyte. Question Difficulty: Level 5

What are the red cell inclusions in this split frame photomicrograph of peripheral smears (Wright's and Prussian Blue)? Howell-Jolly bodies Basophilic stippling Malarial ring forms Pappenheimer bodies

Auer rods The correct answer here is Auer rods. Auer rods are an abnormal fusion of primary granules. They are useful in differentiating acute myeloblastic leukemias from acute lymphoblastic leukemias. Auer rods are most commonly found in promyelocytes but can also be found myeloblasts. Dohle bodies are light blue inclusions located in the cytoplasm of neutrophils that are the reminents of the rough endoplasmic reticulum. Toxic granules are dark course granules found throughout the cytoplasm of neutrophils. Toxic granulation is commonly found in patients with sepsis. Bacteria is uncommonly found in the cytoplasm of white blood cells. Question Difficulty: Level 1

What are the white blood cell inclusions that are indicated by the arrows in this image? Dohle bodies Auer rods Toxic granules Bacteria

Lymphocytes In flow cytometry, gating is the process of isolating cells with the same light-scattering or fluorescence properties by electronically placing a gate around them. In this image, the cells gated represent the lymphocyte population. If you apply the concept that forward scatter is cell size and side scatter is granularity, the differential representation in this diagram is as follows: Lymphocytes are in red Monocytes are yellow Granulocytes/neutrophils are purple Question Difficulty: Level 5

What cell population is gated in this peripheral blood sample case analyzed by flow cytometry? Monocytes Lymphocytes Granulocytes Neutrophils

Transfusion dimorphism The intended response is "transfusion dimorphism". The microcytic, hypochromic erythrocytes suggests iron deficiency anemia. Interspersed among these cells are normocytic, normochromic erythrocytes suggesting two populations of red cells following transfusion. This was a case of severe iron deficiency treated with red cell transfusions and iron supplement. In hereditary spherocytosis, up to 25% of the RBC population may appear as microspherocytes. A possible finding on the peripheral blood smear in a case of lead poisoning is basophilic stippling. In some instances, lead poisoning may also present with a microcytic, hypochromic anemia, however, many children with high levels of lead do not have microcytic, hypochromic anemia. In folic acid deficiency, the RBC's are macrocytic. Question Difficulty: Level 5

What condition/situation is associated with the peripheral blood picture in the image on the right? Hereditary spherocytosis Lead poisoning Transfusion dimorphism Folic acid deficiency

Döhle body The arrow is pointing to a Döhle body. Döhle bodies are small, blue-staining inclusions seen in the cytoplasm of mature and immature neutrophils in the presence of bacterial infections, drug intoxication, burns, cytokine therapy, surgery, or pregnancy. They may be seen in cells that also contain toxic granules and/or vacuoles. Alder-Reilly inclusions are purple-red particles in the cytoplasm of neutrophils, eosinophils and basophils. The particles are precipitated mucopolysaccharides. Alder-Reilly inclusions are frequently seen in patients with genetic mucopolysaccharidosis, such as Hurler's, Hunter's and Maroteaux-Lamy. Auer rods are fused lysosomes (primary granules) that appear as red, needle-like crystalline inclusions in the cytoplasm of myeloblasts. Auer rods can be seen in Acute Myeloid Leukemia (FAB M1 classification). Toxic granulation has very dark prominent granulation. The granulation can be seen in neutrophils or monocytes. Toxic granulation is most often associated with infectious states. Question Difficulty: Level 4

What cytoplasmic inclusion is indicated by the arrow in this image? Alder-Reilly inclusion Döhle body Auer rod Toxic granulation

Ringed sideroblast The image in this question shows a ringed sideroblast. Ringed sideroblasts are red blood cell precursors, which have an abnormally increased amount of iron surrounding their nucleus. Iron stain, such as Prussian blue, is used to stain the iron in these cells. Ringed sideroblasts are associated with sideroblastic anemia, myelodysplastic syndromes, and other leukemic and genetic conditions. A siderocyte is a red blood cell precursor that contains iron in the cytoplasm. These cells would stain positive for iron with the Prussian blue stain. However, the iron would not be found in a ring surrounding the nucleus, but throughout the cytoplasm of the cell. The Prussian blue stain demonstrates the presence of iron or hemosiderin in erythroblasts (sideroblasts), erythrocytes (siderocytes) and histiocytes (tissue macrophage). Segmented neutrophils and myelocytes would not be positive in this stain, as iron is incorporated in hemoglobin in the production of erythrocytes. Histiocytes will stain positive after engulfing iron particles. Question Difficulty: Level 2

What is the cell indicated by the arrow in this Prussian blue stain? Ringed sideroblast Siderocyte Segmented Neutrophil Myelocyte

Plasma Cell Plasma cells are fully differentiated B lymphocytes, which are normally not seen in the peripheral blood, but are normally present in small numbers in the bone marrow. Plasma cells are 14-20 µm in diameter. They are characterized by an eccentric nucleus, a prominent perinuclear halo, and abundant dense cytoplasm. If seen in large numbers in peripheral blood they would indicate plasma cell leukemia, which is an advanced stage of multiple myeloma. Basophilic lymphocyte (variant or reactive lymphocyte) can be up to 30µm in diameter. The nucleus is enlarged and may be lobulated. The cytoplasm is an intensely blue color and is abundant and may be foamy or vacuolated. Small lymphocytes are 6-9 µm in diameter with a 4:1 to 3:1 nulcear to cytoplasmic ratio. The nucleus is typically round with a very dense, clumped chromatin pattern. The scanty cytoplasm is a light blue color. Metamyelocytes are 10-18 µm in diameter with a 1:1 nuclear to cytoplasmic ratio. The nucleus is indented with no nucleoli and a clumped chromatin pattern. The pink cytoplasm may contain fine specific granules. Question Difficulty: Level 4

What is the cell indicated by the arrow in this illustration? Basophilic lymphocyte Plasma Cell Small Lymphocyte Metamyelocyte

Smudge cell The cell in this image is a smudge cell. Smudge Cells (bare nuclei) are the neoplastic cells in chronic lymphocytic leukemia. They are more fragile than normal lymphocytes and have a tendency to burst open when making a slide. Hairy cells have hair-like projections and are found in hairy cell leukemia. Foam cells, which can be found in Niemann-Pick disease, have eccentric nuclei and globular cytoplasmic inclusions. Blast cells, which can be found in acute leukemias and other neoplastic disorders, are intact cells with a large nucleus and large nucleus to cytoplasmic (N:C) ratio. The nucleus of a blast typically has nucleoli. Question Difficulty: Level 3

What is the cell indicated by the arrow in this illustration? Hairy cell Smudge cell Foam cell Blast

Ringed sideroblast The Prussian blue stain is commonly used to stain iron. The arrow in the image is pointing to a ringed sideroblast. When a red cell precursor contains too much iron, the siderotic granules form a ring around the nucleus. If siderotic granules form a ring around at least half the periphery of the nucleus of a nucleated red blood cell, the cell is referred to as a ringed sideroblast. Ringed sideroblasts can be seen in sideroblastic anemia, myelodysplastic syndromes, and refractory anemia. Reticulocytes are visualized on supravital stains (new methylene blue) to stain the residual RNA in the cytoplasm. Megakaryocytes are the precursors of platelets and are present on the bone marrow smear using Wright-Giemsa stain, not Prussion blue stain. Plasma cells may be seen on a bone marrow smear using Wright-Giemsa stain. The cytoplasm of plasma cells have a high RNA content, not iron. Question Difficulty: Level 2

What is the cell that is indicated by the arrow in this Prussian-blue stained bone marrow smear? Ringed sideroblast Reticulocyte Megakaryocyte Plasma cell

Granular cast The image below depicts a granular cast. Granular casts are usually indicative of renal disease. These casts are composed of a protein matrix with degraded cellular material. Hyaline casts generally appear as colorless, homogeneous, and transparent with rounded ends. They can also be seen as a result of dehydration, after diuretic therapy, in renal disease, and transiently as a result of exercise. Waxy casts are a bit more refractile that other casts and they commonly have squared-off ends. They are present in patients with severe renal failure, and can be due to allograft rejection. Red blood cells (RBCs) can be identified within the matrix of the cast. The identification of the cast as a red blood cell cast is supported by the appearance of RBCs outside of the cast. Question Difficulty: Level 3

What is the element indicated by the arrow in this image? Hyaline cast Waxy cast Granular cast Red blood cell cast

Chediak-Higashi Image A shows a white blood cell containing the intracytoplasmic inclusions characteristic of Chediak-Higashi anomaly. Ocular and cutaneous albinism, increased susceptibility to pyogenic infections, abnormal granules in neutrophils, and a bleeding tendency are all prominent findings in Chediak-Higashi anomaly. May Hegglin anomaly has Dohle body-like inclusions in the neutrophils, eosinophils and monocytes. Platelets are decreased with poor granulation and are abnormally large. Patients with May Hegglin anomaly may exhibit bleeding tendencies, depending on the degree of thrombocytopenia present. Pelger-Huet anomaly has mature neutrophils with heavy chromatin clumping. The nuclear shape resembles a dumbbell (pince-nez form). This abnormality is seen with abnormal nucleic acid metabolism. Alder-Reilly inclusions are precipitated mucopolysaccharides that appear as purple-red particles in neutrophils, eosinophils and basophils. These inclusions are commonly seen in genetic mucopolysaccharidosis, Hurler's and Hunter's syndromes. Question Difficulty: Level 8

What is the most likely clinical condition in which the cell in the image A would be present in increased numbers? Chediak-Higashi May-Hegglin Pelger-Huet Alder-Reilly

Abetalipoproteinemia The red cells are acanthocytes, which are associated with lipid disorders, such as abetalipoproteinemia. Acanthocytes have multiple thorny, spike-like projections that are irregularly distributed around the cell membrane. Myelofibrosis is associated with tear drop cells. Tear drop cells resemble tear drops. The distinct shape forms as red blood cells squeeze through the fibrous materials when leaving the bone marrow and entering the peripheral blood circulation. Uremia is associated with burr cells. Burr cells can also be an artifact of smear preparation. Burr cells have one or more spiny projections from the cellular membrane. The projections are uniformly shaped. In disseminated intravascular coagulation (DIC), schistocytes are common. Schistocytes are small irregularly shaped fragments of erythrocytes. Question Difficulty: Level 7

What is the most likely clinical condition responsible for the red cell morphology indicated by the arrow? Myelofibrosis Uremia Disseminated intravascular coagulation Abetalipoproteinemia

Barr body The morphology noted in the image is a Barr body. A Barr body is a small appendage, usually round, connected to the nucleus by a chromatin strand. Barr bodies are usually observed only on peripheral blood smears from females. Döhle bodies are large, light blue inclusions in the cytoplasm of neutrophils that may be present along with toxic granulation. Auer Rods are needle-like inclusions found in blasts that are a diagnostic finding in AML. Toxic Granulation is pronounced, medium to large granules scattered throughout the cell. Toxic granulation may be present in infection, toxemia of pregnancy, or vasculitis. Question Difficulty: Level 3

What is the name of the structure that is indicated by the arrow in the image from a Wright-Giemsa stained smear? Döhle body Auer rod Barr body Toxic granulation

Acanthocyte Acanthocytes have blunt spicules that are irregularly distributed around the cell. Acanthocytosis is most often associated with abnormalities of the RBC membrane lipids and are seen in conditions such as abetalipoproteinemia and liver disease. There is also one echinocyte, or burr cell, present in this image at the bottom; however, this is not the predominant abnormal morphology type. Burr cells are spiculated RBCs with short, equally spaced projections over the entire surface. Ovalocytes are oval shaped RBC's. Schistocytes are fragments of RBC's. Question Difficulty: Level 5

What is the predominant abnormal RBC shape seen in this illustration? Burr cell Acanthocyte Ovalocyte Schistocyte

Hyposegmentation of the nucleus The morphology indicated by the cell in this image is hyposegmentation. This neutrophil, would normally have 3-5 lobes; however, in this case the nucleus has not segmented. This morphology is typical of a homozygous-inherited Pelger-Huet anomaly. Hypersegmentation of the nucleus is defined as more than five lobes or nuclear segments. Toxic vacuolation are membrane enclosed circular structures in the cytoplasm of white blood cells. Toxic vacuoles can be found in cases of bacterial infections. Cells with toxic granulation have prominent dark granules in the cytoplasm. These granules could be fine or heavy and are seen in band and segmented neutrophils and monocytes. Question Difficulty: Level 5

What morphological change is present in this image? Hypersegmentation of the nucleus Hyposegmentation of the nucleus Toxic vacuolation Toxic granulation

Normocytic, normochromic The red blood cells depicted in this image display both normal size and hemoglobin content. These cells would be described as normocytic, normochromic. To be classified as hypochromic, the central pallor would be greater than one third of the cell. These cells are between 6-8 micrometers, which is the normal red blood cell size. Macrocytic cells would be larger and microcytic cells would smaller. Polychromatophilic red blood cells are typically larger than normal cells and have a bluish tinge due to the residual RNA in the cytoplasm. Question Difficulty: Level 2

What red blood cell morphology is pictured here? Normocytic, normochromic Microcytic, hypochromic Microcytic, normochromic Macrocytic, polychromatic

RBC cast RBC casts may appear as brown to almost colorless. Red cells can clearly be seen within the cast. This type of cast is diagnostic of glomerular disease or intrarenal bleeding. WBC casts are seen in renal infection or inflammation such as pyelonephritis. The identification of the cast as a WBC cast is supported by the appearance of WBCs within the cast. Waxy casts are a bit more refractile that other casts and they commonly have squared-off ends. They are present in patients with severe renal failure, and can be due to allograft rejection. Granular casts are usually indicative of renal disease. These casts are composed of a protein matrix with degraded cellular material. Question Difficulty: Level 3

What type of cast is shown in the illustration? WBC cast RBC cast Waxy cast Granular cast

Bacillus cereus Bacillus cereus colonies are characteristically spreading, gray-white, and beta hemolytic, with a "frosted glass" appearance. Burkholderia pseudomallei also produces spreading colonies, but they are more wrinkled in appearance and without beta hemolysis. Listeria monocytogenes produces small, round, translucent colonies that characteristically have a narrow zone of beta hemolysis, noted if colonies are removed. The nocardioform bacteria, Streptomyces (formerly greseus) anulatus, produces opaque, chalky, white colonies. This species can also be suspected if the colonies have a pungent, musty basement odor. Question Difficulty: Level 5

Which bacterial species is most likely represented by the spreading, gray-white, beta-hemolytic colonies with a "frosted glass" appearance as illustrated in the photograph? Burkholderia pseudomallei Listeria monocytogenes Bacillus cereus Streptomyces anulatus

Chediak-Higashi syndrome Chediak-Higashi syndrome is a rare autosomal recessive condition. It is characterized by the presence of large peroxidase positive lysosomes in most cells of the body including neutrophils. Pelger-Huet anomaly is a benign condition that is characterized by hyposegmented (bilobed or round nuclei) neutrophils that have normal function. Theses neutrophils are referred to as pince-nez cells. Dohle bodies are light gray blue bodies found in the cytoplasm of neutrophils and eosinophils. They are aggregates of rough endoplasmic reticulum and are associated with severe bacterial infections. Toxic granulation are neutrophilic granules that are larger and darker staining than normal. They are present in various infectious states and can be found in combination with dohle bodies. Question Difficulty: Level 3

Which disease/condition can be indicated by the morphology displayed in the white blood cell to the right? Chediak-Higashi syndrome Pelger-Huet anomaly Dohle bodies Toxic granulation

High myeloid to erythroid (M:E) ratio -- Many WBC precursors, few RBC precursors, Megakaryocyte present The myeloid to erythroid (M:E) ratio is ratio between all the granulocytes and their precursors and all nucleated red cell precursors. This is a bone marrow with only a few late RBC precursors and many WBC precursors. This is considered a trilinear marrow and will have a high M:E ratio. There is a megakaryocyte present in the lower right corner of the image. Question Difficulty: Level 8

Which of following descriptors would apply to the bone marrow displayed in the image to the right? High myeloid to erythroid (M:E) ratio -- Many WBC precursors, few RBC precursors, Megakaryocyte present Inverted or Low M:E ratio -- Few WBC precursors, many RBC precursors, Megakaryocyte present Normal myeloid to erythroid (M:E) ratio -- Many WBC precursors, many RBC precursors, Megakaryocyte present High myeloid to erythroid (M:E) ratio -- Many WBC precursors, Many RBC precursors, Megakaryocyte present

Howell-Jolly bodies Howell-Jolly bodies appear on a Wright-stained peripheral blood smear as round, smooth, almost pyknotic, dark-purple staining bodies ranging in size from 0.5 to 1.0 micron in diameter and usually occurring singly in erythrocytes. Heinz bodies are formed from denatured globin and do not stain with Wright's stain. They can be identified with a supravital stain such as New Methylene Blue and will appear as single or multiple bodies bound to the membrane. Basophilic stippling will present as blue or purple coarse or fine granules distributed evenly throughout the cell. Pappenheimer bodies will appear as light blue, fine, irregular granules in clusters, often at the periphery of the cell. Question Difficulty: Level 2

Which of the erythrocyte inclusions listed below would appear on a Wright-stained peripheral blood smear as round, smooth, almost pyknotic, dark-purple staining bodies ranging in size from 0.5 to 1.0 micron in diameter and usually occurring singly in erythrocytes? Howell-Jolly bodies Heinz bodies Basophilic stippling Pappenheimer bodies

Myeloblast Myeloblasts typically have a high N:C ratio, round to oval nuclei, fine chromatin with nucleoli present, and a light blue cytoplasm. In this case, there is an Auer rod present in the cytoplasm, which indicates the blast is of neoplastic origin. Auer rods are mainly seen in myeloblasts and present in many subgroups of acute myeloid leukemia; their presence excludes a diagnosis of acute lymphoblastic leukemia. The chromatin of myelocytes and metamyelocytes is much more condensed; nucleoli are rarely seen in myelocytes and absent in metamyelocytes. Fine, pinkish-lavender specific granules are seen in both myelocytes and metamyelocytes. The nucleus of a metamyelocyte is also more indented, and often resembles a kidney bean shape. Monocytes may have a round, oval, or kidney-shaped nucleus, but frequently have a horseshoe-shaped (indented) nucleus. The chromatin pattern is typically lacy and nucleoli are absent. The blue-gray cytoplasm has a "ground-glass" appearance due to fine azure granules. Cytoplasmic vacuoles may be present. Question Difficulty: Level 7

Which of the following cells is seen in the photomicrograph? Myeloblast Myelocyte Metamyelocyte Monocyte

Autoimmune hemolytic anemia The small, spherical, dense red blood cells shown are spherocyte, lacking central pallor. These cells are highly associated with hemolytic anemias. The spherocytes shown in this image are not indicative of hereditary spherocytosis, as the spherocytes do not predominate the peripheral blood field. The microcytic red cells of iron deficiency anemia and thalassemia are pale staining and contain central pallor. The red blood cells in megaloblastic anemia are associated with macrocytes or large ovalocytes. Question Difficulty: Level 6

Which of the following conditions can be associated with the red blood cell morphologies shown in this image? Autoimmune hemolytic anemia Iron deficiency Beta thalassemia Megaloblastic anemia

Abetalipoproteinemia The correct response is abetalipoproteinemia. While the majority of red blood cells in abetalipoproteinemia are acanthocytes, the peripheral blood smear that is pictured here contains only an occasional acanthocyte (the cell that is tagged by the arrow), an amount not consistent with abetalipoproteinemia. Acanthocytes in lesser numbers are found in advanced liver disease, in newborn hepatitis, and following splenectomy when there is reduced removal of these poikilocytes. Question Difficulty: Level 6

Which of the following conditions is NOT consistent with this peripheral blood picture? Abetalipoproteinemia Alcoholic cirrhosis with hemolytic anemia Hepatitis of the newborn Post-splenectomy

G6PD deficiency The correct response is G6PD deficiency. These atypical erythrocytes are bite cells which are associated with Heinz body formation. Note the multiple nibbles in many of the erythrocytes. Heinz bodies represent the presence of denatured hemoglobin associated with G6PD deficiency. Schistocytes, keratocytes, and tear drop cells are more common in microangiopathic anemia. The atypical RBCs found in abetalipoproteinemia are acanthocytes. The predominant abnormal red cells in thalassemia are target cells (codocytes). Question Difficulty: Level 5

Which of the following conditions is associated with the defective erythrocytes that are indicated by the arrows in this image? G6PD deficiency Microangiopathic hemolytic anemia Abetalipoproteinemia Beta thalassemia

Megaloblastic anemia The white blood cell in the image is a hypersegmented neutrophil. A neutrophil, when mature, will have a nucleus with between 2 and 5 segments. A hypersegmented neutrophil has a nucleus with more than 5 segments. This is a common finding in megaloblastic anemias. There are no WBC abnormalities associated with hemolytic anemia, iron deficiency anemia, or sickle cell anemia. Schistocytes and spherocytes are characteristic RBC findings in Hemolytic anemia. Iron deficiency anemia is characterized by microcytic and hypochromic RBC's. Sickle cells, also known as drepanocytes, are the characteristic finding in sickle cell anemia. Question Difficulty: Level 3

Which of the following conditions is frequently associated with the white blood cell shown? Hemolytic anemia Iron deficiency anemia Megaloblastic anemia Sickle cell anemia

May-Hegglin anomaly May-Hegglin anomaly is a rare, autosomal dominant trait in which granulocytes contain inclusions of RNA and giant platelets. Patients experience no symptoms other than occasional bleeding issues due to low platelet counts. Toxic changes, such as toxic granulation and vacuoles, may be observed in neutrophils with sepsis. Chediak-Higashi syndrome is a rare autosomal recessive disorder causing primary and secondary neutrophilic granules to fuse, inhibiting their function. Giant platelets are not typically seen. Alder-Reilly anomaly is an inherited condition leading to large purple granules in all leukocytes. Question Difficulty: Level 3

Which of the following conditions may produce the findings indicated by the arrows in the image on the right? Sepsis May-Hegglin anomaly Chediak-Higashi syndrome Alder-Reilly anomaly

Transfusion dimorphism There are two populations of red blood cells present. The microcytic, hypochromic population is suggestive of iron deficiency anemia. Interspersed among these cells is a second population of normocytic, normochromic red blood cells, suggesting transfusion dimorphism. Two separate peaks (populations) should be observed on the red blood cell histogram generated by the hematology analyzer. In hereditary spherocytosis, spherocytes are seen interspersed among normocytic, normochromic red blood cells. Polychromatophilic erythrocytes are often noted. In lead poisoning, a dual population of hypochromic and normochromic red blood cells may be present; however, poikilocytosis and red blood cell inclusions, notably basophilic stippling, are usually present, as well. Folic acid deficiency leads to a macrocytic, normochromic anemia. Question Difficulty: Level 6

Which of the following conditions/findings is most likely associated with the peripheral blood picture in the photomicrograph? Hereditary spherocytosis Lead poisoning Transfusion dimorphism Folic acid deficiency

Blastomyces dermatitidis The dimorphic fungi demonstrate a mycelial or mold phase when grown at room temperature (20-25° C) and yeast or tissue phase when grown at 35-37oC. The mold phase of Blastomyces dermatitidis is characterized by spherical or oval conidia, each supported by an individual conidiophore and are described as resembling a "lollipop". The mold form of Coccidioides immitis is characterized by the production of rectangular shaped arthroconidia that appear alternate staining because each cell is separated by an empty or dysjunctor space. When mature, each arthroconidium is swollen centrally, giving a barrel-like appearance. Spiked or echinulate macroconidia are characteristic of the mold form of Histoplasma capsulatum. The mold form of Sporothrix schenckii is recognized by the production of tiny microconidia that are arranged around the tip of a delicate conidiophore resembling petals on a daisy flower. Question Difficulty: Level 5

Which of the following dimorphic molds produces spherical or oval conidia, each supported by an individual conidiophore ("lollipop") as represented in the image on the right? Blastomyces dermatitidis Coccidioides immitis Histoplasma capsulatum Sporothrix schenckii

Frame C- primary myelofibrosis Frame C is a circulating nucleated red blood cell (rubricyte). Nucleated red blood cells are not normally found in the peripheral blood. In primary myelofibrosis, the bone marrow is filled with fibrous tissue so the body resorts to extramedullary hematopoiesis. This results in teardrop RBCs, nucleated RBCs and immature myeloid cells in the peripheral blood. Frame A is a reactive or variant lymphocyte. These are found in the peripheral blood in infectious mononucleosis or other viral infections. Lymphoblasts are the cells associated with acute lymphoblastic leukemia. Frame B is a plasma cell. These cells are found in the peripheral blood of a patient with plasma cell leukemia. Polycythemia vera presents with increased numbers of normal mature RBCs in the blood. Frame D is a monocyte. These cells are involved in the body's inflammatory response and phagocytic engulfment of foreign particles. The classic cell associated with infectious mononucleosis is a reactive or variant lymphocyte. Question Difficulty: Level 8

Which of the following is a correct pairing of cell type in the image and a disease state associated with that type of cell? All cells are from a Wright stained peripheral blood smear. Frame A - acute lymphoblastic leukemia Frame B- polycythemia vera Frame C- primary myelofibrosis Frame D- infectious mononucleosis

Seen only in women The small drumstick-like nuclear extension (Barr body) marked by the blue arrow is a chromatin mass which may represent a chromosomal remnant. These nuclear appendages are found in normal XX females, but would not be present in normal XY males. If such an appendage is found in a phenotypic male, Klinefelter's syndrome (XXY male) may be identified clinically. The appendage has a "drumstick" morphology. Dwarfism has nothing to do with the appearance of a Barr body. Question Difficulty: Level 5

Which of the following is true of the nuclear appendage seen in this image? Seen only in women Seen only in men Seen in both sexes Seen in dwarfs only

Bacillus anthracis All of the species listed are gram positive bacilli as shown in the image. However, the image also shows spores within the bacilli. These are what appear to be clear areas in the bacilli. The spores do not gram stain, a spore stain is needed to be able to view the spores specifically, so they show up as clear areas. Out of the options, Bacillus anthracis is the only organism that produces spores. Additionally, the spores are very large with square ends and seen in chains, very characteristic for Bacillus species. Bacillus species are the aerobic spore forming organisms and Clostridium are the anaerobic spore forming organisms. Corynebacterium diphtheriae is a gram positive bacillus that is pleomorphic and can look club shaped or diptheroid. The bacilli are typically arranged in parallel rows and can show "V" and "L" formations. They do not produce spores. Listeria monocytogenes is a gram positive bacillus that is straight and found singly or in pairs. They can also be seen in short chains. They do not produce spores. Erysipelothrix rhusiopathiae is a gram positive bacillus that is long and thin. Typically bacilli are in short chains or "V" shapes. They do not produce spores. Question Difficulty: Level 3

Which of the following organisms would give the gram stain microscopic results seen in this image? Bacillus anthracis Corynebacterium diphtheriae Listeria monocytogenes Erysipelothrix rhusiopathiae

Cabot ring Cabot ring is not shown. Cabot ring is a red-violet inclusion that is oval or figure-eight shaped. It consists of nuclear fragments or mitotic spindle fibers. In Frame A are Pappenheimer bodies. They appear as tiny blue-staining bodies in Wright-stained smears (confirmed with an iron stain), often in pairs and more commonly at the periphery of the cell than found in the photograph. They are characteristically found in sideroblastic anemia. The erythrocyte marked by a blue arrow in Frame B displays very finely granular basophilic stippling, that may be found in autoimmune hemolytic anemias. The red blood cell inclusion in Frame C is a plasmodium ring form of Falciparium malaria and associated with recurrent fever. In Frame D are erythrocytes containing Howell-Jolly bodies remaining in the circulation after splenectomy. Question Difficulty: Level 7

Which of the following red cell inclusions is not identified in the frames of photographs? Basophilic stippling Pappenheimer bodies Malaria parasite Cabot ring

Ringed sideroblast The cell indicated by the arrow is a ringed sideroblast. If siderotic granules form a ring around at least half the periphery of the nucleus of a developing red blood cell, the cell is referred to as a ringed sideroblast. This is due excess ferritin aggregates and mitochondrial iron loading, and is seen in sideroblastic anemia and other conditions involving ineffective erythropoiesis. A siderocyte also has excess iron in the cytoplasm and is seen upon Prussian blue staining, but the term refers to a mature RBC with iron, as compared to sideroblast which is an immature or developing RBC. A sideroblast is a developing (immature) RBC with iron deposits as well, but they are throughout the cell and do not ring around the nucleus. Basophilic stippling is the name given to the ribosomal/RNA inclusions seen in a mature RBC; unlike the above three examples, they can be seen on a Wright's stain. Question Difficulty: Level 4

Which of the following terms most accurately identifies the cell indicated by the arrow in this bone marrow slide that was stained with Prussian blue iron stain? Siderocyte Sideroblast Ringed sideroblast Basophilic stippling

Unable to determine cause of infection Unble to determine the cause of infection is the correct answer because organisms that resemble Neisseria gonorrhoeae may reside in the female genital tract. Look-alike organisms include Acinetobacter baumanii and Capnocytophaga ochracea, which are both oxidase negative. Two other look-alikes, Kingella kingae and Moraxella catarrhalis, are oxidase positive and may be difficult to distinguish from Neisseria gonorrhoeae which also is oxidase positive. Neisseria gonorrhoeae infection is incorrect because normal vaginal and rectal flora consist of gram-negative coccobacilli that can be easily misidentified as Neisseria gonorrhoeae. Therefore, culture or molecular methods are required in females to recover and identify the presence of Neisseria gonorrhoeae. Moraxella species infection is incorrect because Moraxella species is part of the normal vaginal and rectal flora and are gram-negative coccobacilli that can be easily misidentified as Neisseria gonorrhoeae. Trichomonas vaginalis infection is incorrect because before Trichomonas vaginalis is reported, the organism must be viewed being motile by anterior flagella and an undulating membrane. Typically, Trichomonas vaginalis is recovered via a saline wet mount of vaginal specimens. Question Difficulty: Level 5

A 25-year-old female presented in the emergency room with an acute urethral discharge of two days duration. The image to the right shows the Gram stained smear that was obtained. Many polymorphonuclear leukocytes and intracellular and extracellular gram-negative diplococci were observed. Based on the clinical history and the Gram stain observation, what diagnosis can be made?. Neisseria gonorrhoeae infection Moraxella species infection Unable to determine cause of infection Trichomonas vaginalis infection

Streptobacillus moniliformis A history of the sudden onset of fever, headache and muscle aches following the bite of a rat or mouse is class for "rat bite fever", also known as "Haverhill fever", named after the Massachusetts town where an outbreak occurred in the early 1970's. This infection is caused by Streptobacillus moniliformis, a fastidious, pleomorphic, gram-negative bacillus the cells of which may appear filamentous, bulbous or coiled. Yersinia pestis, the causative agent of plague, may result in septicemia after the bight of a rat, mouse, or other rodent. Plague is localized to the four corners region of the United States and less than a dozen cases are reported each year. The gram stain of Y. pestis shows small Gram-negative coccobacilli. Erysipelothrix rhusiopathiae may also result in septicemia; however, infections are most often seen in fish handlers, farmers, slaughterhouse workers, food preparation workers, and veterinarians. The disease is zoonotic, but contracted more often from fish and domestic animals such as sheep, rabbits, cattle, and turkeys. Gram stain shows gram positive bacilli. Spirilum minus is also causes rat-bite fever, but is primarily seen in Asia. The disease is referred to as sodoku. The Gram stain shows thick, spiral, Gram negative bacilli. Question Difficulty: Level 7

A 30 year old laboratory worker in New York, doing extensive research on laboratory mice, developed sudden onset of fever, chills, headache and muscle aches. He remembered being bitten by one of the mice about a week previously, although the skin wound healed without incidence. A direct gram stain from the laboratory worker is shown and includes the microrganism causing disease. Yersinia pestis Erysipelothrix rhusiopathiae Streptobacillus moniliformis Spirillum minus

Listeria monocytogenes The relationship between Listeria monocytogenes and milk and milk products (when unpasteurized) is well known. Pregnant women and immunosuppressed persons are particularly susceptible to infection with L. monocytogenes following ingestion of various contaminated foods, namely milk and milk products, undercooked chicken, turkeys, and other meats and vegetables. The bacterial colonies show a slight beta hemolysis that may simulate Streptococcus agalactiae; however, the appearance of Gram positive bacilli in Gram stains separate these two species. Infections with Brucella species also are related to ingestion of unpasteurized milk and milk products; however, the colonies are not beta hemolytic and the bacterial cells are Gram negative. Leuconostoc mesenteroides, a Gram positive coccobacillus also associated with the dairy and pickling industry and also a rare cause of meningitis and other human infections, cannot be totally ruled out although is much less likely. The colonies are not beta hemolytic and the bacterial cells are more coccus-like in shape. L. mesenteroides is vancomycin resistant. Question Difficulty: Level 4

A 30-year-old Hispanic pregnant female developed fever and signs and symptoms of meningitis following ingestion of cheese sent by relatives in Mexico. The colonies recovered from a positive blood culture is shown in the upper photograph; the microscopic features in the lower photograph. The most likely identification is: Streptococcus agalactiae Listeria monocytogenes Brucella melitensis Leuconostoc mesenteroides

Group F The tiny colonies seen in the upper photograph are surrounded by a narrow zone of beta hemolysis. The lower photomicrograph confirms that the isolate is a streptococcus. The small size of the colonies and the butter scotch odor are clues to the identification of Streptococcus anginosus (S. milleri in the European literature), which characteristically carries the F antigen. S. anginosus is one of the more common isolates from hepatic abscesses, although Group G would be a close contender. The bacterial colonies of the other streptococci listed are considerably larger after 36 hours incubation and the zones of hemolysis are much wider and more distinct. Question Difficulty: Level 7

A 30-year-old man with chronic persistent hepatitis developed an abscess in the right hepatic lobe. A needle aspiration revealed purulent material. The small colonies shown in the upper photograph were isolated after 36 hours incubation at 35°C. They emitted a butter scotch odor. The lower photomicrograph reveals the gram stain features. The antigen most likely carried by this isolate is: Group A Group B Group G Group F

Brucella abortis The undulant fever pattern described in the clinical history and the delayed growth in both blood culture media and chocolate agar are most consistent with Brucella species. The appearance of the colonies on the chocolate agar plate is consistent and the Gram stain reveals tiny, coccal organisms. The clinical history and the cultural characteristics are most consistent with Brucella abortis among the choices available. The Gram stain of Neisseria cinerea shows Gram negative diplococci with adjacent ends flattened, which is not seen in the image. Neisseria cinerea grows equally well on blood agar and on chocolate agar, Haemophilus aphrophilus grows equally well on blood agar as on chocolate agar. The bacterial cells of H. aphrophilus are more distinctly bacillary than are seen here. Moraxella catarrhalis also grows well on blood agar, but its Gram stain shows gram negative diplococci with adjacent ends flattened. Question Difficulty: Level 6

A 33-year-old livestock farmer, native to central Illinois, gave a one month history of diurnal fever, peaking at in the evening and during the night, but subsiding during the daytime. He also complained of muscle aches and easy fatigability. After several negative blood cultures, an organism was finally recovered after 9 days incubation. The colonies shown in the upper photograph appeared on chocolate agar after 48 hours incubation in CO2. Growth was poor on blood agar. The microscopic morphology of a Gram stain prepared from one of the colonies is shown in the lower photomicrograph. The most likely identification is: Moraxella catarrhalis Brucella abortis Haemophilus aphrophilus Neisseria cinerea

Plasmodium falciparum Plasmodium falciparum is the correct response. Distinctive is the large sickle-form gametocyte seen in the image. Also characteristic is the normal size of the erythrocytes, many of which have been infiltrated with small "ring forms", in many cases more than one per cell. Also noted in a few erythrocytes is the position of tiny ring forms immediately beneath the outer cell membrane, in what is known as an "appliqué" form. Plasmodium vivax is an incorrect response. Early ring forms, as observed within scattered erythrocytes, may be initially small but characteristically enlarge with light pinkish staining and delicate stippling in the form of "Schuffner's dots". The nucleus enlarges with a gently flowing cytoplasm that with further development may divide in the formation of an early schizont. Plasmodium malariae is an incorrect response. The early ring forms of P. malariae may resemble those of other plasmodium species, but soon can be distinguished as the developing trophozoites bridge to the borders of the infected erythrocyte in a "band" form. The infected erythrocytes are neither enlarged nor pale, and Schuffner's dots do not develop. Plasmodium ovale is an incorrect response. The ring forms are uncommonly observed in clinical cases of human malaria, and in early development are similar to those of P. falciparum and P. vivax. Distinctive is the enlarged oval shape of the infected erythrocytes, some with a fimbriated appearance and enlargement of the trophozoites with fine granules in the early form of Schuffner's dots. Question Difficulty: Level 5

A 40-year-old business man developed intermittent spiking fevers one week following a trip to Western Africa. The Wright-stained peripheral blood smear as illustrated in the image was observed. Based on the morphology of the erythrocytes and the heavy invasion with ring form trophozoites, the diagnosis of malaria could be made. With particular focus on the sickle-form gametocyte, which Plasmodium species is represented by this peripheral blood smear? Plasmodium vivax Plasmodium falciparum Plasmodium malariae Plasmodium ovale

Abiotrophia defectiva The images illustrate an organism that requires growth factors provided by the Staphylococcus shown in the streak preparation. Slow-growing Streptococcus-like species variously known as "satelliting," "nutritionally dependent," or "thiol requiring" need thiol compounds, such as cysteine or the active form of vitamin B6 (pyridoxal), added to culture media to promote growth. These compounds are synthesized by Staphylococcus species and other bacterial species, so that the nutritionally dependent Abiotrophia defectiva may appear as satellite colonies. Although the other bacterial species listed may appear as gram-positive cocci in chains and may cause endocarditis, none are thiol-dependent and would appear as a more diffuse growth on the blood agar surface, not confined to the area adjacent to the Staphylococcus streak shown in the upper image. Question Difficulty: Level 8

A 40-year-old man with a prosthetic valve developed intermittent bouts of low grade fever. A changing cardiac murmur suggested the possibility of endocarditis; however, repeat blood cultures over a two week period were all negative. Bacteria resembling those seen in the lower image were finally seen in Gram stain of a positive bottle. Colonies were recovered when broth was subcultured to a blood agar plate with a staph streak, as shown in the upper image. What is the most likely bacterial species? Streptococcus mitis group Enterococcus faecalis Abiotrophia defectiva Streptococcus bovis

Actinobacillus actinomycetemcomitans The correct answer is Actinomyces israelii. The case description given above is a classic description of "lumpy jaw", the most common cause of which is Actinomyces israelii. Branching, gram positive filaments against a background of neutrophils as seen in the photograph is characteristic of the cell morphology of this bacterium. Actinobacillus actinomycetemcomitans is often found in conjunction with A. israelii, but the bacterial cells are gram negative rather than gram positive, of which there is no evidence here. Mycobacterium scrofulaceum causes "scrofula", also an infection of the posterior neck area leading to enlargement of posterior cervical lymph nodes. However, the inflammatory response is more granulomatous than purulent and the bacterial cells do not branch and are acid fast positive. The bacterial cells of Bifidobacterium dentium are gram positive rods that can branch; however, they are much larger than the filaments of A. israelii and are club-shaped on the ends, resembling "dog bones". Bifidobacterium species have only rarely been incriminated in human infections and do not cause "lumpy jaw". Question Difficulty: Level 5

A 49-year-old farmer developed swelling of the neck beneath the left jaw with enlargement of the left posterior cervical lymph nodes. The photograph to the right is representative of a direct gram stain prepared from purulent material aspirated from one of the enlarged lymph nodes. The organism was not acid fast. What is the MOST likely identification? Actinobacillus actinomycetemcomitans Mycobacterium scrofulaceum Actinomyces israelii Bifidobacterium dentium

Spherocytes, nucleated red blood cells, polychromatophylic red blood cells Spherocytes (small round deeply statning red blood cells), nucleated red blood cells (larger, bluish staining cells with a small pyknotic nucleus), and polychromatophylic cells (large, slightly bluish red blood cells) are all seen on this smear. These cells are frequently seen in hemolytic anemias. Acanthocytes are cells with long spikey projections, and are not seen on this smear. Target cells resemble a target and have a red staining center surrounded by an area of pallor. These are also not seen on this smear. Question Difficulty: Level 6

A 49-year-old male with pneumonia was treated with high-dose intravenous penicillin. He became jaundiced with yellow sclera. The image on the right is typical of other fields that were observed on his peripheral blood smear. Since penicillin may, in some individuals, cause autoimmune hemolytic anemia, the clinician requested a direct antiglobulin test (DAT) be performed. The DAT was positive, indicating that antibodies to the drug were produced, which then attached to the drug on the surface of the red cells. Hemolysis occured due to the drug-induced antibody attachment, leaving the patient with various abnormal red blood cell morphologies. Which of the following cell types would you report for this patient? Acanthocytes, nucleated red blood cells, polychromatophylic red blood cells Burr cells, spherocytes, polychromatophylic red blood cells Target cells, acanthocytes, polychromatophylic red blood cells Spherocytes, nucleated red blood cells, polychromatophylic red blood cells

Ethylene glycol The crystals that are seen in the urine are monohydrate calcium oxalate crystals. Oxalic acid, a byproduct of ethylene glycol (antifreeze) metabolism, combines with calcium in the body to form monohydrate calcium oxalate crystals, as shown in the accompanying image. Accidental poisoning with ethylene glycol occurs most of the times in young children and pets. This is because it is a sweet tasting compound and if left uncovered in an easily reachable place it can be very tempting to consume. Question Difficulty: Level 4

A 62-year-old man drank an unknown liquid in a suicide attempt, and his urine contained crystals similar in shape to those shown in this image. This man MOST likely ingested: Methanol Isopropanol Ethylene glycol Ethanol

Streptococcus pneumoniae The clinical setting of lobar pneumonia in an elderly patient is most likely associated with Streptococcus pneumoniae. The mucoid, alpha hemolytic colonies seen in the blood agar plate and the gram-positive diplococci seen in the sputum specimen are virtually confirmatory. Enterococcus faecalis can produce a gram stain similar to that illustrated; however, the colonies are not mucoid and lobar pneumonia by this species would be less likely. Klebsiella pneumoniae can appear as mucoid colonies on blood agar and can cause lobar pneumonia similar to that described; however, the bacterial cells are gram negative bacilli. Staphylococcus intermedius would more likely cause a necrotizing bronchopneumonia, the colonies are not mucoid and the cocci arrange in loose clusters or tetrads rather than pairs. Question Difficulty: Level 4

A 67-year-old man was seen in the emergency room complaining of cough, fever, and piercing right posterior chest pain. X-ray of the chest revealed consolidation of the right middle lobe of the lung. A sputum culture grew the bacterial species shown in the upper photograph. The lower photomicrograph illustrates a gram-stain of the sputum specimen. The most likely cause of the pneumonia is: Klebsiella pneumoniae Enterococcus faecalis Staphylococcus intermedius Streptococcus pneumoniae

Acute Myeloid Leukemia (AML) The arrows are pointing to Auer rods. The presence of Auer rods are highly indicative of myeloid blasts. Auer rods are not present within lymphoblasts, but can occasionally be found in monoblasts. 40% of the of AML cases occur in patients 60 years or older. These patients can also have hemorrhagic effects, such as easy bruising, epistaxis (nose bleeds) and petechiae (small red-purple spots on the skin) due to thrombocytopenia (decreased platelet count). Immature myeloid blasts do not offer protection from infections as mature leukocytes do. This would explain the frequent infections seen in this patient. In this case, the only condition that matches the symptoms and blood cells out of the choices above would be AML. In ALL there are the presence of blasts in the peripheral blood, however, they would not contain Auer rods. Cytochemical stains or flow cytometry can be used to differentiate between lymphoblasts and myeloblasts. The key finding in ALL would be the presence of lymphoblasts. In CLL the prominent cell finding is mature lymphocytes, not blasts. PV is a neoplasm of red blood cells. PV is characterized by high red blood cell counts and high hemoglobin levels. White blood cell counts may be elevated in PV with a shift to the left, but myeloblasts and promyelocytes are rare. Question Difficulty: Level 4

A 76-year-old patient experiences frequent infections and bleeding episodes. She is also complaining of pain in her bones and joints. Upon routine exam, her physician orders a complete blood count and differential. The hematology technologist notices many cells appearing similar to the cell in the image to the right. Which condition is this patient most likely suffering from? Acute Myeloid Leukemia (AML) Acute Lymphoid Leukemia (ALL) Chronic Lymphocytic Leukemia (CLL) Polycythemia Vera (PV)

Gram-positive cocci in tetrads and clusters present In reporting out Gram stains, one should not go beyond what objective observation will allow. In this case, bacterial cells are observed, which are spherical and gram-positive. Their arrangement in tetrads and clusters might be helpful to the physician, suggesting a Staphylococcus species. However, one should stop short of naming the genus in an official report, as the large gram-positive cocci in tetrads is also suggestive of Micrococcus species, for which human infections have not been reported. Question Difficulty: Level 1

A Gram stain of serous exudate is shown in the image. What should the tech report to the physician? Gram-positive cocci present Gram-positive cocci in tetrads and clusters present Gram-positive cocci suggestive of Staphylococcus species present Bacteria present

Dimorphic red cell population Dimorphic or bimodal cellular distribution is a term used to describe two circulating red cell populations. One is the patient's basic red cell population while the other is a second population with distinct morphological features. Note the normal lymphocyte for size comparison with the two populations of red blood cells. In addition, the graphic illustration demonstrates two peaks in the red blood cell histogram. Dimorphic red blood cell populations can be found in conditions/situations such as: red blood cell transfusions or hemolytic processes involving a reticulocyte response. This may also occur when patients are given erythropoietin therapy. Cold agglutinins cause rbc agglutination and clusters of cells may appear as a separate larger rbc population on the rbc histogram. It is important to recognize when a population of cells in the peripheral smear is not in context with anticipated laboratory findings and the clinical situation. A normal peripheral smear will demonstrate a unimodal distribution on the rbc histogram. Iron deficiency anemia will typically demonstrate small rbcs (microcytes) thus a low mean cell volume (MCV). There will often be an increased red cell distribution width (RDW) indicating anisocytosis, but there are not two separate populations of rbcs. Aplastic anemia is a consequence of failure the hematopoietic process. All cell lines are affected. Red blood cells are usually normochromic and normocytic with a normal RDW. Question Difficulty: Level 4

A blood smear represented by the photograph was submitted for hematologic review. Based on the erythrocyte morphology and the accompanying histogram, which of the following choices is the most likely situation or condition? Normal smear Iron deficiency anemia Aplastic anemia Dimorphic red cell population

An indwelling catheter The most likely source of the infection is an indwelling catheter. The budding yeasts with pseudohyphae are indicative of Candida species. The staphylococci seen here are in distinct grape-like clusters, most consistent with S. aureus. Either of these species could account for any one of the clinical conditions indicated in this exercise; however, the most likely common source for both organisms would be an indwelling catheter. Catheters are vulnerable to colonization with organisms found on the patient's skin. Both S. aureus and C. albicans have been recovered as normal skin biota. Bacteremia secondary to urinary tract infections are usually caused by a single organism, the most common being Escherichia coli. Lung abscesses may be secondary to a hospital-acquired pneumonia. While mixed infections are common in these types of infections, the most common organisms recovered include S. aureus and gram negative rods such as Pseudomonas aeruginosa, Enterobacter spp., Klebsiella spp., and E. coli. Cellulitis that could result in bacteremia is typically caused by S. aureus, Streptococcus pyogenes, or Streptococcus agalactiae, but not yeast. Question Difficulty: Level 5

A budding yeast with pseudohyphae and clusters of gram positive staphylococci were observed in a Gram stain smear prepared from a positive blood culture. What is the MOST likely source of the infection? Urinary tract An indwelling catheter Lung abscess Subcutaneous cellulitis

Bacterial infection Almost exclusively segmented neutrophils are seen, suggestive of bacterial infection. In general, CSF white cell count would be in the thousands per µL in bacterial meningitis. In fungal infections, yeast form maybe seen in CSF. Fungal meningitis occurs primarily in patients who are immunocompromised. With immune cells (including macrophage) being dysfunctional, CSF white count would not be as elevated, although the usual cellular response against fungal infection is interaction between the antigen-presenting cell and the effector T lymphocytes. In cryptococcal meningitis, for example, CSF white count may be only mildly elevated particularly in patients undergoing "immune reconstruction inflammatory syndrome." Lymphocytes are elevated in viral meningitis. In general, CSF white cell count would be in the hundreds per µL. Malaria parasites infect red cells in circulation, not in CSF. Question Difficulty: Level 2

A cloudy CSF sample has a white count of over 1,000 WBC/µL. The large number of these cells seen in the cytocentrifuged smear in this illustration is suggestive of: Fungal infection Viral infection Malarial infection Bacterial infection

Lymphocytes The cell types which should be included in this report are lymphocytes. In viral meningitis the predominant cells that are seen are lymphocytes. They are also the predominant cells in normal adult cerebrospinal fluid, however in viral meningitis many of the lymphocytes will be reactive or atypical in their appearance. Monocytes are the predominant cells in the CSF of infants. Monocytes will have fine granules and an indented or folded nucleus. They will often spread across the slide and appear larger than lymphocytes, due to the centrifugation caused by the cytospin centrifuge. Blast cells are not normally found in the CSF. They are occasionally seen in patients with acute lymphoblastic leukemia. Blast cells will have fine nuclear chromatin, one or more nucleoli, and a high nuclear:cytoplasmic ratio. Plasma cells are not normally found in the CSF. They could be present in plasma cell leukemia or multiple myeloma due to a traumatic tap or a breakdown in the blood-brain barrier. Plasma cells have a round or oval eccentric nucleus, dark blue cytoplasm, and a clear zone adjacent to the nucleus (hof). Question Difficulty: Level 7

A college student is treated in the hospital for suspected meningitis. Which cells should be identified in the cerebrospinal fluid (CSF) report for the cytospin field that is shown? Monocytes Blast cells Lymphocytes Plasma cellls

Taenia solium Taenia solium is the correct response. These cysts are commonly found in the brain, resulting in a disease called cysticercus. The proglottid as illustrated in the image as presented is longer than wide, and has less than 13 lateral uterine branches that is characteristic of T. solium, as part of the life cycle. T. saginata proglottids, in contrast to those of T. solium, possess more than 13 lateral uterine segments. The ova when ingested may also develop into onchocerca that invade the intestinal wall but that do not develop into cysticercus cysts. D. latum can be eliminated as the proglottids are broader than long and possess a rosette-like coiled uterus, rather than branching extensions. The ova do not develop into cysticercoid onchospheres. D. caninum proglottids are longer than wide, and are distinctive for having double genital pores with vitalline ducts that serve to transport and excrete ova from each of the uteri. Question Difficulty: Level 1

A cyst was found in a human brain biopsy with characteristics of a cysticercus. These cysts may develop also in other body sites, particularly in the lungs. Cysticercosis in humans most commonly occurs as part of the life cycle of a tapeworm, the species of which is indicated by the proglottid shown in this image. From these observations, what is the name of the tapeworm of which cysticercosis is part of its life cycle? Taenia solium Diphyllobothrium latum Taenia saginata Dipylidium caninum

Moraxella catarrhalis The correct answer is Moraxella catarrhalis. The recovery of an oxidase-positive, gram negative diplococcus provides a presumptive identification of Neisseria sp. or Moraxella sp. The reactions seen in the Quad-FERM system [a lack of acid formation from glucose, maltose, lactose or sucrose (red color in the carbohydrate wells) and a positive DNA (yellow color in the well)] are characteristic of Moraxella catarrhalis which is known to be asaccharolytic. Neisseria gonorrhoeae is not a common pathogen of the lower respiratory tract and it would appear with a positive glucose in the Quad-FERM system. Neisseria meningitidis is a possible pathogen in the lower respiratory tract, but it would appear with a positive glucose and maltose in the Quad-FERM system. Neisseria lactamica is not a common pathogen of the lower respiratory tract, but is normal flora in the upper respiratory tract. It would also appear with a positive glucose and maltose in the Quad-FERM system. Question Difficulty: Level 4

A gram negative, oxidase-positive diplococcus was the predominant isolate from a sputum specimen of a patient with chronic obstructive pulmonary disease (COPD). Based on the reactions seen in the Quad-FERM system shown in the photograph, the most likely identification is: Moraxella catarrhalis Neisseria gonorrhoeae Neisseria meningitidis Neisseria lactamica

Listeria monocytogenes Listeria monocytogenes is the correct answer. There are many key characteristics of Listeria monocytogenes given in the question; gram positive bacilli, beta hemolytic, catalase positive, and tumbling motility in a hanging drop preparation. In addition, the picture shows a motility medium showing motility at the top of the tube, but not deeper, and overall looking like an umbrella. The umbrella shaped motility is another key characteristic of Listeria monocytogenes. Listeria monocytogenes has colony morphology almost identical to Streptococcus agalactiae. They are both beta hemolytic and can share many other reactions as well including CAMP test positive and hippurate hydrolysis positive. However, Streptococcus agalactiae is a gram positive cocci, catalase negative, and non-motile at room temperature, which differentiates the organism from Listeria monocytogenes. Erysipelothrix rhusiopathiae is also a gram positive bacilli. Typically colonies are non-hemolytic on sheep's blood agar. The catalase reaction is also negative. Erysipelothrix rhusiopathiae also shows a test tube brush-like appearance in a gelatin stab culture and is H2S positive. Escherichia coli is a gram negative bacillus, which eliminates it as the correct answer, since the question asks for a gram positive bacilli. E. coli can sometimes appear beta hemolytic on sheep's blood agar. Question Difficulty: Level 3

A gram positive bacillus grew as a diffusely beta-hemolytic colony from a newborn. It was catalase positive and had tumbling motility on a hanging drop preparation. The image shows how the organism grew in the motility medium. What is the most likely diagnosis? Listeria monocytogenes Streptococcus agalactiae Erysipelothrix rhusiopathiae Escherichia coli

Fonsecaea pedrosoi Fonsecaea pedrosoi is the correct response. This type of sporulation produces conidiophores that develop denticles, or small projections, that bear single conidia. Rarely do the conidiophores branch more than three times. Fonsecaea type of sporulation is the most common. Cladophialophora carrionii is incorrect because this fungus is recognized by its Cladosporium type sporulation, in which dark-staining elliptical conidia (lemon-shaped) are arranged in long branching chains, each separated by a "dysjunctor". Phialophora verrucosa is incorrect because this fungi is recognized by phialophora-type sporulation in which short urn-shaped conidiophores with narrow soda-bottle-shaped mouths release spherical conidia in small clusters. Resembles a vase of flowers. Exophiala jeanselmei is incorrect because this fungus is recognized by the exophiala type sporulation in which loose clusters of elliptical conidia are produced from the tips of long tapered conidiophores extending laterally from the hyphae. Most common isolate of Phaeohyphomyocsis infections. Question Difficulty: Level 9

A group of relatively slow growing fungi with distinctive dark brown to black colonies are the cause of infections of the skin known as Chromoblastomycosis. Clinically they appear as roughened multicolored verrucous vegetations, most commonly spreading over the dorsal surfaces of the lower legs and feet following penetrating injuries. A presumptive diagnosis of a fungus infection can be made on H & E - stained sections of a tissue biopsy by identifying oval/spherical bodies grouped in small clusters termed "sclerotic bodies" (more colloquial known as "copper pennies"), as illustrated in the top image. Dark gray-black pigmented mold colonies are grown in culture obtained from a biopsy specimen. The dark pigment is produced by deeply pigmented hyphae from the production of melanin, as illustrated in the bottom image. Note the branching conidiophores borne from the tips of hyphae giving rise to short chains of oval conidia. Select the presumptive species identification of this isolate. Cladophialophora carrionii Fonsecaea pedrosoi Phialophora verrucosa Exophiala jeanselmei

Nucleated red blood cells, spherocytes, polychromatophilic cells, Howell-Jolly bodies Notice the size variation (anisocytosis) of the erythrocytes on the infant's peripheral smear. There are normal-sized red blood cells, microcytes, spherocytes, macrocytes, and nucleated red blood cells present on this smear. Red cell variations are expected findings in healthy neonates, but the variations here are exaggerated. There are spherocytes, Howell-Jolly bodies, nucleated red blood cells, and polychromatophilic cells present in this image. A high (3-7%) reticulocyte count is not unusual during the first three or four days after birth, however, the bone marrow in this infant is proliferating vigorously in response to the ongoing hemolysis associated with this condition. As described above, alterations in size and shape of the RBCs is to be expected in this case and in neonates in general. However, schistocytes (remnants of RBCs) and target cells (cells with a pink area in the center of the pale area) are not seen in this image. Question Difficulty: Level 6

A known case of hemolytic disease of the newborn (HDN) is presented in the image on the right. Many different cellular morphologies are present. Apart from the obvious anisocytosis (microcytes and macrocytes), which additional red blood cell morphologies are worth reporting? Nucleated red blood cells, spherocytes, polychromatophilic cells, Howell-Jolly bodies Nucleated red blood cells, schistocytes, polychromatophilic cells, target cells Spherocytes, schistocytes, polychromatophilic cells, Howell-Jolly bodies Spherocytes, polychromatophilic cells, Howell-Jolly bodies, target cells

Providencia spp. Providencia spp. is the correct answer. The isolate is a unable to ferment lactose or sucrose on TSIA, is negative for H2S, is lysine decarboxylase negative, urease negative, citrate positive, phenylalanine deaminase positive, indole positive, and ornithine negative. Only Providentia and Proteus give a positive deamination reaction; however, Proteus are urease and H2S positive while Providentia are H2S and urease negative. Proteus mirabilis would be urease and H2S positive and indole negative. Escherichia coli would ferment lactose and sucrose in the TSIA, decarboxylate lysine and ornithine, and would be citrate and phenylalanine deaminase negative. Klebsiella pneumoniae would also ferment lactose and sucrose in the TSIA, would decarboxylate lysine, and be phenylalanine deaminase and indole negative. Question Difficulty: Level 7

A member of the Enterobacteriaceae is inoculated into various biochemical media which are shown in the image. Shown from left to right are triple sugar iron agar (TSIA), lysine iron agar, urea agar, citrate agar, phenylalanine deaminase agar, and motility indole ornithine agar. This organism is most likely: Proteus mirabilis Providencia spp. Escherichia coli Klebsiella pneumoniae

Pseudomonas putida The "fluorescing" pseudomonads include Pseudomonas aeruginosa, Pseudomonas fluorescens, and Pseudomonas putida. All other pseudomonas and pseudomonas-like bacterial species (including all members of the Burkholderia and Comamonas genera which were formerly in the genus Pseudomonas) do not produce fluorescence when growing on Pseudo F agar. Pseudomonas putida and Pseudomonas fluorescens both produce fluorescence on Pseudo F agar, neither produces pyocyanin nor grows at 42° C. Pseudomonas putida does not hydrolyze gelatin whereas Pseudomonas fluorescens does. Pseudomonas stutzeri, Pseudomonas alcaligenes, and Burholderia cepacia do not produce pyocyanin or fluorescein and will not fluoresce on Pseudo F agar slant. Question Difficulty: Level 7

A patient had a transfusion reaction to red blood cells and the remains from the unit of blood were sent to the microbiology laboratory for culture. The organism that grew was a gram-negative bacilli that was catalase and oxidase positive and was negative for gelatin hydrolysis. The organism was inoculated on a Pseudo F agar slant and incubated for 24 hours. Fluorescence was observed when using a UV light as seen in the image. This organism is most likely: Pseudomonas putida Pseudomonas stutzeri Burkholderia cepacia Pseudomonas alcaligenes

May-Hegglin anomaly inclusion The black arrow points to a May-Hegglin anomaly inclusion. This inclusion resembles a Döhle body. However, toxic changes are not present as they would be if this were a Döhle body. The giant platelets that are observed in the field also help to identify this as May-Hegglin anomaly, the condition that is producing these inclusions. Auer rods are fused primary granules and can be seen in leukemic cells (primarily myeloblasts and promyelocytes) in acute myelocytic leukemia. A Barr body is a nuclear appendage representing the inactivated X chromosome in females. A Döhle body is a blue inclusion (ribosome) in neutrophils associated with toxic changes (e.g., in bacterial infection). Question Difficulty: Level 6

A patient has a WBC count of 4.0 x 109/L. Giant platelets, such as the one indicated by the red arrow in the image, are observed on the Wright stained peripheral smear. Blue-staining inclusions are also observed in several of the neutrophils. Considering the morphologies noted by the black and red arrows, what is the identity of this patient's blue-staining WBC inclusions? Auer rod Barr body Döhle body May-Hegglin anomaly inclusion

Iron deficiency anemia The correct answer choice here is iron deficiency anemia. The patient's clinical symptoms and laboratory picture are most consistent with iron deficiency anemia. The cells appear hypochromic with a marked poikilocytosis and anisocytosis. Sickle cell, megaloblastic, and aplastic anemias do not have the clinical symptoms or peripheral smear characteristics that this case displays. Sickle cell anemia can be easily recognized by the distinct sickle shaped cells that form when oxygenated blood releases oxygen particles to parts of the body. The hematology technologist should note the sickled cells and notify the attending physician so that a sickle cell screen can be performed to confirm the patient has sickle cell anemia. Megaloblastic anemia is a macrocytic (oval macrocytes) anemia and would present with characteristic hypersegmented neutrophils. Megaloblastic anemia's two most common causes are vitamin B12 deficiency and folate deficiency. Aplastic anemia can present on a manual differential similar to iron deficiency anemia. Patient's with aplastic anemia usually have some type of infection, are on medication that can cause a decrease in RBCs, or have been exposed to toxic chemicals. Question Difficulty: Level 6

A patient is admitted to the emergency room with severe lethargy, glossitis, and muscle dysfunction. After the physician orders a complete blood count with differential, the hematology technologist observes cells matching the image to the right. Which condition is most consistent with the clinical and laboratory findings? Sickle cell anemia Megaloblastic anemia Iron deficiency anemia Aplastic anemia

Streptococcus pyogenes Streptococcus pyogenes is the causative agent of cellulitis in this patient. S. pyogenes grows as small catalase negative colonies with a small zone of beta hemolysis on 5% sheep blood agar. The Gram stain shows gram positive cocci in chains. If left untreated the patient may progress into streptococcal toxic shock syndrome. Staphylococcus aureus infections may also produce cellulitis in people that can be difficult to treat and sometimes lead to a toxic shock syndrome. However, in the case of this patient, S. aureus is not the cause of infection. S. aureus grow as larger catalase positive cream colored colonies on 5% sheep blood agar with a wide zone of beta hemolysis, sometimes seen as a double zone. The Gram stain for S. aureus show gram positive cocci in clusters. Although Pseudomonas aeruginosa may be seen in soft tissue infections, it is most often associated with cystic fibrosis patients and situations where biofilms are generated. P. aruginosa grows as large oxidase positive beta hemolytic colonies with a green to silver sheen on 5% sheep blood agar. They also grow as non-lactose fermenting colonies on MacConkey agar. The Gram stain for P. aruginosa shows gram negative bacilli. Enterococcus faealis appear morphologically similar to S. pyogenes by Gram stain; however, E. faecalis grow as small catalase negative gray colonies on 5% sheep blood agar and do not show any hemolysis. E. faecalis may be seen in some soft tissue infections, but does not typically cause cellulitis. Question Difficulty: Level 8

A patient presents with cellulitis and culture growth small beta hemoytic colonies on 5% Sheep blood agar. The gram stain of the organism is included. What is the most ikely cause of the infection. Streptococcus pyogenes Staphylococcus aureus Pseudomonas aeruginosa Enterococcus faecalis

Lymphocytes and Blasts In this cerebrospinal fluid cytospin, the predominant cell type appears as large cells with irregularly shaped nuclei, prominent nucleoli, and scant cytoplasm. These cells are L2 Lymphoblasts and would be reported as blasts. Examples are indicated by the red arrows. There are also a few normal lymphocytes in this field as well. Examples are indicated by the blue arrows. Question Difficulty: Level 9

A patient suffering from typical leukemic symptoms presents in the emergency room. Physicians order a spinal tap after noticing possible central nervous system involvement. What are the cells seen in the spinal fluid cytospin preparation? Reactive mesothelial cells Lymphocytes and Blasts Monocytes Reactive Lymphocytes

Streptococcus pneumoniae Assuming an alpha hemolytic reaction (not well seen in the image), viridans streptococcus and S. pneumoniae are the two possible responses. However, these colonies are far too mucoid for viridans streptococci; therefore, S. pneumoniae is the most likely choice. Also, the colonies are much too large and the hemolytic reaction is wrong for S. pyogenes or S. agalactiae. Question Difficulty: Level 3

A patient was admitted to the hospital recently with an obvious infection. A sputum specimen was submitted and the microbiologist inoculated it to sheep blood agar. Based on the colony morphology and the alpha hemolysis seen in the image to the right, the most likely identification is: Streptococcus pneumoniae viridans streptococcus Streptococcus pyogenes Streptococcus agalactiae

Rouleaux The red blood cells present in this image have "stacked coins" formation. This is known as rouleaux formation, which is highly associated with conditions where increased serum proteins, particularly fibrinogen and globulins, are present. This stacking is also the mechanism for increased sedimentation rates, as associated with multiple myeloma and other inflammatory conditions. Plasma cell disorders such as multiple myeloma are characterized by a clonal population of plasma cells that produce a monoclonal protein (M protein, or paraprotein), causing the red blood cells to stick together and form rouleaux. Agglutination is the clumping of erythrocytes due to interactions of membrane antigens and antibodies (immunoglobulins). Polychromasia refers to the presence of varying RBC color. Polychromasia usually indicates the presence of reticulocytes. Hypochromia refers to RBC's with a larger than normal central pallor. Normal RBC's have one-third central pallor, whereas hypochromic cells have greater than one-third central pallor. This is usually indicated by a low MCHC on the CBC. Question Difficulty: Level 1

A patient with multiple myeloma is admitted to the hospital due to a flare up of symptoms. Her physician orders a complete blood count with differential. The peripheral blood smear is shown. Which morphology is consistent with the findings in this case? Rouleaux Agglutination Polychromasia Hypochromia

Plasma cells The predominant cells in this image are plasma cells. This patient may have been suffering from a plasma cell malignancy in the abdominal cavity or been under stress conditions, hence the presence of numerous plasma cells in the peritoneal fluid. All of the cells have a characteristic perinuclear hof seen in plasma cells, but not seen in monocytes, atypical lymphocytes, or blasts. Question Difficulty: Level 6

A patient with suspected intraabdominal malignancy had a paracentesis performed. The fluid was then sent to the laboratory for examination and fluid differential. Which cells predominate in this cytospin field from the patient's sample? Monocytes Atypical lymphs Blasts Plasma cells

Neutrophils and bacteria In this image, there are intracellular bacteria inside of the neutrophils, a sign of bacterial infection; therefore, both of these observations should be reported. In addition, extracellular bacteria is also noted in the field. This finding should be included as well. Lymphocytes have round nuclei and may be associated with viral infection. Eosinophils have large orange granules in the cytoplasm. Mesothelial cells, cells that line the peritoneal cavity, are large and may be multinucleated. Question Difficulty: Level 6

A physician obtains a peritoneal fluid sample by lavage on a patient who complained of fever and abdominal pain following an automobile accident. The fluid is analyzed in the laboratory. How should the sample shown in the image to the right be reported? Lymphocytes Eosinophils and parasites Mesothelial cells Neutrophils and bacteria

Cells in the gated population are co-expressing CD5 and CD20. The scatterplot represents co-expression of CD5 and CD20. Quadrant 2 (Q2) of the scatterplot contains CD5/CD20 + cells. Normally CD5 positive cells represent T lymphocytes, while CD20 positive cells represent B lymphocytes. In this case, a single cell population is expressing both markers. If cells were predominantly expressing CD5 but not CD20, the cells would be in quadrant 1 (Q1). If cells were predominantly expressing CD20, but not CD5, the cells would be in quadrant 4 (Q4). If cells were not expressing neither CD5 nor CD20, the cells would be in quadrant 3 (Q3). Question Difficulty: Level 4

A population of small lymphocytes is gated for further evaluation in the flow cytometry laboratory. The scatterplot for one of the evaluations is shown on the right. How would you interpret this scatterplot? Cells in the gated population are predominantly expressing CD5, but not expressing CD20. Cells in the gated population are predominantly expressing CD20, but not CD5. Cells in the gated population are co-expressing CD5 and CD20. Cells in the gated population are expressing neither CD5 nor CD20.

The pathogenicity of Staphylococcus aureus, as well as the frequency with which this organism produces infections, can be attributed to all of the following EXCEPT: Exfoliative toxin and enterotoxins A porous cell wall Natural colonization/reservoir for infection Hyaluronidase

A porous cell wall Staphylococcus aureus colonizes approximately 25 - 30 % of the general population, providing significant reservoirs of organism for transmission. In addition, it produces a number of different enzymes and toxins, including (but not limited to) exfoliative toxin, enterotoxins, hyaluronidase and lipase, and beta lactamases. The cell wall of S. aureus is not porous. Structural components of its cell wall function as a protective barrier, aid in adherence to mucous membranes, and allow the organism to resist phagocytosis. Question Difficulty: Level 8

Which of the following best describes a hemoglobinopathy? Any problem involving hemoglobin destruction. Any problem associated with hemoglobin production. A deletion of the loci of one or more hemoglobin chains. A substitution of an amino acid in the hemoglobin chain.

A substitution of an amino acid in the hemoglobin chain. A hemoglobinopathy is a substitution of an amino acid in the hemoglobin chain. When an amino acid substitution occurs, a new protein is formed. Hemoglobin destruction or problems with hemoglobin production are not exclusive to hemoglobinopathies. Other anemias that are not considered hemoglobinopathies may also involve increased hemoglobin destruction or problems with hemoglobin production. However, other anemias demonstrating hemoglobin production problems do not form an abnormal hemoglobin protein. Deletion of a hemoglobin chain loci results in decreased production of that chain (thalassemia), and not production of a different hemoglobin protein. Question Difficulty: Level 7

Anti-Jka and anti-E After evaluating the panel results, the antibodies that are most likely present and causing the agglutination pattern observed are Anti-E and Anti-Jka. There is a variation in strength seen (reaction strength is 2+ to 4+) suggesting multiple antibodies are present. When looking at anti-Jkb, Anti-k, and Anti-Leb,each are either ruled out and/or do not match the agglutination pattern present. Question Difficulty: Level 7

A technologist performing an antibody identification in the blood bank has recorded the following results found in the worksheet below. Which antibody(ies) are MOST LIKELY the cause of the agglutination reactions? Only anti-Jkb Anti-k and anti-Jkb Only Anti-Leb Anti-Jka and anti-E

G6PD deficiency Note particularly the spherocytes in the upper image to the right. Some resemble a half-blister with the other half of the cell containing solidly-staining hemoglobin. These are called eccentrocytes. When present, along with a suspicious patient history, they should trigger an evaluation for G6PD deficiency. Upper image: The blue arrows in the upper photomicrograph are directed toward solid-staining spherocytes in which the cell membrane is beaded by inclusions wrapped within the cell membrane, suggesting the remains of denatured hemoglobin. Included on the smear is a target cell, several acanthocytes, a smudge cell, and a few schistocytes. Lower image: This is a supravital staining of the affected red blood cells, confirming the presence of Heinz bodies, a key diagnostic feature of this condition. Pyruvate kinase deficiency is associated with a normocytic, normochromic anemia with poikilocytosis and anisocytosis, but Heinz bodies are not found in this condition. Iron deficiency anemia is assoiciated with a microcytic, hypochromic anemia and is not associated with the presence of Heinz bodies. Finally, megaloblastic anemia is considered a macrocytic, normochromic anemia associated with abnormal red blood cell development. This condition is also not associated with the presence of Heinz body inclusions. Question Difficulty: Level 4

A ten-year-old boy came to a physician's attention because of recent jaundice and icteric sclera after taking the medication Primaquine before a trip to Africa. The immediate laboratory work revealed: Hct 24% (normal 36%-47%), MCV 79.5 fL (normal 78-95fL), RDW 13% (normal 11.5-15.0%). His blood smear findings are reflected in the images to the right. The upper image is a Wright-Giemsa stained smear while the lower is a supravital-stained smear. Which condition should be considered for this patient when analyzing his symptoms, history, and laboratory results? G6PD deficiency Pyruvate kinase deficiency Iron deficiency anemia Megaloblastic anemia

Enterobacteriaceae The correct answer is Enterobacteriaceae. The key biochemical reactions by which the family Enterobacteriaceae can be identified include fermentation of carbohydrates, reduction of nitrates to nitrites and the absence of cytochrome oxidase activity. Some or all of the members of the other families of bacteria listed produce cytochrome oxidase. A positive spot oxidase test, as shown in this photograph, is a useful in separating these families of bacteria from members of the Enterobacteriaceae family. Question Difficulty: Level 5

A unidentified colony was inoculated to the surface of a filter paper strip impregnated with cytochrome oxidase reagent (dimethyl-p-phenylenediamine dihydrochloride) as shown in the picture on the right. The family of bacteria ruled out by the reaction seen is: Pasteurellae Neisseriaceae Enterobacteriaceae Pseudomonadaceae

Count the number of cells that resemble the cells in this image (per 100 WBCs) and compute for the corrected WBC count using the formula, Total WBCs x100 / 100+ number of NRBCs The nucleated cells shown in the image are nucleated red blood cells (NRBCs). These cells are normally present in the blood of newborn infants. If the hematology analyzer that is used includes all NRBCs in its automated WBC count, a manual differential must be performed. On the stained smear, if more than 5 NRBCs are seen per 100 WBCs, the total white blood cell count must be corrected by using the following formula: Corrected White Blood Cell Count = WBC Count x 100 / 100 + number of NRBCs* * Number of NRBCs = number of nucleated red blood cells that are counted per 100 WBCs Corrected White Blood Cell Count = 28.2 x 109/L x 100/ 100 + 6 = 26.6 x 109/L The white blood cell count must not be reported to the physician until this correction is made. Question Difficulty: Level 2

A white blood cell (WBC) count is performed on a blood specimen from a newborn using a hematology analyzer that does not have the capability to detect and quantify nucleated red blood cells (NRBCs). The WBC count that is reported by the analyzer is 28.2 x 109/L and it is flagged for a manual differential. Upon review of the blood film, more than 6 nucleated cells that resemble the cells shown in the image were identified in the 100 WBC differential. What action should be taken? Report the automated white blood cell count and the manual differential results immediately to the physician. Count the number of cells that resemble the cells in this image (per 100 WBCs) and subtract that number from the WBC count that was reported by the analyzer. Count the number of cells that resemble the cells in this image (per 100 WBCs) and compute for the corrected WBC count using the formula, Total WBCs x100 / 100+ number of NRBCs Add the NRBCs to the WBC count.

Disseminated intravascular coagulation (DIC) As can be seen from this patient's laboratory test results, her D-dimer is elevated, her PT and aPTT are prolonged, her fibrinogen and platelet count are dramatically decreased. This is a classic profile for DIC. Thrombocytopenia and the presence of schistocytes on the peripheral blood smear are also associated with TTP and HUS, but the abnormal D-dimer and coagulation tests point to DIC. Glanzmann thrombasthenia (GT) patients have a defective glycoprotein IIb/IIIa on their platelets with leads to ineffective platelet aggregation. GT patients usually have a normal platelet count but an abnormal bleeding time. Question Difficulty: Level 3

A woman in labor is bleeding, has a very high fever, and is in danger of losing the fetus. Laboratory results include a platelet count of 15 x 109/L (normal platelet count = 150 - 450 x 109/L), prolonged PT and aPTT, decreased fibrinogen, and increased D-dimer. Her automated blood count flagged for blood smear review, and the cells indicated by the arrows were seen on her peripheral smear along with a decrease in the number of platelets present. What condition is suggested by these results? Thrombotic thrombocytopenic purpura (TTP) Hemolytic uremic syndrome (HUS) Disseminated intravascular coagulation (DIC) Glanzmann thrombasthenia (GT)

Which of the following factors do not affect hybridization? G:C content A:T content pH Temperature

A:T content A:T content does not affect hybridization. Hybridization is the pairing or annealing of two strands of DNA. Several environmental factors can influence this process: Temperature: If the temperature is too high, the strands melt. If it is too low, they might be forced together. The pH: A pH that is too alkaline will cause the strands to separate; too acidic and they are forced together. The guanine to cytosine ratio (G:C ratio): Since this bond is stronger than the other nucleotide bonds, if the G:C ratio in the desired target strand is high, the separation process may take longer. Question Difficulty: Level 7

The direct antiglobulin test (DAT) is most unreliable when diagnosing hemolytic disease of the fetus and newborn due to which blood group system? ABO Duffy Rh Kidd

ABO The correct answer is ABO. In ABO HDFN, the DAT result is neither strongly nor consistently positive. The DAT is usually reliable for antibodies in the Duffy, Rh and Kidd antibody systems. Question Difficulty: Level 7

What is the cause of iron overload in hereditary hemochromatosis? Absorption of excessive amounts of iron in the small intestine Ingestion of excessive amounts of iron from diet or supplements Inability of the body to excrete normal amounts of dietary iron Failure of developing red blood cells to incorporate iron into protoporphyrin IX

Absorption of excessive amounts of iron in the small intestine Hereditary hemochromatosis is a genetic disorder typically involving a deficiency of hepcidin due to a mutation in the hepcidin gene or genes whose products regulate the expression of hepcidin. These mutations cause increased iron absorption in the small intestine, leading to iron overload. Ingestion of excessive amounts of dietary iron results in secondary hemochromatosis. Iron is recycled when cells die; the body does not have a mechanism for iron excretion. Failure of developing red blood cells to incorporate iron into protoporphyrin IX results in a sideroblastic anemia. Question Difficulty: Level 7

Which group of conditions increases the risk of HbS polymerization? Acid pH, dehydration, decreased level of 2,3-DPG Alkaline pH, dehydration, increased level of 2,3-DPG Acid pH, dehydration, increased level of 2,3-DPG Alkaline pH, dehydration, decreased level of 2,3-DPG

Acid pH, dehydration, increased level of 2,3-DPG The risk of HbS polymerization is enhanced by a low (acid) pH, a state of dehydration, and increased levels of 2,3-DPG. Increased temperature (above 37°C) also adds to the risk. Question Difficulty: Level 7

Gas-liquid chromatography is useful in the identification of anaerobes in addition to Gram-stain morphology. Which anaerobe produces succinic acid in abundance? Fusobacterium nucleatum Lactobacillus sp. Actinomyces israelii Clostridium difficile

Actinomyces israelii Many strains of Actinomyces species, including Actinomyces israelii, have the unique feature of producing major quantities of succinic acid, in comparison to lesser amounts of other nonvolatile acids. Fusobacterium nucleatum produces major amounts of butyric acid and does not produce succinic acid. Lactobacilli sp. produces lactic acid as its sole product. Clostridium difficile produces large quantities of several volatile acids, including butyric and isocaproic, which results in its characteristic barn yard smell when recovered in culture. Question Difficulty: Level 8

Fifty percent blasts are found on a peripheral blood smear. The cells are large (3-5x the size of a lymphocyte) with a nucleus that contains homogeneous fine chromatin and two to three nucleoli. There is moderate blue-grey cytoplasm with Auer rods. What leukemia is most likely? Acute myelogenous leukemia (AML) Hairy cell leukemia (HCL) Acute lymphoblastic leukemia (ALL) Chronic lymphocytic leukemia (CLL)

Acute myelogenous leukemia (AML) Acute myelogenous leukemias (AML) cause the bone marrow to produce (and eventually show in the peripheral blood) ≥20% blasts of the nonerythroid nucleated cells. Auer rods are only present in myelogenous cells, and can be seen in about half of the AML cases. HCL, ALL, and CLL are all leukemias affecting the lymphocytic cell line and the presence of Auer rods in the blasts would not be seen. Question Difficulty: Level 8

Which adipokine is decreased in obesity, is anti-inflammatory, and increases insulin sensitivity? Leptin Resistin TNF-a Adiponectin

Adiponectin Adiponectin is a protective cytokine synthesized and secreted almost exclusively by the adipocytes. This cytokine is anti-inflammatory and increases insulin sensitivity. Levels of adiponectin are decreased in weight gain, obesity, and in those who are insulin resistant. Leptin is synthesized and released from adipose cells in response to adipose tissue changes. It reduces intracellular lipid levels in many types of body cells and thus improves insulin sensitivity, but is usually increased in obesity NOT decreased. It is an appetite suppressant and inhibitor of fatty liver formation. Resistin is another inflammatory cytokine that is increased in obesity. It increases insulin resistance and enhances adhesion molecules present on endothelial cells. It is synthesized and secreted by macrophages and adipocytes. Adipocyte-secreted TNF-α stimulates adipocytes to increase their release of non-esterified fatty acids and decrease adiponectin synthesis. TNF-α also inhibits insulin activity, leading to insulin resistance. Adipocyte TNF-α secretion is increased in obesity causing an increased insulin resistance in obesity. Question Difficulty: Level 7

Sickle Cell Anemia The correct answer here is sickle cell anemia. This cell, which is sickle-shaped, is indicative of the presence of hemoglobin S. Polychromasia is also commonly observed in sickle cell anemia. Sickling occurs after oxygen is released from the hemoglobin. With beta thalassemia, the patient can feel fatigued, have shortness of breath, but normally does not have crippling pain. Upon examination by the hematologist an array of RBC morphologies can be present such as hypochromasia, microcytosis, basophilic stippling, but sickle cells are only present in patients with sickle cell anemia/trait. Myocardial infarction is not common in children. A patient is most rapidly diagnosed with a myocardial infarction by running chemistry testing such at with a troponin. Hemoglobin C disease does sometimes give patients, especially children, abdominal and joint pain. Unlike sickle cell anemia these patients will not have crippling pains. Upon blood smear analysis the technologist should find characteristic hemoglobin C crystals. Question Difficulty: Level 3

After experiencing crippling pain in her chest, Elizabeth's mother rushes her to the Emergency Room. After a complete blood count and differential are ordered, the hematology technologist views many peripheral cells similar in appearance to those found in the image below. Which condition is most likely present? Beta Thalassemia Myocardial Infarction Sickle Cell Anemia Hemoglobin C Disease

Mesothelial cells, neutrophils and red blood cells The major cells present are mesothelial cells in a clump, which is consistent with a patient with pneumonia. There are also segmented neutrophils and red blood cells present as well in the background. Macrophages are monocytes that have phagocytized materials inside the cells. Tumor cells or neoplastic cells can be found in loosely joined clusters. Cytoplasmic vacuoles are frequently present. The nuclei tend to be larger with irregular nuclei. Plasma cells have a round, eccentrically placed nucleus with deeply basophilic cytoplasm with a lighter staining paranuclear area. Plasma cells are slightly smaller than mesothelial cells. Question Difficulty: Level 9

After reviewing this cytospin from a pleural fluid, identify the cells that would be the appropriate to report? Macrophages, neutrophils and red blood cells Mesothelial cells, neutrophils and red blood cells Tumor cells, neutrophils and red blood cells Plasma cells, neutrophils and red blood cells.

Bronchial lining cells The cells shown in this bronchoalveolar lavage (BAL) are bronchial lining cells. The cells have a rounded nucleus at one end of the cell with a column of cytoplasm. A few have intact cilia while others do not. The presence of cilia definitively identifies this cell type. The presence of these cells indicate that the specimen was obtained from the upper respiratory tract as opposed to deeper within the lung. Lymphocytes have a rounded nucleus. The cytoplasm typically surrounds the nucleus. They may be present in BAL specimens. Mesothelial cells are not seen in BAL specimens. They are lining cells that may be found in other serous body fluids Macrophages have differentiated from monocytes and can be found in BAL and other body fluids. They are large and have a round or oval nucleus. They are phagocytic cells, so the cytoplasm is often filled with debris and / or vacuoles. Question Difficulty: Level 4

After suspecting that his patient may have lung disease, the physician sends a bronchoalveolar lavage (BAL) to the laboratory for examination. What is the cell type noted by the arrows in this cytospin sample? Lymphocytes Mesothelial cells Macrophages Bronchial lining cells

False-positive tests for protein on a urine reagent strip may be caused by: Blood presence in the specimen High amounts of bilirubin Alkaline medication All of the above

All of the above Blood presence in the specimen, high amounts of bilirubin, and the presence of alkaline medication are all factors which can cause false positives on the protein pad of a urine reagent strip. The reagent test strip reaction is based on the "protein error of indicators" principle which means that the point of color change of pH indicators is different when protein is present versus when protein is not present. This phenomenon occurs because proteins act as hydrogen ion acceptors at a constant pH. Albumin is the main protein which is measured by the urine protein pad on the reagent strip because it contains more amino groups to accept hydrogen ions than other groups. Albumin is also the protein which is found in the highest concentrations in the body. When blood is present in the urine specimen, cells tend to lyse and their contents contain albumin and other proteins which may interfere with the chemical test strip reaction. High amounts of bilirubin can obscure color reactions. Medication may alter the pH of the urine to become alkaline which in turn will overcome the acid buffer on the reagent pad and change the color to show a false positive result. Question Difficulty: Level 7

Phialophora verrucosa Phialophora verrucosa is a causative agent of Chromoblastomycosis (Chromomycosis) a chronic infection of skin and subcutaneous tissue that develops over months or years. It is considered a pathogenic species. Alternaria species, Chrysosporium species and Mucor species are all considered opportunists that are present in the environment and are not normally a concern in regards to human disease. They may cause infections in compromised individuals under the right conditions. Question Difficulty: Level 8

All of the following are considered opportunistic pathogens EXCEPT: Alternaria species Chrysosporium species Phialophora verrucosa Mucor species

Hemoglobin D (HbD) is elevated in all of the following EXCEPT? Hemoglobin D disease Hemoglobin SD disease Hb D/beta-thalassemia Alpha thalassemia

Alpha thalassemia HbD is not present in alpha thalassemia. HbD is an inherited autosomal recessive variation of HbA that occurs in the β-globin protein chain of HbA. The formation of HbD occurs by substitution of glutamic acid for glutamine at codon 121 of the β-chain. HbD disease, also known as HbDD, occurs when two copies of the Hb D variant gene are inherited. It is also possible to inherit a condition known as Hb D/beta-thalassemia (Hb D/β-thal). Although rare, HbSD does exist. Question Difficulty: Level 8

Sickle cell disease Hemoglobin electrophoresis is necessary to confirm this diagnosis. However, the presence of numerous target cells and sickle cells suggests HbSS or sickle cell disease. In autoimmune hemolytic anemia, sickle cells and target cells are not present. Possible findings would be spherocytes and schistocytes. In beta thalassemia, target cells would be seen, but not sickle cells. Also, the RBCs would be microcytic and hypchromic. In Hemoglobin C disease, target cells could be present, but Hb C crystals would be seen rather than sickle cells. Question Difficulty: Level 4

An 8-year-old girl's peripheral blood smear is shown in the image on the right. Based on the peripheral blood image, what is a likely diagnosis? Autoimmune hemolytic anemia Beta thalassemia Sickle cell disease Hemoglobin C disease

Propionibacterium acnes Microscopic observation of the cell morphology and arrangement as seen in Gram stained preparations is often helpful in making a preliminary identification of anaerobes. In this exercise, the Gram stained preparation reveals short, slender gram positive bacilli that are haphazardly arranged in a coryneform formation. From the bacterial species listed, this morphology and the growth of an anaerobic organism is most consistent with Propionibacterium acnes. Corynebacterium jeikeium will also appear as slender gram positive bacilli in coryneform formation; however, C. jeikeium is an aerobic bacterium that will usually indicate a positive blood culture within 48 hours. Fusobacterium nucleatum are anaerobic gram negative bacilli that are slender with pointed ends. Clostridium perfringens is an anaerobic gram positive bacillus; however, they appear as rectangular or "box car" in shape when Gram stained. They align as single cells or in a chain, as opposed to the coryneform shape seen in the Gram stain. Question Difficulty: Level 8

An anaerobe was recovered from a blood culture after 92 hours incubation. A gram stain of the isolate is illustrated in the photomicrograph. The most likely identification is: Propionibacterium acnes Corynebacterium jeikeium Fusobacterium nucleatum Clostridium perfringens

Anti-Fya, -C The correct answer is anti-Fya and anti-C. This is a fairly basic panel, but it involves further thought. First, it asks you to determine which antibodies are not ruled out. Upon completing the rule-outs on screen cell #3, one must then evaluate those remaining antibodies that have not been ruled out for clinical significance. Eliminate choice A immediately, because D is ruled out based on cell #3 at the clinically significant phase of 37°C. Next, it asks you to assess which of the antibodies that have not been ruled out are clinically significant. Of the remaining choices (B, C, and D), you can immediately rule out choices B and C, because both choices contain antibodies that are not clinically significant (anti-Lub, -Lea). Two antibodies that you are unable to rule out at the clinically significant phase of 37°C are contained in the only remaining answer choice, which is choice D. Anti-Fya and anti-C also happen to be clinically significant, because they are reactive at 37°C and can impact the patient in vivo. Question Difficulty: Level 9

Anti-Fya, -D Anti-Lub, -Lea, -Fya, -C Anti-Lea, -Fya, -C Anti-Fya, -C

Which antibody is associated with Mycoplasma pneumoniae infection and cold hemagglutinin disease? Anti-P Anti-I Anti-M Anti-i

Anti-I M. pneumoniae carries an antigen that resembles I antigen. Thus, when the body develops an immune response against this antigen, the antibodies may cross react with I antigen on red blood cells. Anti-I is also associated with cold hemagglutinin disease. Anti-P may be associated with paroxysmal cold hemoglobinuria. Anti-M can occur naturally and often reacts at room temperature but is not associated with a specific disease. Anti-i is associated with infectious mononucleosis, lymphoproliferative disease, and sometimes with cold hemagglutinin disease. Question Difficulty: Level 9

Pelger-Huet anomaly The correct answer for this question is "Pelger-Huet anomaly." The WBCs seen in the image are neutrophils, each with a bi-lobed nucleus. Hyposegmentation of the nucleus in granulocytes is associated with "Pelger-Huet anomaly." True Pelger-Huet anomaly is an inherited condition that results in 70% to 90% of neutrophils showing hyposegmentation (single lobed or bi-lobed). These neutrophils are functionally normal, and most findings are incidental. Infections can sometimes cause a "shift to the left" which implies a release of younger granulocytes from the bone marrow to peripheral blood. The cells in this image are not bands, due to the small filament connecting each lobe of the nucleus. It is important not to confuse bands with Pelger-Huet cells. Folic acid deficiency often results in hypersegmented neutrophils. Hypersegmentation is when the nucleus of a neutrophil has more than five lobes. Leukemoid reactions are characterized by a significant leukocytosis and neutrophilia with a shift to the left. Question Difficulty: Level 3

Approximately 80 - 90% of the neutrophils on the peripheral blood smear of a young man are similar to those in the image. This peripheral smear most likely represents which condition? Infection, with a shift to the left Folic acid deficiency Pelger-Huet anomaly Leukemoid reaction

All of the following fungi are appropriately listed with their respective morphology, EXCEPT: Syncephalastrum sp. produce merosporangia Fusarium sp. produce macroconidia Coccidioides immitis produces arthroconidia Aspergillus sp. produce ascospores

Aspergillus sp. produce ascospores The correct answer is Aspergillus sp. produce ascospores. Aspergillus sp. produce chains of conidia on the end of phialides. Ascospores, sexual spores, are produced by Pseudallescheria boydii. Syncephalastrum sp. produce merosporangia which appear as "daisy petals" around a columella. Fusarium sp. produce macroconidia that are canoe-shaped and microconidia that are elliptical shaped arranged in a "Chinese-letter" pattern. Coccidioides immitis produces arthroconidia which are hyphae that have vegetative cells or dysjunctor cells between each arthroconidia which gives an alternating staining pattern that is typical of arthroconidia and helps to distinguish them from septate hyphae. Question Difficulty: Level 8

A standard 4.5-mL blue-top tube filled with 3.0 mL of blood was submitted to the laboratory for PT and APTT tests. The sample is from a patient undergoing surgery the following morning for a tonsillectomy. Which of the following is the necessary course of action by the technologist? A. Run both tests in duplicate and report the average result B. Reject the sample and request a new sample C. Report the PT result D. Report the APTT result

B A 4.5-mL blue-top tube contains 4.5 mL blood + 0.5 mL sodium citrate. The tube should be 90% full. A tube with 3.0 mL blood should be rejected as quantity not sufficient (QNS). QNS samples alter the necessary blood to an anticoagulant ratio of 9:1. The excess anticoagulant in a QNS sample binds to the reagent calcium, thereby resulting in prolongation of the PT and APTT. Harr, Robert R. Medical Laboratory Science Review (Page 46). F.A. Davis Company. Kindle Edition.

Material from a fungus-ball infection produced colonies with a green surface on Sabouraud agar in 5 days at 30°C. Microscopic examination showed club-shaped vesicles with sporulation only from the top half of the vesicle. This hyaline mold is most probably which Aspergillus spp.? A. A. niger B. A. fumigatus C. A. flavus . A. terreus

B A. fumigatus is the most common cause of aspergillosis. It is characterized by sporulation only from the upper half or two-thirds of the vesicle. Colonies of A. niger are white with black pepper growth and produce phialides over the entire vesicle, forming the classic "radiate" head. A. flavus colonies are yellow to yellow-green and produce phialides that cover the entire vesicle and point out in all directions. A. terreus produces brown colonies and phialides that also cover the entire vesicle. Harr, Robert R. Medical Laboratory Science Review (Page 452). F.A. Davis Company. Kindle Edition.

SITUATION: A GC-MS analysis using nitrogen as the carrier gas shows an extensively noisy baseline. A sample of the solvent used for the extraction procedure, ethyl acetate, was injected and showed the same noise. Results of an Autotune test showed the appearance of a base peak at 16 with two smaller peaks at 17 and 18. These results indicate: A. The solvent is contaminated B. The carrier gas is contaminated C. There is electrical noise in the detector D. The ion source is dirty

B All of these situations are sources of baseline noise in GC-MS. However, the peak at 16 indicates the presence of oxygen in the carrier gas. Oxygen in the atmosphere also contains small quantities of two isotopes with molecular weights of 17 and 18 owing to one and two extra neutrons, respectively. Harr, Robert R. Medical Laboratory Science Review (Page 187). F.A. Davis Company. Kindle Edition.

A small, gram-negative coccobacillus recovered from the CSF of a 2-year-old child gave the following results: Indole = + Glucose = + (acid) X requirement = + V requirement = + Urease = + Lactose = Neg Sucrose = Neg Hemolysis = Neg Which is the most likely identification? A. Haemophilus parainfluenzae B. Haemophilus influenzae C. Haemophilus ducreyi D. Haemophilus aphrophilus

B Although several biotypes of H. parainfluenzae produce indole and urease, H. parainfluenzae does not require X factor for growth. H. ducreyi requires X factor but not V factor. H. aphrophilus does not require either X factor or V factor for growth. Harr, Robert R. Medical Laboratory Science Review (Page 413). F.A. Davis Company. Kindle Edition.

SITUATION: A lipemic specimen collected from an adult after a 12-hour fast was assayed for total cholesterol, triglycerides, and HDL cholesterol using a direct HDL method. Following are the results: Total cholesterol = 220 mg/dL HDL cholesterol = 40 mg/dL Triglyceride = 420 mg/dL The physician requests an LDL cholesterol assay after receiving the results. How should the LDL cholesterol be determined? A. Dilute the specimen 1:10 and repeat all tests; calculate LDL cholesterol using the Friedewald equation B. Perform a direct LDL cholesterol assay C. Ultracentrifuge the sample and repeat the HDL cholesterol on the infranate. Use the new result to calculate the LDL cholesterol D. Repeat the HDL cholesterol using the manganese heparin precipitation method. Use the new result to calculate the LDL cholesterol

B An accurate LDL cholesterol can be reported, if the direct (detergent) method for LDL cholesterol is employed. These methods are not subject to interference by triglycerides at a concentration below 700 mg/dL. Harr, Robert R. Medical Laboratory Science Review (Page 261). F.A. Davis Company. Kindle Edition.

A 5-year-old nonimmunized male with a persistent cough, fever, and flulike symptoms was admitted to the hospital. Nasopharyngeal swabs were cultured on 15% blood, chocolate, Bordet-Genjou, and Regan-Lowe (with 10% charcoal) agars. All media grew a gram-negative coccobacillus. Carbohydrate and biochemical tests were negative. What is the most likely identification? A. Haemophilus influenza B. Bordetella pertussis C. Haemophilus parainfluenzae D. Bordetella bronchiseptica

B B. pertussis, the cause of whooping cough, is highly contagious during the 5-10 day period after acquisition. The incidence of whooping cough is greater in nonimmunized individuals, and therefore, is higher in children under 1 year of age. B. bronchiseptica is only rarely found in humans, but may cause respiratory disease in animals. Unlike B. pertussis it is positive for nitrite, urease, and motility. Harr, Robert R. Medical Laboratory Science Review (Page 413). F.A. Davis Company. Kindle Edition.

Which of the following situations is likely to cause an error when weighing with an electronic analytical balance? A. Failure to keep the knife edge clean B. Failure to close the doors of the balance before reading the weight C. Oxidation on the surface of the substitution weights D. Using the balance without allowing it to warm up for at least 10 minutes

B Electronic balances do not use substitution weights or knife edges to balance the weight on the pan. Instead, they measure the displacement of the pan by the weight on it using electromagnetic force to return it to its reference position. Regardless of the type of balance used, all need to be located on a firm weighing table free of vibration. Doors must be closed to prevent air currents from influencing the weighing, and the pan and platform must be clean and free of dust and chemical residue. Harr, Robert R. Medical Laboratory Science Review (Page 189). F.A. Davis Company. Kindle Edition.

Which statement about TSH and T4 in early pregnancy is correct? A. TSH and thyroid hormones fall B. TSH falls and thyroid hormones rise C. TSH and thyroid hormones both rise D. TSH rises and thyroid hormones fall

B Estrogens released in pregnancy cause an increase in TBG, which causes an increase in total T 4 and T 3 . In early pregnancy, the hCG produced by the placenta stimulates the thyroid, causing an increase in free thyroid hormones. This suppresses TSH production. In the second trimester, as hCG diminishes, free T 4 levels fall, and may be lower than 0.8 ng/dL, the lower limit of the adult reference range due to expansion of the blood volume. Therefore, both TSH and free T 4 should be evaluated during pregnancy using trimester-specific reference ranges. In early pregnancy, a TSH above the first- trimester reference range should be followed up with free T 4 and thyroid peroxidase antibody levels to assess the need for thyroid treatment. Harr, Robert R. Medical Laboratory Science Review (Page 293). F.A. Davis Company. Kindle Edition.

An antibody screen is reactive at IAT phase of testing using a three-cell screen and the autocontrol is negative. What is a possible explanation for these results? A. A cold alloantibody B. High-frequency alloantibody or a mixture of alloantibodies C. A warm autoantibody D. A cold and warm alloantibody

B High-frequency alloantibodies or a mixture of alloantibodies may cause all three screening cells to be positive. A negative autocontrol would rule out autoantibodies. Harr, Robert R. Medical Laboratory Science Review (Page 140). F.A. Davis Company. Kindle Edition.

An India ink test was performed on CSF from an HIV-infected male patient. Many encapsulated yeast cells were seen in the centrifuged sample. Further testing revealed a positive urease test and growth of brown colonies on niger-seed agar. The diagnosis of meningitis was caused by which yeast? A. Candida albicans B. Cryptococcus neoformans C. Cryptococcus laurentii D. Candida tropicalis

B Immunocompromised patients are at risk for invasion of Cryptococcus neoformans. The polysaccharide capsule of C. neoformans is not recognized by phagocytes, which allow patients with impaired cell-mediated immunity to become readily infected with C. neoformans. Harr, Robert R. Medical Laboratory Science Review (Page 452). F.A. Davis Company. Kindle Edition.

A gram-negative rod is recovered from a catheterized urine sample from a nursing home patient. The lactose-negative isolate tested positive for indole, urease, ornithine decarboxylase, and phenylalanine deaminase and negative for H2 S. The most probable identification is: A. Edwardsiella spp. B. Morganella spp. C. Ewingella spp. D. Shigella spp.

B Morganella are biochemically similar to Proteus spp., both being lactose negative, motile, and positive for phenylalanine deaminase and urease. However, Morganella can be differentiated from Proteus spp. based upon H2 S, indole, ornithine decarboxylase, and xylose fermentation. Ewingella spp. are usually positive (70%) for lactose fermentation, whereas the other three genera are lactose negative. Harr, Robert R. Medical Laboratory Science Review (Page 394). F.A. Davis Company. Kindle Edition.

Which set of results is consistent with uncompensated respiratory alkalosis? A. pH 7.70, HCO3 30 mmol/L, PCO2 25 mm Hg B. pH 7.66, HCO3 22 mmol/L, PCO2 20 mm Hg C. pH 7.46, HCO3 38 mmol/L, PCO2 55 mm Hg D. pH 7.36, HCO3 22 mmol/L, PCO2 38 mm Hg

B Respiratory alkalosis is caused by hyperventilation, inducing low PCO2 . Very often, in the early phase of an acute respiratory disturbance, the kidneys have not had time to compensate, and the bicarbonate is within normal limits. In answer A, the bicarbonate is high and PCO2 low; thus, both are contributing to alkalosis and this would be classified as a combined acid-base disturbance. In answer C, the pH is almost normal, and both bicarbonate and PCO2 are increased. This can occur in the early stage of a metabolic acid- base disturbance when full respiratory compensation occurs or in a combined acid-base disorder. In answer D, both bicarbonate and PCO2 are within normal limits (22-26 mmol/L, 35-45 mm Hg, respectively) as is the pH. Harr, Robert R. Medical Laboratory Science Review (Page 193). F.A. Davis Company. Kindle Edition.

A leg-wound culture from a hospitalized 70-year-old diabetic man grew motile, lactose-negative colonies on MacConkey agar. Given the following biochemical reactions at 24 hours, what is the most probable organism? H2 S (TSI) = Neg Indole = Neg MR = Neg VP = + DNase = + Citrate = + Urease = Neg Phenylalanine deaminase = Neg Ornithine and lysine decarboxylase = + Arginine decarboxylase = Neg Gelatin hydrolysis = + A. Proteus vulgaris B. Serratia marcescens C. Proteus mirabilis D. Enterobacter cloacae

B S. marcescens has been implicated in numerous nosocomial infections and is recognized as an important pathogen with invasive properties. Gelatin hydrolysis and DNase are positive for both the Proteusspp. and Serratia, but the negative urease and phenylalanine deaminase are differential. E. cloacae does not produce DNase, gelatinase, or lysine decarboxylase. Harr, Robert R. Medical Laboratory Science Review (Page 397). F.A. Davis Company. Kindle Edition.

A major crossmatch and screening cells are 2+ at IS, 1+ at 34 degrees Celsius, and negative at the IAT phase. Identify the most likely problem. A. Combination of antibodies B. Cold alloantibody C. Rouleaux D. Test erro

B The reaction pattern fits that of a cold antibody reacting at the IS phase and of sufficient titer to persist at 37°C incubation. The reactions disappear in the IAT phase. Harr, Robert R. Medical Laboratory Science Review (Page 143). F.A. Davis Company. Kindle Edition.

A chemistry test result from a chemotherapy patient was within normal limits on Tuesday. The same test was reported as abnormal on Monday ("flagged" high and approaching a critical value). The technologist performing the test noted a delta-check error and remembered that both controls ran much higher on Monday although they were within acceptable limits. The technologist's decision to follow-up this discrepancy before reporting the results is an example of which domain of behavioral objectives? A. Cognitive B. Affective C. Psychomotor D. Organizational

B The technologist chose to investigate the situation in order to resolve a discrepancy. The responding, valuing, and characterization refer to the affective domain in dealing with the problem presented here. In doing so, a rule-based process is followed that includes evaluation of the specimen, instrument performance, potential sources of interference (such as the effects of drugs), and physiological variation before determining whether to report the result, repeat the test, or call for a new specimen. Harr, Robert R. Medical Laboratory Science Review (Page 524). F.A. Davis Company. Kindle Edition.

Which of the following questions is allowable during a pre-employment interview? A. How many times have you been pregnant? B. Have you been convicted of any felonies? C. Does your husband belong to any religious societies? D. Are you planning to use the hospital day care center?

B Title VII of the Civil Rights Act of 1964 states that questions are permissible during interviews if they are related to legitimate occupational qualifications. Inquiries concerning convictions for drug use or theft are legitimate questions when hiring a laboratory night supervisor or other individuals who will utilize controlled substances. Harr, Robert R. Medical Laboratory Science Review (Page 526). F.A. Davis Company. Kindle Edition.

In order to prove exclusion in DNA paternity testing, why must two genes be identified that must come from the biological father and did not? A. A single exclusion can result from laboratory error B. A single exclusion can result from germ line mutation within one locus being tested C. The biological father may be a blood relative to the alleged father D. The biological mother may be different than the purported mother

B Two exclusions are needed rather than one to be 100% certain of nonpaternity because of the rare possibility of a mutation having occurred in one of the loci being tested. Loci used for DNA testing are sufficiently polymorphic that the mother's sample is not necessary to determine paternity. Exclusion is based on the premise that the biological father must have at least one allele in common with the child at each locus. Harr, Robert R. Medical Laboratory Science Review (Page 518). F.A. Davis Company. Kindle Edition.

Which of the following conditions will cause erroneous Cai results? Assume the samples are collected and stored anaerobically, kept at 4 degrees Celsius until measurement, and stored for no longer than 1 hour. A. Slight hemolysis during venipuncture B. Assay of whole blood collected in sodium oxalate C. Analysis of serum in a barrier gel tube stored at 4 degrees Celsius until the clot has formed D. Analysis of whole blood collected in sodium heparin, 20U/mL (low-heparin tube)

B Unlike Pi , the intracellular calcium level is not significantly different from plasma calcium, and calcium is not greatly affected by diet. Whole blood collected with 5-20 U/mL heparin and stored on ice no longer than 2 hours is the sample of choice for Cai . Blood gas syringes prefilled with 100 U/mL heparin should not be used because the high heparin concentration will cause low results. Citrate, oxalate, and ethylenediaminetetraacetic acid (EDTA) must not be used because they chelate calcium. Serum may be used provided that the sample is iced, kept capped while clotting, and assayed within 2 hours (barrier gel tubes may be stored longer). Harr, Robert R. Medical Laboratory Science Review (Page 200). F.A. Davis Company. Kindle Edition.

A curved gram-negative rod producing oxidase-positive colonies on blood agar was recovered from a stool culture. Given the following results, what is the most likely identification? Lysine decarboxylase = + rginine decarboxylase = Neg Indole = + KIA = Alk/Acid VP = Neg Lactose = Neg Urease = ± String test = Neg TCBS agar = Green colonies A. Vibrio cholerae B. Vibrio parahaemolyticus C. Shigella spp. D. Salmonella spp.

B V. parahaemolyticus appear as green colonies on TCBS agar, whereas V. cholerae appear as yellow colonies on TCBS. V. cholerae is the only Vibrio species that causes a positive string test. In the test, a loopful of bacterial colonies is suspended in sodium deoxycholate, 0.5%, on a glass slide. After 60 seconds, the inoculating loop is lifted out of the suspension. V. cholerae forms a long string resembling a string of pearls. Salmonella spp. and Shigella spp. are oxidase negative. Harr, Robert R. Medical Laboratory Science Review (Page 406). F.A. Davis Company. Kindle Edition.

When a therapeutic drug is suspected of causing toxicity, which specimen is the most appropriate for an initial investigation? A. Trough blood sample B. Peak blood sample C. Urine at the time of symptoms D. Gastric fluid at the time of symptoms

B When a drug is suspected of toxicity, the peak blood sample (sample after absorption and distribution are complete) should be obtained because it is most likely to exceed the therapeutic limit. If the peak level is above the upper therapeutic limit, then toxicity is confirmed, and the drug dose is lowered. If the peak drug concentration is within the therapeutic range, toxicity is less likely, but cannot be ruled out. A high concentration of free drug, the presence of active metabolites, and abnormal response to the drug are causes of drug toxicity that may occur when the blood drug level is within the published therapeutic range. Harr, Robert R. Medical Laboratory Science Review (Page 298). F.A. Davis Company. Kindle Edition.

SITUATION: An emergency trauma patient requires transfusion. Six units of blood are ordered stat. There is no time to draw a patient sample. O-negative blood is released. When will compatibility testing be performed? A. Compatibility testing must be performed before blood is issued B. Compatibility testing will be performed when a patient sample is available C. Compatibility testing may be performed immediately using donor serum D. Compatibility testing is not necessary when blood is released in emergency situations

B When patient serum is available, it will be crossmatched with donor cells. Patient serum might contain antibodies against antigens on donor cells that may destroy donor cells. If an incompatibility is discovered, the problem will be reported immediately to the patient's physician. Harr, Robert R. Medical Laboratory Science Review (Page 140). F.A. Davis Company. Kindle Edition.

Which Bacillus species would not have a wide zone lecithinase reaction? Bacillus cereus Bacillus subtilis Bacillus mycoides Bacillus anthracis

Bacillus subtilis Of the Bacillus species listed in this exercise, only Bacillus subtilis fails to hydrolyze lecithin and therefore would not show the zone of hydrolysis. Bacillus cereus, Bacillus mycoides and Bacillus anthracis all give a positive lecithin (wide zone) reaction. Question Difficulty: Level 8

Taenia solium Taenia solium is the correct response. Although the spherical ova with their thick, striate shell and internal hooklets does not rule out Taenia saginata, the scolex of T. solium, with its distinctive rostellum armed with a ring of hooklets, serves to exclude T. saginata, the scolex of which is flat and rounded and devoid of an armed rostellum. Taenia saginata ova are similar in appearance to those of T. solium, with a thick striated shell and three pairs of hooklet observed interiorly. Distinctive is the scolex of the adult worm with a round, smooth anterior end devoid of an armed rostellum. Hymenolepis nana ova have a thin outer non-striated shell and an inner membrane within which three pairs of hooklets are contained. The scolex of the adult worm also has an armed rostellum, but in contrast to T. solium, is small and projects outward. Diphyllobothrium latum ova are large (up to 70 µm), and have a thin smooth shell with a distinctive, inconspicuous non-shouldered operculum at one end. The scolex of the adult worm is long and narrow with a dorso-ventral groove surrounded on either side by lateral lip-like folds. Question Difficulty: Level 1

Based on the morphologic features of this 40 µm (in diameter) ovum, as seen in the upper photomicrograph with the accompanying scolex of the adult worm illustrated in the lower image, select the presumptive identification of this cestode from the multiple choice answers listed below. Taenia saginata Taenia solium Hymenolepis nana Diphyllobothrium latum

Chryseobacterium spp. The OF dextrose reactions indicate that the bacterial species is a non-oxidizer. The positive urease reaction would lead one immediately to select either Bordetella bronchiseptica or Oligella ureolytica; however, both of these species reduce nitrates to nitrites. The left tube of the nitrate pair shows no red pigment, indicating that nitrates were not reduced to nitrites. The red pigment only appears in the tube after the addition of zinc dust. The zinc reduces nitrates to nitrites, confirming that nitrates were still unchanged in the original tube. None of the Moraxella species hydrolyze urea. In fact, all of the reactions shown here, including the positive urease, can be produced by Chryseobacterium spp., which is the correct response. Question Difficulty: Level 7

Based on the reactions observed in the tubes shown in the photograph (including open and closed OF dextrose and a positive nitrate reaction only after addition of zinc dust, as shown in the right tube of the pair labeled "Nit"), the most likely identification is: Bordetella bronchiseptica Chryseobacterium spp. Moraxella osloensis Oligella ureolytica

Severe infection The image in this question shows Dohle bodies in the cytoplasm of the neutrophils. Dohle bodies are oval, blue inclusions, and are 1 to 3 µm in diameter. They are highly associated with severe infections, burns, and cancer (due to toxic drugs). Dohle bodies can also be found in conjunction with toxic granulation and toxic vacuolization. Pelger-Huet anomaly presents with hyposegmentation of the nucleus in granulocytes. The nucleus in Pelger-Huet anomaly can be single lobed or bi-lobed (pince-nez, granny glasses). Infectious mononucleosis typically presents with an increased number of reactive lymphocytes in the peripheral blood smear. Myeloperoxidase deficiency does not cause an abnormality in appearance of Wright stained neutrophils. Question Difficulty: Level 7

Based on the white blood cells in the peripheral blood smear image, which condition would most likely be associated with this image? Severe infection Pelger-Huet anomaly Infectious mononucleosis Myeloperoxidase deficiency

Which of the following describes a beta thalassemia genotype β+/β? Beta thalassemia silent carrier Beta thalassemia minor Beta thalassemia intermedia Beta thalassemia major

Beta thalassemia minor β+/β denotes one partially deleted or inactive beta chain gene and one fully functional beta gene. This results in beta thalassemia minor (βo/β can also phenotype as beta thalassemia minor). This genotype causes decreased production of beta chains and a mild, asymptomatic anemia. Beta thalassemia minima (βsc/β) is an asymptomatic beta thalassemia (silent carrier). Beta thalassemia intermedia (βo/β+, β+/β+, or βo/β) causes a moderate anemia. Beta thalassemia major (βo/βo, βo/β+, or β+/β+ ), also known as Cooley's anemia, causes a severe anemia approximately six months after birth. Question Difficulty: Level 9

Which of the following tests is used to quantify a coagulation inhibitor? Prothrombin time Thrombin time Mixing study Bethesda assay

Bethesda assay The Bethesda assay is used to measure the titer and activity of the inhibitor present in a patient's sample. Prothrombin time is an initial screening procedure for bleeding disorders and a test used for monitoring anticoagulant therapy. A thrombin time is used to detect heparin interference in an aPTT mixing study. A mixing study is performed to detect the presence of a factor deficiency or coagulation inhibitor, but does not quantify the result. If the mixing study shows correction (return to normal values), a factor deficiency is suspected. However, if the mixing study fails to show correction, a coagulation inhibitor is suspected. Question Difficulty: Level 7

All of the following serological test results may occur in a patient experiencing a hemolytic transfusion reaction due to the presence of a clinically significant Rh antibody such as anti-c EXCEPT: Optimal reaction at 37°C or AHG phase. Preference to react with RBCs possessing a double-dose of Rh antigen. Binding complement. Positive DAT result.

Binding complement. Generally, Rh antibodies do not bind complement due to the positioning of Rh antigens on the RBC surface. Rh antigens do not sit close enough to allow for Rh (IgG class) antibodies to attach. Therefore, complement-mediated intravascular hemolysis does not occur. Serological testing for Rh antibody-mediated hemolytic transfusion reactions includes optimal reactivity at 37°C and a positive DAT result due to Rh antibodies belonging primarily to the IgG class. IgG antibodies are capable of crossing the placenta and coating fetal RBCs. Additionally, Rh antibodies demonstrate dosage and may show stronger reactivity with known cells possessing a double-dose of a corresponding Rh antigen (homozygous expression). Question Difficulty: Level 8

Which culture medium is specifically formulated to recover Salmonella typhi from stool specimens? Selenite broth Bismuth sulfite agar Salmonella/Shigella (SS) agar Deoxycholate citrate agar

Bismuth sulfite agar The correct answer is bismuth sulfite agar. Bismuth sulfite agar is a peptone enriched agar that contains bismuth sulfite and brilliant green which serve as inhibitors of most enteric bacteria except Salmonella typhi, and other salmonellae. Selenite broth is used to inhibit the growth of E.coli and other coliform bacilli, but it must be subcultured to another media, commonly bismuth sulfite agar. SS agar is selective for Salmonella and Shigella. Deoxycholate citrate agar is selective for Salmonella paratyphi. Question Difficulty: Level 7

All of the following factors would cause an increase erythrocyte sedimentation rate (ESR) values EXCEPT? Severe anemia Abnormal proteins (Rouleaux) Blood drawn into sodium citrate anticoagulant A slanted (not perpendicular) tube

Blood drawn into sodium citrate anticoagulant Either sodium citrate or EDTA are used for ESR testing since neither will have a positive or negative effect on the rate of red blood cell sedimentation. Severe anemia and abnormal proteins (Rouleaux) can cause an increased ESR value. A slanted tube can accelerate the sedimentation rate by up to 30%. Question Difficulty: Level 7

This species is the most commonly reported laboratory-acquired bacterial infection and must be handled in a class II or higher biological safety cabinet. They are small gram negative coccobacilli that are strict aerobes and will grow on Sheep Blood Agar and Chocolate agar. They are nonmotile, catalase, urease, and nitrate positive and most strains are oxidase positive. From the choices below, please select the organism matching the microscopic and biochemical reactions listed: Brucella species Kingella species Moraxella species Acinetobacter species

Brucella species Brucella species are pathogenic for humans and causes a disease called brucellosis especially in Mediterranean and Persian Gulf countries, India, and parts of Mexico and Central and South America. The organisms are capable of surviving for extended periods of time in soil, animals, milk and cheese. These organism will also grow on Maconkey agar. Kingella species are found as normal microbiota of human upper respiratory tract. Can be involved in serious infections in children less than 4 years old such as osteoarthritic infections. These organisms are catalase and urease negative and oxidase positive and will not grow on Maconkey agar. Moraxella species are considered to be normal mucosal microbiota with low virulence. These organisms are catalase positive and show variable reactions with nitrate reduction. Some organisms within the group may grow on Maconkey as non-lactose fermenters. Acinetobacter species are widely distributed in nature and capable of surviving on inanimate objects for extended periods of time and thus makes them problematic for health care settings. They are opportunitstic pathogens mostly infecting patients in intensive care units and long term care facilities. These organisms are nonmotile, nitrate negative, and show variable reactions with urea. Question Difficulty: Level 8

Pappenheimer (siderotic) bodies Pappenheimer bodies (when found with Wright-Giemsa stain), also known as siderotic granules (when found with Prussian blue stain), are iron-containing granules that aggregate with mitochondria and are deposited in RBC or normoblast cytoplasm. These inclusions are small and irregular and are found only in pathological states as thalassemia and sideroblastic anemias (upper image). Wright-Giemsa stain defines the cytoplasmic content (protein) of the Pappenheimer bodies, but Prussian blue staining is necessary to define the iron content, the essence of the siderotic granules (lower image). Pappenheimer bodies lie typically in small clusters (upper image) and tend to locate at the periphery of the red cell cytoplasm. A cluster is typically smaller than a single Howell-Jolly body. When iron granules are found surrounding the nucleus of red blood cell precursors in the bone marrow, it is termed ringed sideroblasts. The excess of iron surrounding the nucleus is due to the inappropriate incorporation of iron into the developing cell. This phenomenon is highly associated with sideroblastic anemia. Cabot rings are ring, figure eight, or loop shaped structures. They are red or reddish purple. They are remnants of microtubules from the mitotic spindle. Cabot rings can be seen in pernicious anemia and lead poisoning. Howell Jolly bodes are dark-blue/purple round inclusions. They are DNA nuclear remnants. If a cell contains Howell Jolly bodies, it is typically only one or two. Howell Jolly bodies are seen in hemolytic anemias and pernicious anemia. Malaria parasites are found inside red blood cells. The parasites can appear as ring forms with one or two chromatin dots or as gametes or merozoites. Infected red blood cells are destroyed during the reproductive process of the malarial parasites. The infected cells can be seen on Wright-Giemsa stain, not supravital stains. Question Difficulty: Level 4

By utilizing a Prussian Blue stain, which of the following red blood cell inclusions would be identifiable if present? Note: Upper image = Wright-Giemsa stain Lower image = Prussian Blue stain Cabot rings Pappenheimer (siderotic) bodies Howell Jolly bodies Malarial parasites

SITUATION: A pregnant female was seen by her physician who suspected a molar pregnancy. An hCG test was ordered and found to be low. The sample was diluted 10-fold and the assay was repeated. The result was found to be grossly elevated. What best explains this situation? A. The wrong specimen was diluted B. A pipeting error was made in the first analysis C. Antigen excess caused a falsely low result in the undiluted sample D. An inhibitor of the antigen-antibody reaction was present in the sample

C Assays of intact hCG are double antibody sandwich immunoassays. One antibody reacts with the α subunit and the other with the β subunit. In assays where both antibodies are added together, a process called the "hook effect" is known to occur. In extreme antigen excess, the hCG saturates both antibodies, preventing sandwich formation. This results in a falsely low measurement of hCG. Harr, Robert R. Medical Laboratory Science Review (Page 364). F.A. Davis Company. Kindle Edition.

Cultures obtained from a dog bite wound produced yellow, tan, and slightly pink colonies on blood and chocolate agar with a margin of fingerlike projections appearing as a film around the colonies. Given the following results at 24 hours, which is the most likely organism? Oxidase = + Catalase = + Growth on MacConkey agar = Neg Motility = Neg A. Actinobacillus spp. B. Eikenella spp. C. Capnocytophaga spp. D. Pseudomonas spp.

C Capnocytophaga gingivalis, C. sputigena, and C. ochracea are part of the normal oropharyngeal flora of humans; however, C. canimorsus and C. cynodegmi (formerly CDC groups DF-2 and DF-2-like bacteria) are associated with infections resulting from dog bite wounds. Harr, Robert R. Medical Laboratory Science Review (Page 409). F.A. Davis Company. Kindle Edition.

A 20-year-old female college student complained of a sore throat and extreme fatigue. The physician noted lymphadenopathy and ordered a rapid test for infectious mononucleosis antibodies that was negative. Bacterial cultures were negative, as were serological tests for influenza A and B, HIV-1, CMV, hepatitis B, and antistreptolysin O. What would be the next line of viral testing to establish a diagnosis? A. Herpes simplex B. Rubella C. Epstein-Barr D. West Nile

C Epstein-Barr virus serological testing for IgM-VCA (viral capsid antigen) during the acute phase would be indicated because testing for infectious mononucleosis antibodies may or may not be positive. Patients who present with an infectious mononucleosis-like syndrome should be tested for both EBV and CMV. Both viruses cause the same symptoms during the acute phase of the illness. Harr, Robert R. Medical Laboratory Science Review (Page 459). F.A. Davis Company. Kindle Edition.

A donor bag is half filled during donation when the blood flow stops. Select the correct course of action. A. Closely observe the bag for at least 3 minutes; if blood flow does not resume, withdraw the needle B. Remove the needle immediately and discontinue the donation C. Check and reposition the needle if necessary; if blood flow does not resume, withdraw the needle D. Withdraw the needle and perform a second venipuncture in the other arm

C If blood flow has stopped, check the needle first. If blood flow does not resume after repositioning, then withdraw the needle and discontinue the donation. Do not perform a second venipuncture on the donor. Harr, Robert R. Medical Laboratory Science Review (Page 156). F.A. Davis Company. Kindle Edition.

Three consecutive stool cultures from a 25-year-old male patient produced scant normal fecal flora on MacConkey and Hektoen agars. However, colonies on CIN agar (cefsulodin-irgasan-novobiocin) displayed "bulls-eye" colonies after 48 hours incubation. The patient had been suffering from enterocolitis with fever, diarrhea, and abdominal pain for 2 days. What is the most likely identification of this gram-negative rod? A. E. coli B. Proteus mirabilis C. Yersinia enterocolitica D. Klebsiella pneumoniae

C Most members of the Enterobacteriaceae family produce detectable growth on MacConkey agar within 24 hours. Yersinia enterocolita produces non-lactose-fermenting colonies on MacConkey agar, salmon-colored colonies on Hektoen agar, and yellow or colorless colonies on XLD agar. If Yersinia enterocolitica is suspected, specialized agar (CIN) is employed. The typical bulls-eye colonies, dark red with a translucent border, can be confused with Aeromonas spp. that appear similarly on CIN agar. To differentiate, an oxidase test must be performed, since Yersinia spp. are oxidase negative and Aeromonas spp. are oxidase positive. Harr, Robert R. Medical Laboratory Science Review (Page 398). F.A. Davis Company. Kindle Edition.

A person presents with a cushingoid appearance and an elevated 24-hour urinary cortisol level. The plasma adrenocotropic hormone (ACTH) is very elevated, and the physician suspects the cause is ectopic ACTH production. Which test would be most useful in substantiating this diagnosis? A. Plasma cortisol B. CA-50 C. Alkaline phosphatase isoenzymes D. AFP

C Most often, ectopic ACTH production occurs in lung cancer. Tumors of the lung are often associated with the production of placental-like alkaline phosphatase, and a positive finding would support the diagnosis of an ectopic (nonpituitary) source of ACTH. Many other tumor markers, including neuron-specific enolase and parathyroid hormone-related protein, are also increased in lung cancers. CA-50 (along with CA-19-9) shares the same antigenic determinant as Lewis A and is a marker for recurrence and treatment of gastrointestinal and pancreatic cancers. AFP is the predominant protein produced by the fetus, and plasma levels are increased primarily in yolk sac, liver, and testicular tumors. Harr, Robert R. Medical Laboratory Science Review (Page 305). F.A. Davis Company. Kindle Edition.

A woman who has had five pregnancies subsequently tests positive for HIV by Western blot. What is the most likely reason for this result? A. Possible cross-reaction with herpes or EBV antibodies B. Interference from medication C. Cross-reaction with HLA antigens in the antigen prepration D. Possible technical error

C Multiparous women often have HLA antibodies. The Western blot antigens are derived from HIV grown in human cell lines having HLA antigens. A cross reaction with HLA antigen(s) in the Western blot could have occurred. Harr, Robert R. Medical Laboratory Science Review (Page 90). F.A. Davis Company. Kindle Edition.

An EDTA blood sample is collected from a nonfasting person for a CBC. The physician collected the sample from the femoral vein because venipuncture from the arm was unsuccessful. He called the lab 15 minutes after the sample arrived and requested a lipid study including triglyceride, total cholesterol, HDL cholesterol, and LDL cholesterol. Which test results should be used to evaluate the patient's risk for coronary artery disease? A. Total cholesterol and LDL cholesterol B. LDL cholesterol and triglyceride C. Total cholesterol and HDL cholesterol D. Total cholesterol and triglyceride

C NCEP recommends a 12-hour fasting sample when screening persons for risk of coronary artery disease. However, if a fasting sample is unavailable, NCEP recommends performing the total cholesterol and HDL cholesterol because these tests are least affected by recent ingestion of food. If the total cholesterol is ≥ 200 mg/dL or the HDL cholesterol is < 40 mg/dL, then testing for LDL cholesterol and triglycerides should be performed when a fasting sample can be obtained. An EDTA plasma sample is acceptable for most enzymatic cholesterol and triglyceride assays. Harr, Robert R. Medical Laboratory Science Review (Page 259). F.A. Davis Company. Kindle Edition.

A patient has the following arterial blood gas results: pH = 7.56 PO2 = 100 mm Hg PCO2 = 25 mm Hg HCO3- = 22 mmol/L These results are most likely the result of which condition? A. Improper specimen collection B. Prolonged storage C. Hyperventilation D. Hypokalemia

C The pH is alkaline (reference range 7.35-7.45) and this can be caused by either low PCO2 or increased bicarbonate. This patient has a normal bicarbonate (reference range 22-26 mmol/L) and a low PCO2 (reference range 35-45 mm Hg). Low PCO2 is always caused by hyperventilation, and therefore, this is a case of uncompensated respiratory alkalosis. The acute stages of respiratory disorders are often uncompensated. Prolonged storage would cause the pH and PO2 to fall, and the PCO2 to rise. Hypokalemia causes alkalosis, but usually is associated with the retention of CO2 as compensation. Harr, Robert R. Medical Laboratory Science Review (Page 195). F.A. Davis Company. Kindle Edition.

There are few procedures considered STAT in parasitology. The most obvious situation would be: A. Ova and parasite examination for giardiasis B. Baermann's concentration for strongyloidiasis C. Blood films for malaria D. Culture of amoebic keratitis

C The request for blood films for malaria should always be considered a stat request. Any laboratory providing these services should be available 24 hours a day, 7 days a week. In cases of P. falciparum malaria, any delay in diagnosing the infection could be fatal for the patient. Harr, Robert R. Medical Laboratory Science Review (Page 470). F.A. Davis Company. Kindle Edition.

A patient's red cells forward as group O, serum agglutinates B cells (4+) only. Your next step would be: A. Extend reverse typing for 15 minutes B. Perform an antibody screen including a room-temperature incubation C. Incubate washed red cells with anti-A1 and anti-A,B for 30 minutes at room temperature D. Test patient's red cells with Dolichos biflorus

C The strong 4+ reaction in reverse grouping suggests the discrepancy is in forward grouping. Incubating washed red cells at room temperature with anti-A and anti-A,B will enhance reactions. Harr, Robert R. Medical Laboratory Science Review (Page 127). F.A. Davis Company. Kindle Edition.

When performing a sweat chloride collection, which of the following steps will result in analytical error? A. Using unweighed gauze soaked in pilocarpine nitrate on the inner surface of the forearm to stimulate sweating B. Collecting more than 75 mg of sweat in 30 minutes C. Leaving the preweighed gauze on the inside of the arm exposed to air during collection D. Rinsing the collected sweat from the gauze pad using chloride titrating solution

C The sweat chloride procedure requires the application of pilocarpine to stimulate sweating, and the use of iontophoresis (application of 0.16-mA current for 5 minutes) to bring the sweat to the surface. After iontophoresis, the skin on the inner surface of the forearm is washed with deionized water and dried, and a preweighed pair of 2-in. 2 pads is taped to the skin. During the 30-minute collection of sweat, the gauze must be completely covered to prevent contamination and loss of sweat by evaporation. The Gibson-Cooke reference method for sweat chloride uses the Schales and Schales method (titration by Hg[NO3 ] 2 with diphenylcarbazone indicator) to assay 1.0 mL of sweat eluted from the gauze with 5 mL of water. A Cotlove chloridometer is often used to measure sweat chloride. The sweat is eluted from the gauze with the titrating solution to facilitate measurement. Alternatively, a macroduct collection system may be used that does not require weighing. A minimum mass of 75 mg sweat is required for collection in gauze and 15 μL sweat for collection in macroduct tubing. Harr, Robert R. Medical Laboratory Science Review (Page 204). F.A. Davis Company. Kindle Edition.

A 68-year-old female diagnosed with neutropenia and inflammation of the left hand was typed as A positive, and received 1 packed red blood cell unit. The antibody screen was negative and crossmatch was compatible. During the transfusion, her pulse was 94, and blood pressure rose from 114/59 to 132/64. Her temperature rose from 37.1 degrees Celsius pretransfusion to 37.8 degrees 60 minutes after starting transfusion, then to 38.1 upon completion. A post-transfusion specimen yielded plasma that was neither hemolyezed nor icteric, and a negative DAT. Post-transfusion urinalysis gave a 1+ blood and protein with 10 RBCs/hpf microscopically. The clerical check was acceptable. What type of reaction most likely occurred as a result of transfusion? A. Allergic B. Circulatory overload C. Febril nonhemolytic D. Delayed hemolytic

C The temperature rose from 37.1°C to 38.1°C. The DAT was negative, and while blood was found on the urinalysis, microscopic red cells were also found. Since intact RBCs are not caused by a transfusion reaction, the cause of hematuria was not likely transfusion related. A febrile nonhemolytic reaction is highly consistent with both symptoms and posttransfusion test results. Harr, Robert R. Medical Laboratory Science Review (Page 146). F.A. Davis Company. Kindle Edition.

Patient DB received 2 units of group A-positive red cells 2 days ago. Two days later, he developed a fever and appeared jaundiced. His blood type was A positive. A transfusion reaction workup was ordered. There were no clerical errors detected. A post-transfusion specimen was collected and a DAT performed. The DAT was positive with monospecific anti-IgG. The plasma was also hemolyzed. An antibody screen and panel studies revealed the presence of anti-Jk^b (postspecimen). The antibody screen on the pretransfusion specimen was negative. Which of the following explain the positive DAT? A. The donor cells had a positive DAT B. The donor cells were polyagglutinable C. The donor cells were likely positive for the Jk^b antigen D. The recipient cells were likely positive for the Jk^b antigen

C This is an example of an anamnestic reaction where the patient was most likely exposed to the Jk b antigen at some point in his life, and upon re-exposure to the antigen, the antibody titer rose to detectable levels. This resulted in a positive DAT and post-transfusion antibody screen. Harr, Robert R. Medical Laboratory Science Review (Page 146). F.A. Davis Company. Kindle Edition.

A woman begins to breath rapidly while donating blood. Choose the correct course of action. A. Continue the donation; rapid breathing is not a reason to discontinue a donation B. Withdraw the needle; raise her feet, and administer ammonia C. Discontinue the donation and provide a paper bag D. Tell her to sit upright and apply a cold compress to her forehead

C This woman is hyperventilating; therefore, the donation should be discontinued. A paper bag should be provided for the donor to breathe into in order to increase the carbon dioxide in the donor's air. Harr, Robert R. Medical Laboratory Science Review (Page 155). F.A. Davis Company. Kindle Edition.

SITUATION: A 5-mL urine specimen is submitted for routine urinalysis and analyzed immediately. The SG of the sample is 1.012 and the pH is 6.5. The dry reagent strip test for blood is a large positive (3+) and the microscopic examination shows 11-20 RBCs per HPF. The leukocyte esterase reaction is a small positive (1+), and the microscopic examination shows 0-5 WBCs per HPF. What is the most likely cause of these results? A. Myoglobin is present in the sample B. Free hemoglobin is present C. Insufficient volume is causing microscopic results to be underestimated D. Some WBCs have been misidentified as RBCs

C Given the SG and pH, most RBCs and WBCs will be intact. Both the RBC and WBC counts are lower than expected from the dry reagent strip results. Myoglobin or free hemoglobin may account for the poor correlation between the blood reaction and the RBC count, but this does not explain the lower than expected WBC count. Microscopic reference ranges are based upon concentrating a uniform volume of sediment from 12 mL of urine. When less urine is used, falsely low results will be obtained unless corrective action is taken. The specimen should be diluted with normal saline to 12 mL, then centrifuged at 450 × g for 5 minutes. Sediment should be prepared according to the established procedure and the results multiplied by the dilution factor (in this case, 12 ÷ 5, or 2.4). Harr, Robert R. Medical Laboratory Science Review (Page 343). F.A. Davis Company. Kindle Edition.

What would be the most likely designation by the WHO for the FAB AML M2 by the French-American-British classification? A. AML with t(15;17) B. AML with mixed lineage C. AML with t(8;21) D. AML with inv(16)

CAML with t(8;21) is classified under the category of AML with Recurrent Genetic Abnormalities by the WHO. This translocation occurs in up to 15% of cases of AML and may be the most common translocation. The AML1-ETO translocation occurs chiefly in younger patients and often in cases of acute myeloblastic leukemia with maturation, FAB M2. The translocation involves the fusion of the AML1 gene on chromosome 21 with the ETO gene on chromosome 8. Harr, Robert R. Medical Laboratory Science Review (Page 25). F.A. Davis Company. Kindle Edition.

Which of the following is the proper designation for the pluripotential stem cell that is a precursor for both myeloid and lymphoid cell lines? CFU-S CFU-GEMM G-CSF CFU-GM

CFU-S CFU-S stands for colony forming unit spleen - it is the pluripotential stem cell that gives rise to all cell lines. CFU-GEMM is a multilineage precursor for granulocyte, erythrocyte, macrophage, and megakaryocyte. G-CSF is the precursor committed to granulocyte cell lines. CFU- GM- precursor for granulocyte and monocyte cell lines. Question Difficulty: Level 8

Which of the following is not directly responsible for setting and monitoring competency requirements for laboratory personnel: CAP HCFA Joint Commission (formerly JCAHO) CLSI

CLSI CLSI provides laboratory standards but has no monitoring or regulatory authority. CAP College of American Pathologists can and does have monitoring or regulatory authority. HCFA the Health Care Finance Administration does have monitoring or regulatory authority over payment. Joint Commission (formerly JCAHO) can and does have monitoring or regulatory authority. Question Difficulty: Level 8

All of the following normal urine crystals are most often found in a urine that has a pH > 7 EXCEPT: Calcium oxalate Triple phosphate Ammonium biurate Calcium carbonate

Calcium oxalate Calcium oxalate crystals, as seen in in the image, are most often found in an acidic (pH < 7.0) urine. Triple phosphate crystals have a 'coffin lid' appearance and are found in alkaline (pH > 7.0) urine. Ammonium biurate crystals have a 'thorny apple' appearance and are found in alkaline urine. Calcium carbonate crystals have a 'dumbbell' appearance and are found in alkaline urine. Question Difficulty: Level 2

If a person comes in direct contact with an electrical source and sustains an electrical shock, which of the following actions should be taken to appropriately help the victim of electrical injury? Call a physician immediately. Avoid unplugging/disconnecting the source of the electricity. Lower the victim's head below the trunk of the body and elevate the legs. Cover the victim with a blanket or coat

Call a physician immediately. Lower the victim's head below the trunk of the body and elevate the legs. Cover the victim with a blanket or coat Call a physician immediately. Lower the victim's head to slightly lower than the trunk of the body, and elevate the legs. Cover the victim with a blanket or coat. Begin CPR if the victim's breathing and/or pulse has stopped or seems dangerously slow or shallow. The only incorrect answer is to leave the source of the electrical shock running. You would not want to avoid unplugging the source of electricity in this case. Safely unplugging the power supply/plug causing the electrical shock is actually one of the first steps in rescuing a victim of electrical injury. This should be done carefully, as not to cause electrical injury to the rescuer. Non-conductive materials should be used to unplug, such as leather belts, a folded newspaper, or an object made of rubber. Question Difficulty: Level 7

A fusiform-shaped, Gram negative, oxidase negative bacillus that produces colonies with marginal finger-like projections was recovered from the oral cavity of a patient with periodontal disease. The most likely identification is: Capnocytophaga canimorsus Capnocytophaga ochracea Actinobacillus actinomycetemcomitans Eikenella corrodens

Capnocytophaga ochracea Capnocytophaga ochracea, a commensal organism within the oral cavity of humans, may produce a variety of aminopeptidases, neuraminidases, and products that have direct toxic effects on neutrophils resulting in degradation of subgingival and periodontal tissue leading to periodontal disease. The fingerlike projections emanating from the colonies is known as "gliding motility", an additional factor that permits the organism to penetrate deeply into gingival fissures. Capnocytophaga canimorsus has a similar appearance to C. ochracea to culture; however, is indigenous in the oral cavity of dogs and causes human dog bite infections but not oral disease. Actinobacillus actinomycetemcomitans can also cause periodontal disease; however, the bacterial cells are not fusiform and the colonies do not produce gliding motility. Eikenella corrodens also inhabits the oral cavity of humans, but has none of the characteristics for C. ochracea as previously described. Question Difficulty: Level 7

Which of the following statement is INCORRECT regarding the bone marrow biopsy specimen? Bone marrow cellularity can be accurately determined Cellular morphologic detail can be determined. Bone marrow architecture can be examined Prussian blue staining could be used to evaluate iron stores, and diagnosis of anemia.

Cellular morphologic detail can be determined. Cellular morphologic details CANNOT be determined via bone marrow biopsies. Bone marrow cellularity can be determined accurately by comparing the amount of hematopoietic tissue with the amount of adipose tissue. Bone marrow core biopsy could be examined to reveal bone marrow architecture. Estimation of quantity of iron and its distribution is part of bone marrow examination. The Prussian blue stain provides the most direct means of assessing body iron stores. Question Difficulty: Level 8

Abnormal granulation can be seen in the cytoplasm of leukocytes in which of the following conditions? Pelger-Huët anomaly Pseudo-Pelger-Huët anomaly May-Hegglin anomaly Chediak-Higashi syndrome

Chediak-Higashi syndrome Chediak-Higashi syndrome is a rare fatal autosomal recessive disease. The disease is characterized by abnormal fusion of granules in hematopoietic cells that contain granules (granulocytes, monocytes, and lymphocytes). The fused granules are large and dysfunctional and result in recurrent bacterial infections. Pelger-Huët anomaly is an autosomal dominant disorder characterized by decreased nuclear segmentation of neutrophils. The neutrophils in PHA have normal granules and function normally. Pseudo-Pelger-Huët anomaly is a condition that occurs in patients with myelodysplasia and myeloproliferative disorders. There is hyposegmentation of the neutrophils but granule formation is normal. May-Hegglin anomaly is a rare, autosomal dominant platelet disorder in which the neutrophils have inclusions that are similar to Döhle bodies. Granule formation is normal, however, patients may have thrombocytopenia which results in abnormal bleeding. Question Difficulty: Level 8

The following is a spore-forming anaerobe that is associated with neutropenic enterocolitis: Clostridium septicum Porphyromonas spp. Bacteroides fragilis Fusobacterium nucleatum

Clostridium septicum Clostridium septicum is an anaerobic, spore-forming, Gram positive organism bacillus that has been associated with neutropenic enterocolitis. This organism is characterized as producing subterminal spores, gelatin positive, lecithinase and lipase negative, indole negative, and esculin positive. Porphyromonas spp. are anaerobic non-spore forming Gram negative bacilli that have been associated with endogenous infections associated with the intestinal tract. They characteristically produce pigmented colonies. Bacteroides fragilis are anaerobic non-spore forming Gram negative bacilli that have been associated with endogenous infections associated with the oral and gastrointestinal tract. It is the most commonly isolated anaerobic organism from clinical specimens. Fusobacterium nucleatum is anaerobic non-spore forming Gram negative bacillus that has been associated with endogenous infections of the head and neck region in relation to dental biofilms. Question Difficulty: Level 8

Within three days, at 25ºC, a sputum specimen placed on Sabouraud's dextrose agar with chloramphenicol and cycloheximide produced moist, grayish growth, with a white aerial mycelium. The patient had a history of travel to national parks in California. The questionable organism is MOST likely: Histoplasma capsulatum Blastomyces dermatitidis Coccidioides immitis Paracoccidiodes brasiliensis

Coccidioides immitis All of the dimorphic fungi listed here may cause pulmonary disease through inhalation of conidia. Although macroscopic morphology may be difficult to distinguish, growth rate differs, with C. immitis growing faster than the others listed. Coccidioides immitis can be isolated from sputum specimens of infected individuals. When grown on Sabouraud's agar at 25oC, it grows as a mold with white aerial mycelium in about 3 to 5 days. The mold form of C. immitis is known to produce arthroconidia which are "barrel-shaped" after 1 to 2 weeks of growth. C. immitis does not readily convert to its yeast form at 37oC. It is endemic to the San Joaquin Valley in California, and other semi-arid conditions. Histoplasma capsulatum is a slow grower. The microscopic mold form demonstrates echinulate macroconidia. It is endemic to river basins in the lower-U.S. Bronchial alveolar lavage specimens may be tested if pulmonary involvement is noted. Blastomyces dermatitidis has slow to moderate growth. The microscopic mold form demonstrates individual conidiophores supporting round/oval conidia, resembling "lollipops." It is endemic to the Mississippi and Ohio river valleys. Paracoccidiodes brasiliensis is a slow grower. It is endemic to Central and South America. The mold phase of P. brasiliensis produces small, conidia resembling other dimorphic fungi. The yeast phase produces multiple buds, resembling a "mariner's wheel." Question Difficulty: Level 7

The arrangement of erythrocytes on this peripheral blood smear can be associated with each of the following conditions EXCEPT: Multiple myeloma Cold agglutinin disorders Chronic inflammatory disorders Lymphoplasmacytic lymphoma

Cold agglutinin disorders The correct response is cold agglutinin disorders. Erythrocyte agglutination (clumping) rather than rouleaux formation appears in these disorders when cold reactive antibodies, most commonly IgM, are circulating in the plasma. Microscopically, cold agglultinin disorders demonstate large clumps of RBCs in contrast to the branching lines of RBCs seen in this image of rouleaux. The arrangement of the RBC's documented in the photograph is called rouleaux formation. Rouleaux resembles a stack of falling dominoes or coins. RBCs have a net negative charge on the surface of their plasma membranes. This negative charge helps to repel one RBC from another. Rouleaux formation is enhanced when positively charged plasma proteins are increased, particularly fibrinogen and gamma globulin. These positive proteins counteract the repulsive charge between RBCs. Multiple myeloma, chronic inflammatory disorders, and lymphoplasmacytic lymphoma are each responsible for increasing the concentration of these positively charged proteins leading to rouleaux. Question Difficulty: Level 8

Autoimmune hemolytic anemia The spherocytes that are shown in this image are not the tightly contained, densely staining microspherocytes of hereditary spherocytosis. Also, these spherocytes do not predominate in the field of red cells as they would in hereditary spherocytosis. The small, spherical, dense, orange-staining erythrocytes are spherocytes as found in immune hemolytic anemias. In these anemias the spleen attempts to remove the autoantibody from the red cells by "shaving" off a portion of cell membrane resulting in a reduced surface to volume ratio thus the cells appear spherocytic. The small red cells of iron deficiency anemia and thalassemia are pale staining and are hollow centrally. Microcytes of thalassemia may contain a small central density giving the appearance of a "target" or "Mexican hat". Pernicious is a megaloblastic anemia which is typically seen as a macrocytic, normochromic anemia. The appearance of spherocytes as in this photomicrograph are not typically part of the blood picture of PA. Question Difficulty: Level 6

Conditions in which erythrocytes as photographed here may be present in a peripheral blood smear include: Autoimmune hemolytic anemia Iron deficiency Beta thalassemia Pernicious anemia

Cystine-tellurite blood agar is recommended for the isolation of which organism? Yersinia enterocolitica Legionella pneumophilia Corynebacterium diphtheriae Francisella tularensis

Corynebacterium diphtheriae The correct answer is Corynebacterium diphtheriae. Cystine-tellurite blood agar is a differential and selective medium recommended for the isolation of C. diphtheriae. On this media, C.diphtheriae produces black/gray colonies since the tellurite is reduced intracellularly to tellurium. The cystine-tellurite culture plates should be observed after 18 to 24 hours of incubation at 37°C in a 5% carbon dioxide-enriched atmosphere. Yersinia enterocolitica does not require special media in order to be isolated, but is more biochemically reactive at room temperature than at 37°C. Media is often inoculated in duplicate, with one set being incubated at each temperature. When Legionella pneumophilia is suspected, samples are often inoculated onto BYCE agar or BYCE-based selective agar (with added antibiotics to inhibit other flora). Francisella tularensis does require cysteine for growth, but is able to grow on chocolate agar due to its enrichment with heme-containing growth enrichment. Question Difficulty: Level 7

Stenotrophomonas maltophilia and Burkholderia cepacia share each of the following characteristics EXCEPT: Decarboxylation of lysine Cytochrome oxidase activity Production of colonies with a yellow pigment Good growth on MacConkey agar

Cytochrome oxidase activity Cytochrome oxidase is the correct response. Stenotrophomonas maltophilia is cytochrome oxidase negative and Burkholderia cepacia is cytochrome oxidase positive. Both Burkholderia cepacia and Stenotrophomonas maltophilia were previously included in the genus Pseudomonas. These were the two pseudomonads that characteristically produced yellow colonies and decarboxylated lysine. The departure of Stenotrophomonas maltophilia from the genus was heralded by its lack of cytochrome oxidase activity. Most strains of Burkholderia cepacia are cytochrome oxidase positive, although the reaction may be weak in some cases. Therefore, of the characteristics listed, cytochrome oxidase activity is the only one that is different for the two species. Both organisms can decarboxylate lysine. Both organisms produce a yellow pigment. B. cepacia produces yellow, serrated colonies while S. maltophilia produces smooth, glistening yellow to tan colonies. Both species grow well on MacConkey agar. Question Difficulty: Level 8

A stool from a 2-year-old girl grew clear colonies on MacConkey agar, red colonies on XLD (without black centers), and green colonies on HE (without black centers). It is ornithine positive and indole negative. It should agglutinate in antisera of which serogroup of the somatic O antigen? A B C D

D The correct answer is D. Since the biochemical results are consistent with Shigella sonnei, you would expect agglutination with group D antisera. This isolate is the most common Shigella species found in the United States. Most patients in developed countries usually recover from infection without hospitalization due to the self-limiting disease that is generally characterized by fever and watery diarrhea. Shigella groups A (S.dysenteriae), B (S.flexneri), and C (S.boydii) are ornithine negative and usually indole positive. Question Difficulty: Level 7

Which AML cytogentic abnormality is associated with acute myelomonocytic leukemia with marrow eosinophilia under the WHO classification of AML with recurrent abnormalities? A. AML with t(15;17) B. AML with mixed lineage C. AML with t(8;21) D. AML with inv(16)

D AML with inv(16) has pericentric inversion of chromosome 16, and is associated with acute myelomonocytic leukemia with marrow eosinophilia, M4eo under the FAB system. The inv(16) results in the fusion of the CBFβ gene on 16q22 with the MYH11 gene on 16p13. Harr, Robert R. Medical Laboratory Science Review (Page 25). F.A. Davis Company. Kindle Edition.

A gram-positive (gram-variable), beaded organism with delicate branching was recovered from the sputum of a 20-year-old patient with leukemia. The specimen produced orange, glabrous, waxy colonies on Middlebrook's agar that showed partial acid-fast staining with the modified Kinyoun stain. What is the most likely identification? A. Rhodococcus spp. B. Actinomadura spp. C. Streptomyces spp. D. Nocardia spp.

D All of the listed organisms produce mycelium (aerial or substrate), causing them to appear branched when Gram stained, but only the Nocardia spp. are positive for modified acid-fast stain. Nocardia is an opportunistic pathogen, and cultures typically have a musty basement odor. Harr, Robert R. Medical Laboratory Science Review (Page 431). F.A. Davis Company. Kindle Edition.

A patient showed positive results with screening cells and 4 donor units. The patient autocontrol was negative. What is the most likely antibody? A. Anti-H B. Anti-S C. Anti-Kp^a D. Anti-k

D Anti-k (cellano) is a high-frequency alloantibody that would react with screening cells and most donor units. The negative autocontrol rules out autoantibodies. Anti-H and anti-S are cold antibodies and anti-Kpa is a low-frequency alloantibody. Harr, Robert R. Medical Laboratory Science Review (Page 141). F.A. Davis Company. Kindle Edition.

SITUATION: RhIg is requested on a 28-year-old woman with suspected abortion. When the nurse arrives in the blood bank to pick up the RhIg, she asks the medical laboratory scientist (MLS) if it is a minidose. The MLS replies that it is a full dose, not a minidose. The nurse then requests to take 50 mcg from the 300 mcg syringe to satisfy the physician's orders. What course of action should the MLS take? A. Let the nurse take the syringe of RhIg, so that she may withdraw 50 mcg B. Call a supervisor or pathologist C. Instruct the nurse that the blood bank does not stock minidoses of RhIg and manipulating the full dose will compromise the purity of the product D. Instruct the nurse that the blood bank does not stock minidoses of RhIg, and relay this information to the patient's physician

D Blood banks operate by strict standard operating procedures. These include which products are supplied from the blood bank. While B may also be a solution, D is the best answer because the patient's physician can communicate with the pathologist once he or she receives this information from the nurse. Harr, Robert R. Medical Laboratory Science Review (Page 161). F.A. Davis Company. Kindle Edition.

A sample of amniotic fluid collected for fetal lung maturity studies from a woman with a pregnancy compromised by hemolytic disease of the newborn (HDN) has a creatinine of 88 mg/dL. What is the most likely cause of this result? A. The specimen is contaminated with blood B. Bilirubin has interfered with the measurement of creatinine C. A random error occurred when the absorbance signal was being processed by the analyzer D. The fluid is urine from accidental puncture of the urinary bladder

D Creatinine levels in this range are found only in urine specimens. Adults usually excrete between 1.2 and 1.5 g of creatinine per day. For this reason, creatinine is routinely measured in 24-hour urine samples to determine the completeness of collection. A 24-hour urine with less than 0.8 g/day indicates that some of the urine was probably discarded. Creatinine is also used to evaluate fetal maturity. As gestation progresses, more creatinine is excreted into the amniotic fluid by the fetus. Although a level above 2 mg/dL is not a specific indicator of maturity, a level below 2 mg/dL indicates immaturity. Harr, Robert R. Medical Laboratory Science Review (Page 241). F.A. Davis Company. Kindle Edition.

Parasite stages that are immediately infective for humans on passage from the gastrointestinal tract include: A. Schistosoma spp. eggs B. Toxoplasma gondii bradyzoites C. Giardia lamblia trophozoites D. Cryptosporidium spp. oocysts

D Cryptosporidium spp. oocysts are immediately infectious when passed in the stool, regardless of the stool consistency (formed—liquid). Harr, Robert R. Medical Laboratory Science Review (Page 474). F.A. Davis Company. Kindle Edition.

SITUATION: A sample for ammonia assay is taken from an IV line that had been capped and injected with lithium heparin (called heparin lock). The sample is drawn in a syringe containing lithium heparin, and immediately capped and iced. The plasma is separated and analyzed within 20 minutes of collection, and the result is 50 micrograms/dL higher than one measured 4 hours before. What is the most likely explanation of these results? A. Significantly greater physiological variation is seen with patients having systemic, hepatic, and gastrointestinal diseases B. The syringe was contaminated with ammonia C. One of the samples was collected from the wrong patient D. Stasis of blood in the line caused increased ammonia

D Falsely elevated blood ammonia levels are commonly caused by improper specimen collection. Venous stasis and prolonged storage cause peripheral deamination of amino acids, causing a falsely high ammonia level. Plasma is the sample of choice since ammonia levels increase with storage. Lithium heparin and EDTA are acceptable anticoagulants; the anticoagulant used should be tested to make sure it is free of ammonia. A vacuum tube can be used if filled completely. Serum may be used provided the tube is iced immediately, and the serum is separated as soon as the sample clots. The patient should be fasting and must not have smoked for 8 hours because tobacco smoke can double the plasma ammonia level. Harr, Robert R. Medical Laboratory Science Review (Page 244). F.A. Davis Company. Kindle Edition.

What effect does hematocrit have on POC tests for whole-blood glucose monitoring? A. Low hematocrit decreases glucose readings on all devices B. High hematocrit raises glucose readings on all devices C. The effect is variable and dependent on the enzyme/coenzyme system D. Low hematocrit raises readings and high hematocrit lowers readings unless corrected

D Hematocrit affects POCT glucose measurements. High hematocrit lowers the glucose because RBC glucose concentration is lower than plasma concentration. Other factors include binding of oxygen to hemoglobin and the slower diffusion of glucose onto the solid phase—both of which occur when the hematocrit is high. Bias due to an abnormal hematocrit can be avoided by simultaneously measuring the conductivity of the sample. The hematocrit is calculated and used to mathematically correct the glucose measurement. Harr, Robert R. Medical Laboratory Science Review (Page 212). F.A. Davis Company. Kindle Edition.

In which case might a very low plasma TSH result not correlate with thyroid status? A. Euthyroid sick syndrome B. Congenital hypothyroidism C. When TBG is elevated D. After high-dose corticosteroid treatment

D In persons with severe chronic diseases or who have hCG-secreting tumors, TSH production may be suppressed. Some drugs, especially high doses of corticosteroids, will suppress TSH production. Low TSH levels not matching thyroid status can also be seen in patients who have recently been treated for hyperthyroidism because there is a delay in the pituitary response. High-sensitivity TSH assays that can measure as little as 0.01 mIU/L and free T 4 and T 3 can help differentiate these conditions from clinical hyperthyroidism. If the TSH is below .03 mIU/L and the free hormone levels are increased, this points to hyperthyroidism. Lab values in euthyroid sick syndrome may mimic mild hypothyroidism. In euthyroid sick syndrome, thyroid function will be normal, but TSH may be slightly increased owing to lower levels of free T 3 . In euthyroid sick syndrome, the rT 3 will be increased. Harr, Robert R. Medical Laboratory Science Review (Page 293). F.A. Davis Company. Kindle Edition.

If the peak level is appropriate but the trough level too low at steady state, then the dose interval should: A. Be lengthened without changing the dose per day B. Be lengthened and dose rate decreased C. Not be changed, but dose per day increased D. Be shortened, but dose per day not changed

D Increasing the dose rate may result in peak drug levels in the toxic range. Decreasing the dosing interval will raise the trough level so that it is maintained in the therapeutic range. The trough level is affected by the drug clearance rate. If clearance increases, then trough level decreases. Harr, Robert R. Medical Laboratory Science Review (Page 296). F.A. Davis Company. Kindle Edition.

A 65-year-old woman was admitted to the hospital with acute respiratory distress, fever, myalgia, and headache. Influenza A or B was suspected after ruling out bacterial pneumonia. Which of the following methods could be used to confirm influenza infection? A. Influenza virus culture in Madin-Darby canine kidney B. Hemagglutination-inhibition test for antibodies in the patient's serum C. Direct examination of nasal epithelium for virus using fluorescent antibody stain D. All of these options

D Influenza virus types A, B, and C may be grown and isolated in embryonated hen eggs or cell cultures using Madin-Darby canine kidney (MDCK), rhesus monkey, or cynomolgus monkey kidney cells. Cell culture using MDCK cells is the most rapid technique, permitting identification within 1-3 days. The hemagglutination inhibition test can be used to titer antibody to influenza virus and to distinguish virus subtypes, if specific antiserum is available. Direct fluorescent and enzyme immunoassays using monoclonal antibodies to nucleoprotein antigens in infected nasal epithelium are used for rapid diagnosis of both influenza A and influenza B infections. Harr, Robert R. Medical Laboratory Science Review (Page 458). F.A. Davis Company. Kindle Edition.

Culture on MTM media of a vaginal swab produced several colonies of gram-negative diplococci that were catalase and oxidase positive and Superoxol negative. Given the following carbohydrate reactions, select the most likely identification. Glucose = + Sucrose = Neg Lactose = + Maltose = + Fructose = Neg A. Neisseria gonorrhoeae B. Neisseria sicca C. Neisseria flavescens D. Neisseria lactamica

D N. lactamica is part of the normal vaginal and throat flora and is the only Neisseria species that grows on MTM that utilizes lactose. Other saprophytic Neisseria spp. may utilize lactose but do not grow on MTM media. Harr, Robert R. Medical Laboratory Science Review (Page 425). F.A. Davis Company. Kindle Edition.

A patient with a prolonged PT is given intravenous vitamin K. The PT corrects to normal after 24 hours. What clinical condition most likely caused these results? A. Necrotic liver disease B. Factor X deficiency C. Fibrinogen deficiency D. Obstructive jaundice

D Obstructive jaundice contributes to coagulation disorders by preventing vitamin K absorption. Vitamin K is fat soluble and requires bile salts for absorption. Parenteral administration of vitamin K bypasses the bowel; hence the need for bile salts. Harr, Robert R. Medical Laboratory Science Review (Page 53). F.A. Davis Company. Kindle Edition.

An immunocompromised patient continues to have diarrhea after repeated ova and parasites (O&P) examinations (sedimentation concentration, trichrome permanent stained smear) were reported as negative; organisms that might be responsible for the diarrhea include: A. Cryptosporidium spp., Giardia lamblia, and Cystoisospora belli B. Giardia lamblia, microsporidia, and Endolimax nana C. Taenia solium and Endolimax nana D. Cryptosporidium spp. and microsporidia

D Routine O&P examinations usually do not allow the detection of Cryptosporidium spp. oocysts and microsporidial spores; special stains are required. Modified acid-fast stains for coccidia and modified trichrome stains for the microsporidial spores are recommended. Harr, Robert R. Medical Laboratory Science Review (Page 474). F.A. Davis Company. Kindle Edition.

A 60-year-old Brazilian patient with cardiac irregularities and congestive heart failure suddenly dies. Examination of the myocardium revealed numerous amastigotes, an indication that the cause of death was most likely: A. Leishmaniasis with Leishmania donovani B. Leishmaniasis with Leishmania braziliense C. Trypanosomiasis with Trypanosoma gambiense D. Trypanosomiasis with Trypanosoma cruzi

D T. cruzi, the cause of Chagas disease, has two forms within the human: the trypomastigote in the blood and the amastigote in the striated muscle (usually cardiac muscle and intestinal tract muscle). Harr, Robert R. Medical Laboratory Science Review (Page 472). F.A. Davis Company. Kindle Edition.

A 92-year-old male diagnosed with anemia and episodes of frequent falling was typed B negative and transfused 1 unit of packed red blood cells, also B negative. He was not recently transfused, and the antibody screen was negative. During the transfusion, his temperature rose from 36.2 degrees Celsius to 36.4, his pulse rose from 96 to 124, respirations from 18 to 20, and BP from 127/81 to 174/83. He was transfused with 205 mL before a reaction was called by the transfusionist. The postspecimen DAT was negative and clerical check acceptable. Urinalysis yielded 1+ blood with 5 RBCs microscopically. Other symptoms included tachycardia and flushing. What reaction had most likely taken place? A. Febrile nonhemolytic B. Acute hemolytic C. Anapylactic D. Volume overload

D The tachycardia, increased pulse, and volume transfused before a reaction was called are consistent with volume overload. The temperature change did not meet criteria for a febrile reaction, and evidence for a hemolytic reaction is lacking. Harr, Robert R. Medical Laboratory Science Review (Page 147). F.A. Davis Company. Kindle Edition.

An autologous unit of whole blood was collected on a 33-year-old woman in preparation for a knee replacement procedure in 3 weeks. The whole blood unit had her hyphenated last name, first name, and last four digits of her social security number for identification. The lab computer system, however, only had her married name and first name, medical record number, and social security number. What should be done with this blood product? A. Discard the unit B. Make the unit available for transfusion C. Confirm the name with donor and have admissions make the correction in the computer system, then make the unit available for transfusion D. Ensure that social security numbers match, confirm the name with donor and have admissions make the correction in the computer system with the medical director's approval, then make the unit available for transfusion

D This is a common scenario with women who have recently married, and have not changed their license or other form of identification given to the collection facility. Checking that other demographic information matches is sufficient if approved by the medical director, because an autologous unit is very difficult to replace in time for surgery. Harr, Robert R. Medical Laboratory Science Review (Page 157). F.A. Davis Company. Kindle Edition.

A patient treated for a germ cell tumor has a total and free β-hCG assay performed prior to surgery. The result is 40,000 mIU/mL. One week following surgery, the hCG is 5,000 mIU/mL. Chemotherapy is started, and the hCG is measured 1 week later and found to be 10,000 mIU/mL. What does this indicate? A. Recurrence of the tumor B. Falsely increased hCG owing to drug interference with the assay C. Analytical error with the test reported as 5,000 mIU/mL D. Transient hCG increase caused by chemotherapy

D Treatment of tumors with chemotherapy often causes a transient increase in the production of tumor markers as the drugs destroy tumor cells. The half-life of hCG is 24-36 hours; therefore, the expected decline 1 week postsurgery was consistent with the result of 5,000 mIU/mL. Initiation of chemotherapy probably caused the hCG to double in the following week. The hCG assay should be monitored at regular intervals for several months, since a failure for it to decline or an increased level would suggest recurrence. Harr, Robert R. Medical Laboratory Science Review (Page 307). F.A. Davis Company. Kindle Edition.

Four blood cultures were taken over a 24-hour period from a 20-year-old woman with severe diarrhea. The cultures grew motile (room temperature), gram-negative rods. A urine specimen obtained by catheterization also showed gram-negative rods, 100,000 col/mL. Given the following results, which is the most likely organism? TSI = A/A gas Indole = + VP = Neg = + H2 S = Neg Citrate = Neg Urease = Neg Lysine decarboxylase = + Phenylalanine deaminase = Neg A. Proteus vulgaris B. Salmonella typhi C. Yersinia enterocolitica D. E. coli

D Typically, the IMViC reactions for the organisms listed are: E. coli (++00) S. typhi (0+00) Y. enterocolitica (V+00) P. vulgaris (++00) Note: Indole reaction is variable (V) for Y. enterocolitica. Harr, Robert R. Medical Laboratory Science Review (Page 397). F.A. Davis Company. Kindle Edition.

A hemoglobin F concentration of 100% may be seen in which beta thalassemia? Beta thalassemia minor (β0/β) Beta thalassemia major (β0/β0) Delta-beta thalassemia minor (δβ0/β) Delta-beta thalassemia major (δβ0/δβ0)

Delta-beta thalassemia major (δβ0/δβ0) Delta-beta thalassemia major (δβ0/δβ0) exists when both gene loci for beta and delta chains are completely deleted or inactive on both chromosomes. Patients with this condition are unable to produce δ chains or β chains. Consequently, these patients can only produce hemoglobin F (α2γ2). Patients with beta thalassemia minor (β0/β) have only one functional copy of the β-globin gene. These patients typically present with an asymptomatic microcytic and hypochromic anemia. Since there is a decrease in β chain production, hemoglobin A (α2β2) is decreased while hemoglobin A2 (α2δ2) is increased. There may be a slight increase in hemoglobin F (α2γ2) production. Patients with beta thalassemia major (β0/β0) are unable to produce β chains. Therefore, they will have an increased production of hemoglobin F (α2γ2) in addition to a variable production of hemoglobin A2 (α2δ2). Patients with delta-beta thalassemia minor (δβ0/β) have only one functional copy of their β-globin and δ-globin genes. Due to the loss of these genes, they will have decreased concentrations of hemoglobin A (α2β2) and hemoglobin A2 (α2δ2). They will have an increased production of hemoglobin F (α2γ2) to about 5%-20% of total hemoglobin production. Question Difficulty: Level 7

Review the descriptions of molecular testing techniques and select the correct statements. (Choose all that apply) Renaturation is the process of converting double-stranded DNA to single strands Denaturation is the process of converting double-stranded DNA to single-stranded DNA Target amplification assays use methods to make more copies of a specific region of DNA In signal amplification methods, the target number increases as the signal is amplified

Denaturation is the process of converting double-stranded DNA to single-stranded DNA Target amplification assays use methods to make more copies of a specific region of DNA Denaturation uses processes that make double-stranded DNA single-stranded. Target amplification methods increase copies of target nucleic acid strands. In other amplification methods, target number is not changed; signal or probes are amplified. Question Difficulty: Level 8

Polymerase chain reaction (PCR) copies DNA through repeated cycles of three basic steps. What is the correct order of these steps? Extraction, annealing, denaturation Denaturation, annealing, extraction Denaturation, extension, annealing Denaturation, annealing, extension

Denaturation, annealing, extension The correct answer is denaturation, annealing, extension. Extraction of the DNA from the clinical sample occurs before the initiation of PCR. Once extracted, the sample is heated to a temperature at which the strands of DNA separate (denaturation). Next, the temperature is lowered and the primers attach (anneal) to their complementary targets. Lastly, the temperature is raised and new strands of DNA are synthesized (extension), utilizing free nucleotides in the reaction mixture. Question Difficulty: Level 8

If a pipette is labeled (TC) "to contain" you would do the following: Drain pipette, but not blow out Drain contents then rinse out with diluting fluid Drain to last mark on pipette Do not consider the meniscus when filling

Drain contents then rinse out with diluting fluid "TC" means the total volume contained in the pipette. These pipettes are calibrated to contain a specific volume, but are not calibrated to deliver that specific amount. In order to ensure that the entire volume of fluid has been emptied, you must rinse the pipette with a diluting fluid to remove total contents. "TD" means to deliver the amount of fluid indicated on the pipette. These pipettes, when held vertically, will deliver the specific fluid amount with the help of gravity. There is no rinsing or blowing out required. "Blowout" pipettes are a category of pipettes that are calibrated similarly to the TD pipettes. The difference is that the last drop left in the pipette has to be blown out after the fluid drained out by gravity. A "blowout" pipette has an etched ring near the suction opening. Draining the fluid to a specific mark or to the last mark on the pipette is done on a "graduated" or "measuring" pipette. The meniscus should always be considered when filling out a pipette. When measuring clear fluids, the bottom of the meniscus is read, while for colored or viscous solutions the top of the meniscus is read. Question Difficulty: Level 7

Examples of media containing ePHI (electronic protected health information) include: Electronic medical records on the hospital server hard drive. Anonymous patient participation in a stress level study. De-identified heart rate readings. A research report on a jump drive containing charts of average patient blood pressure readings over time, without patient names or other specific patient information.

Electronic medical records on the hospital server hard drive. HIPAA rules apply to any health information that can be linked to a person by name, social security number, employee number, hospital identification number, or other identifier. These provisions cover protected health information, regardless of whether it is or has been in electronic form or relates to any past, present, or future health care or payments. The research report contains only de-identified health information, and thus is no longer protected ePHI. Question Difficulty: Level 7

Which of the following microorganisms is LEAST likely to produce a capsule or slime layer? Escherichia coli Klebsiella pneumoniae Streptococcus pneumoniae Pseudomonas aeruginosa

Escherichia coli Escherichia coli is the correct answer because out of all the organisms listed, this organism is least likely to produce a capsule or slime layer. Klebsiella pneumonia is incorrect because this organism is an encapsulated gram-negative organism that produces highly mucoid colonies on agar. Klebsiella pneumoniae is also a non-motile, lactose fermenting, facultative anaerobe which is found in the normal flora of the mouth, skin, and intestines. Streptococcus pneumoniae is incorrect because this organism has the potential to produce a capsule or slime layer that appears mucoid on agar. The mucoid colonies can resemble green water droplets due to its alpha hemolytic property. Streptococcus pneumoniae is both normal commensal flora and a pathogen of the respiratory tract. Pseudomonas aeruginosa is incorrect because this organism is known to produce a capsule or slime layer. The mucoid colonies are produced due to alginate slime. The presence of slime prevents phagocytosis by white cells and helps the organism cause disease. Question Difficulty: Level 7

Anti-Fyb & Anti-Lea Anti-Fyb and anti-Lea are the correct answers. Judging by the difference in reactions at different phases, it is very likely that more than one antibody is present. Since some reactions are only present during IS and others only show up during 37o and AHG, there may be a warm and cold antibody present together. Other antibodies such as anti-C, for example, may not be ruled out; however, the pattern of reactivity does not match which leaves us with anti-Fyb and anti-Lea. It cannot be anti-M because cells 6 & 8 did not show reactions. It cannot be anti-k because all of the cells did not show reactions. It cannot be anti-D since cell 5 did not show a reaction. Question Difficulty: Level 8

Evaluate the panel shown on the right. Which antibody(ies) is/are most likely causing this reaction? Note: Use the reaction patterns to identify the most likely antibody(ies). There may be additional antibodies present that cannot be ruled out. Anti-M Anti-k Anti-D Anti-Fyb & Anti-Lea

Streptococcus pneumoniae Streptococcus pneumoniae are gram-positive cocci occurring in pairs that are often lancet-shaped (i.e.- pointed end), also known as "cats eyes". Neisseria species are gram-negative bacteria sometimes described as kidney bean- or coffee bean-shaped diplococci. They have flattened sides that are adjacent to each other. Streptococci other than Streptococcus pneumoniae are gram-positive cocci that are typically arranged in chains, but can also appear in pairs without the lancet morphology. Staphylococci are gram-positive cocci that are arranged singly and in clusters. Question Difficulty: Level 5

Examine the gram stain illustration. The organism labeled "A" is most likely which of the following? Neisseria spp. Streptococcus pyogenes Staphylococcus aureus Streptococcus pneumoniae

Hemoglobin electrophoresis for the presence of Hb S The presence of both sickled cells and target cells in this blood smear is suggestive of sickle cell anemia. However, hemoglobin electrophoresis is necessary to establish the underlying condition. Aside from homozygous HbSS, a double heterozygous condition known as Hemoglobin SC disease also exists where one beta chain carries the mutation for HbS and the other beta chain carries the mutation for HbC. In addition, HbS can be present with thalassemia. Sickle cell anemia can also demonstrate hereditary persistence of fetal hemoglobin (HbS/HPFH). Other rare HbS combinations are also possible and need to be determined through hemoglobin electrophoresis or other appropriate methods. Serum vitamin B12 and foliate levels are assayed to follow up on megaloblastic anemia. Sickled cells or target cells are not found. Hb Bart's on an electrophoresis (γ-globin tetramer) is seen in alpha thalassemia major. Target cells are seen on smears but not sickled cells. HbA2 is elevated in beta thalassemia. Target cells are seen, but not sickled cells. Question Difficulty: Level 7

Examine the red cells shown in this image. Which of the following tests are necessary to confirm the condition suggested by the morphology? Serum vitamin B12 and folate assay Hemoglobin electrophoresis for the presence of Hb S Hemoglobin electrophoresis for the presence of Hb Bart's Column chromatography for elevated Hb A2

Parvovirus B19 is the only human pathogen in the family Parvoviridae. It is most known for its association with which of the following diseases? Hepatitis Kaposi sarcoma Fifth disease Measles

Fifth disease Parvovirus B19 is the known causative agent of Fifth disease, so named because it is the fifth of the childhood exanthems. Replication of the virus is largely restricted to erythroid progenitor cells, bone marrow, and fetal liver cells. Generally, fifth disease only demonstrates a characteristic facial rash; however, in patients with anemia, infection with parvovirus B19 may lead to severe outcomes. Hepatitis is caused by hepatitis B virus (HBV) of the family Hepadnaviridae. This virus has long been known to be the cause of significant liver damage associated with morbidity and mortality. Despite the creation of a successful vaccine, an estimated 50 million new cases of hepatitis are seen annually worldwide. Kaposi sarcoma, a tumor of the connective tissue, is caused by human herpes virus 8 (HHV-8). It is a member of the family Herpesviridae, along with other viruses such as herpes simplex virus types 1 and 2 (HSV-1, HSV-2), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), and cytomegalovirus (CMV). The measles virus, causative agent of measles, is a member of the Paramixoviridae family along with the mumps virus, respiratory syncytial virus (RSV), and metapneumovirus. The measles virus is spread through contact with respiratory secretions of infected individuals. Despite an effective vaccine and regular childhood vaccination in most populations, outbreaks of measles continue to be seen. Question Difficulty: Level 7

For which of these conditions or procedures there may be an increased number of megakaryocytes in the bone marrow, but a decreased number of circulating platelets? Folic acid deficiency Aplastic anemia Radiation Therapy Wiskott-Aldrich syndrome

Folic acid deficiency Pancytopenia is often seen with megaloblastic anemias that are caused by folic acid or vitamin B12 deficiency. Thrombopoiesis (as well as erythropoiesis and granulopoiesis) is ineffective. The bone marrow will contain normal, or even increased megakaryocytes, but the number of platelets entering the peripheral circulation is decreased. In aplastic anemia, megakaryocytes are decreased in number in the bone marrow, leading to a decreased number of circulating platelets. Radiation therapy causes bone marrow hypoplasia. Platelets as well as all other cell lines are depressed. The effect is transient; once the therapy has ended, the marrow will regenerate. In Wiskott-Aldrich syndrome, platelets are very small and thrombocytopenia is present. Question Difficulty: Level 8

Which of the following genotypes are known to be resistant to P. vivax (malaria) merozoites? Fy(a+b+) Fy(a-b-) Jk(a-b-) Jk(a+b+)

Fy(a-b-) The correct answer is Fy(a-b-). In the mid 70s, it was observed that Duffy (Fy) (a-b-) RBC's resist infection by Plasmodium knowlesi and Plasmodium vivax. This provides an explanation for the high frequency of Fy(a-b-) persons originating from West Africa. All of the other genotypes (Fy(a+b+), Jk(a-b-), and Jk(a+b+)) are not known to cause this type of resistance. Question Difficulty: Level 9

Leuconostoc species are streptococcus-like bacteria used in the dairy and pickling industries that have recently caused opportunistic infections in humans. The need to make the laboratory identification is compounded because these bacteria are intrinsically resistant to vancomycin. Which characteristic is most helpful in separating Leuconostoc species from other streptococcus-like organisms? Gas from glucose in MRS broth Leucine aminopeptidase (LAP) activity Ability to grow in 6.5% NaCl (salt tolerance) Ability to grow at 10° C

Gas from glucose in MRS broth Leuconostoc species may be misidentified as Enterococcus, alpha-hemolytic streptococci, Pediococcus, Lactococcus, or lactobacilli (Facklam R, Elliott JA: Clin Microbiol Rev; 1995 Oct; 8(4):479-95). The detection of gas from glucose in Mann, Rogosa and Sharpe (MRS) broth (available from Difco Laboratories) overlaid with petrolatum is the one characteristics that differentiates Leuconostoc species from the other streptococcal-like organisms. All of the other characteristics listed in this exercise are either variable for Leuconostoc species or are shared by other streptococcal-like organisms and therefore are not discriminatory tests. Question Difficulty: Level 9

Nocardia farcinica has been distinguished from other members of the Nocardia asteroides complex because most strains are resistant to several extended-spectrum antimicrobial agents and other antibiotics commonly used to treat nocardia infections, and are more commonly recovered from patients with severe underlying illness. Each of these characteristics are helpful in the identification of N. farcinica EXCEPT: The ability to grow at 45°C Gelatin hydrolysis A white opacity around colonies on Middlebrook agar Failure to turn arylsulfatase media in two weeks

Gelatin hydrolysis Nocardia farcinica gives a negative reaction for gelatin hydrolysis. Thus, this is the correct response. The other responses are correct identification characteristics for N. farcinica. This species of Nocardia can grow at 45°C. N. farcinica can develop a white opacification around colonies growing on Middlebrook agar. N. farcinica is negative for arylsulfatase media in 14 days, so this response is correct. The turning of arylsulfatase media in two weeks is a distinguishing characteristic for another member of the Nocardia asteroides complex, Nocardia nova. Question Difficulty: Level 8

The presumptive diagnosis of fungal infections may be made based on the location or sites of visit in which they have become endemic. One such condition, is colloquially referred to as "Spelunker's Scourge". This condition occurs after a tour or work in underground caves located in the Midwest, where dust contaminated with bird and bat dung is inhaled. Select the name of the fungus from the choices shown below that causes this endemically-acquired respiratory infection. Coccidioides immitis Histoplasma capsulatum Blastomyces dermatitidis Paracoccidioides brasiliensis

Histoplasma capsulatum Histoplasma capsulatum is the correct response. A high percentage of the native population living in the moist inland river valleys in the Midwest is skin test positive for Histoplasmosis, indicating past infection. These infections are not necessarily associated with visits to local underground caves, but the colloquial "Spelunker's Scourge" applies to infections where case histories reveal an association. Coccidioides immitis infections are endemic in southern California where many natives of the San Joaquin Valley are also skin test positive from past infections. Endemic infections also extend into southern Nevada, Arizona and northern Mexico as well. Travelers to these areas also may develop Coccidioidomycosis, colloquially referred to as "Sonoran Serenade", often in the form of a delayed development of localized lung cysts following the inhalation of spore-contaminated wind-blown sand and dust. Blastomyces dermatitidis endemic infections are localized more in the northern Midwest states, particularly in Wisconsin, associated with boat travel and camping trips along riverways. One such camping excursion, later called the "Namekagon Adventure", involved a group of physicians on a trip along the Namekagon River in Wisconsin, several of whom developed lung infections after splitting old decayed stumps and logs in order to start a fire. Paracoccidioides brasiliensis lung and skin infections are largely endemic in South America, particularly in Brazil. Question Difficulty: Level 9

#1 - lymphocyte; #2 - monocyte #1 is a (large) lymphocyte and #2 is a monocyte. Normal small lymphocytes have scant cytoplasm, but a large lymphocyte has more abundant cytoplasm, which may make it difficult to distinguish from a monocyte on a peripheral blood smear. Monocytes (as seen in cell #2) have abundant blue-gray cytoplasm, often described as having a "ground glass" appearance. Cell #1 is not a monocyte; its clumpy condensed chromatin in the nucleus distinguish it from the looser chromatin seen in a monocyte. Cell #1, though larger than a "small" lymphocyte, does not have the very rounded nucleus and abundant dark blue cytoplasm of a plasma cell. Plasma cells are also not normally seen in peripheral blood smears. Cell #2 could possibly be confused with a reactive lymphocyte, since both can be large with relatively large amount of cytoplasm. However, the looser chromatin and convolutions in the nucleus of this cell, as well as the blue grey cytoplasm with vacuoles distinguish it as a monocyte rather than a reactive lymphocyte. Question Difficulty: Level 1

Identify each of the white blood cells that are shown in this image of a Wright-Giemsa stained peripheral blood smear, 1000x magnification. #1 - monocyte; #2 - monocyte #1 - lymphocyte; #2 - monocyte #1 - plasma cell; #2 - monocyte #1 - lymphocyte; #2 - reactive (atypical) lymphocyte

L, K The course and fine adjustment knobs are labeled with the L and K respectively. Question Difficulty: Level 1

Identify the Coarse adjustment and Fine adjustment L, K A, G F, D J, H

Speckled The speckled pattern occurs in the presence of antibody to any extractable nuclear antigen devoid of DNA or histone. The antibody is detected against the saline extractable nuclear antigens, anti-RNPand anti-Sm. A grainy pattern with numerous round dots of nuclear fluorescence, without staining of the nucleoli, is seen in this pattern type. Antibodies to anti-RNP has been found in patients with a wide variety of rheumatic disorders, including SLE. Antibodies to Sm antigen have been shown to be highly specific for patients with systemic lupus erythematosus (SLE). This is an example of a cell cycle dependent speckled ANA pattern called anti-proliferating cell nuclear antigen (PCNA). With this pattern the antigen that the antibodies are directed against is only expressed during a limited portion of the cell's growth cycle. During other parts of the growth cycle the antigen is not expressed. This creates a pattern where only 30-50% of the cells stain positive. The speckled staining within these positive cells varies between coarse speckled (a) and smooth speckled (b). Cells not expressing the antigen are negative (c). A homogeneous pattern characterizes anti-DNA nucleoprotein antibodies (i.e. antibodies to nDNA, dsDNA, ssDNA, DNP or histones). The antinuclear antibody (ANA) test pattern is characterized by smooth staining in the nuclei of the interphase cells and smooth staining in the chromosomal areas of the metaphase mitotic cells . The nucleoli may or may not stain. Although vacuoles may be seen, the whole nucleus fluoresces evenly. In order for the ANA to be positive there must be a clearly discernible pattern in the nuclei of the interphase cells. Metaphase mitotic cells are used to assist in identification of the ANA pattern. This pattern is typically seen in rheumatoid disorders. High titers of homogeneous ANA suggest Systemic Lupus Erythrematosus (SLE); low titers may be found in SLE, Rheumatoid arthritis, Sjorgen's syndrome, and mixed connective tissue disease. Anticentromere antibody reacts with centromeric chromatin of metaphase and interphase cells. The particular pattern on tissue culture cells is discrete and speckled. This antibody is found infrequently in the serum of patients with systemic lupus erythematosus (SLE). Anti-Ro (SS-A) antibody is included in the nonhistone protein (NhPs) and NhP-RNA complexes in systemic rheumatic disease. The incidence of the antibody is 50% in cases of SLE. Detection of antibodies to SS-A/Ro varies according to the fixation method. Alcohol diminishes or destroys the SS-A/Ro speckled ANA pattern, leading to a negative ANA. Question Difficulty: Level 6

Identify the anti-nuclear antibody (ANA) pattern in this microscopic image. homogeneous Speckled anticentromere antibody Anti-Ro (SS-A) (alcohol fixation)

Homogeneous or Diffused staining pattern; Systemic Lupus Erythematosus The image displays a homogeneous ANA staining pattern. This pattern is characterized by smooth staining in the nucleus of the interphase cells. The nucleoli may or may not stain. Notice the smooth staining in the chromosomal area of the metaphase mitotic cells (b). Note: In order for the ANA test to be positive there must be a clearly discernible pattern in the nucleus of the interphase cells. Metaphase mitotic cells are used to assist in identification of the ANA pattern. (a) points to the nucleus (nuclei) of the interphase cell(s), the primary consideration for discerning the ANA pattern and (b) indicates the metaphase mitotic cells. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in identification of the ANA pattern. Disorders related to a homogeneous ANA staining pattern include Systemic Lupus Erythematosus (SLE), Rheumatoid arthritis, Sjogren's syndrome, or Mixed Connective tissue Disease. The image displays a homogeneous or diffused ANA staining pattern. Although the presented ANA staining pattern displays a homogeneous pattern, this type of pattern is not associated with scleroderma. Scleroderma is associated with a nucleolar staining pattern. The image presented is a homogeneous or diffuse ANA staining pattern not a nucleolar staining pattern. A nucleolar pattern is characterized by smooth staining in the nucleus of the interphase cells (a). The nucleoli may or may not stain. The chromosomal area of the metaphase mitotic cells is negative (b). A nucleolar pattern can be associated with Sjogren's syndrome, scleroderma or SLE. The image presented is a homogeneous or diffuse ANA staining pattern not a peripheral staining pattern. In a peripheral or rim pattern, the central staining protein of the nucleus is only lightly stained or not stained at all but the nuclear margins fluoresce strongly and appear to extend into the cytoplasm. A peripheral pattern is associated with SLE in an active stage or Sjorgen's syndrome. Question Difficulty: Level 5

Identify the antinuclear antibody (ANA) staining pattern in the image (a) and interpret what related disorder can be associated with this pattern? Homogeneous or Diffused staining pattern; Systemic Lupus Erythematosus Homogeneous or Diffused staining pattern; Scleroderma Nucleolar staining pattern; Sjogren's syndrome Peripheral or rim staining pattern; active Systemic Lupus Erythematosus

Eosinophilic Myelocyte The correct answer here is eosinophilic myelocyte. An eosinophilic myelocyte is the third stage or maturation. You can now recognize the lineage the cell is maturing to based on the recognizable appearance of specific cytoplasmic granulation seen in the image with the distinct light pink secondary granules seen in eosinophils. Promyelocyte's are too early in the maturation process to be able to identify the exact lineage of cells it will mature to. This is the second stag of maturation seen in granulocytes. Features include the presence of prominent granulation, primarily azurophilic granules rich in myeloperoxidase and chloroacetate esterase enzymes. Plasma cell is a fully mature B-cell with an eccentric nucleus with a chromatin arranged in a fine pattern. The cytoplasm is nongranular with a mottled blue color. Megakaryocyte's are the largest of white blood cells seen primarily in the bone marrow. These cells do not contain the light pink secondary granules seen in image. Question Difficulty: Level 4

Identify the arrowed cells in the image to the right from the Wright-Giemsa stained blood smear slide. Eosinophilic Myelocyte Promyelocyte Plasma Cell Megakaryocyte

Mesothelial This is a binucleate mesothelial cell. Notice the mononuclear mesothelial cells also present in this slide. The binucleate mesothelial cell retains the morphologic features of the mononuclear mesothelial cells surrounding it, which helps in its identification. Macrophages, a mononuclear (monocyte) cell found in tissues, may contain ingested material and vacuoles in the cytoplasm and are part of the immune system. Tumor cells are usually large with high nucleus-to-cytoplasm ratio, and often occur in clumps. Histiocytes are macrophages (mononuclear) that have ingested materials such as RBCs. Question Difficulty: Level 5

Identify the bi-nucleate cell (see arrow) in the pericardial fluid sample shown here. Macrophage Tumor cell Histiocyte Mesothelial

Lymphocyte This cell is a lymphocyte. Lymphocytes are generally the smallest normal WBC seen in the peripheral blood. Metamyelocytes are the stage of myelocytes that occur before the band stage. The nuclear shape is slightly indented, with a slightly larger size of 10 to 18 um. The nuclear color is light blue-purple with basophilic chromatin. Nucleoli are absent. Cytoplasm has the specific granules. Segmented neutrophils (polymorphonuclear leukocytes, or segs) are the mature phagocytes that migrate through tissues to destroy microbes and respond to inflammatory stimuli. Segmented neutrophils comprise 40-75% of the peripheral leukocytes. They are usually 9 to 16 µm in diameter. The nuclear lobes, normally numbering from 2 to 5, may be spread out so that the connecting filaments are clearly visible, or the lobes may overlap or twist. The chromatin pattern is coarse and clumped. The cytoplasm is abundant with a few nonspecific granules and a full complement of rose-violet specific granules. Monocytes are large cells (12-18um) with a folded nuclear shape. The nucleus has a fine reticular pattern and the cytoplasm is pale gray/blue with numerous fine granules throughout. Cytoplasmic vacuoles may be present. Question Difficulty: Level 2

Identify the cell in this illustration indicated by the arrow: Metamyelocyte Segmented neutrophil Lymphocyte Monocyte

Myelocyte The cell shown in this image is a myelocyte. Myelocytes typically have an eccentric nucleus with cytoplasm similar to a mature neutrophil with a slightly bluer tint due to the cell's immaturity. Myelocytes have both primary and secondary granules present in the cytoplasm. The nucleus is less mature and therefore has a loose chromatin clumping pattern. The nucleus of a monocyte is typically horseshoe shaped and has numerous folds. Its cytoplasm can be described as having a crushed glass appearance. Metamyelocytes have a similar appearance to the myelocyte. They main difference is that nucleus has begun to indent. The nucleus of the metamyelocyte is described as kidney-bean shaped. As a general rule, lymphocytes lack cytoplasmic granules. The nucleus of a lymphocyte has a dense chromatin pattern, therefore retains more stain and appears darker than the other cells listed as answer options. Question Difficulty: Level 5

Identify the cell in this illustration indicated by the arrow: Myelocyte Monocyte Metamyelocyte Lymphocyte

Monocyte The cell in the image is a monocyte. Monocytes typically have a convoluted nuclear shape with plenty of light blue cytoplasm. Vacuoles are often common findings in monocytes, similar to what is depicted in this image. Prolymphocytes have a large nucleus with a large nucleus to cytoplasmic ratio (N:C ratio). The nucleus is round or ovoid and centrally located within the cell. Myeloblasts have a large nucleus with a large N:C ratio and have nucleoli present within the nucleus. Large lymphocytes also have a round to ovoid nucleus with abundant cytoplasm. The nucleus stains darker due to a dense nuclear chromatin. Question Difficulty: Level 3

Identify the cell in this illustration indicated by the arrow: Prolymphocyte Myeloblast Large lymphocyte Monocyte

Myeloblast The cell indicated in the image is a myeloblast. The nucleus is round to oval with multiple nucleoli and fine chromatin. The cytoplasm is basophilic and occasional granules may be seen. There is a large nucleus to cytoplasmic ratio (N:C). A metamyelocyte has an indented nucleus (<50%), clumpy chromatin, and the cytoplasm contains predominately secondary granules. A myelocyte has a round to oval nucleus, coarse chromatin, and secondary granules become more predominant in the cytoplasm. Promyelocytes contain a round to oval nucleus, one or more nucleoli, and fine chromatin. The cytoplasm is basophilic but distinct primary granules are seen within the cytoplasm at this stage. Question Difficulty: Level 8

Identify the cell indicated in this Wright-Giemsa stained bone marrow. Metamyelocyte Myelocyte Myeloblast Promyelocyte

Polychromatophilic erythrocytes Polychromatophilic RBCs, also known as reticulocytes, have a blue-gray appearance when compared to the other RBCs in the field. They are often larger in size than mature RBCs and either lack central pallor or have diminished central pallor. Spherocytes, on the other hand, appear smaller than a mature RBC due to the fact that their biconcave disc shape has become spherical. Giant platelets have a very granular appearance and are more unevenly shaped. These are not artifacts as they clearly have consistent shape and intact membranes. Question Difficulty: Level 1

Identify the cells at the arrows. Spherocytes Giant platelets Polychromatophilic erythrocytes Artifacts

Cabot ring Cabot rings may be found in RBCs in megaloblastic anemias, thalassemia, and following splenectomy. They appear as ring shaped, loop shaped, or figure eight shaped structures. They were thought to be remnants of microtubules from the mitotic spindle, but recent research indicates that they could be nuclear remnants due to abnormal histone biosynthesis. Auer rods are red rod shaped structures seen in myeloblasts; they are characteristically seen in Acute Myeloid Leukemia (AML). Döhle bodies are dark-staining granules seen in neutrophils, and are associated with infections. Heinz bodies are inclusions of precipitated, denatured hemoglobin, and can be seen in G6PD deficiency, hemolytic anemias, and some hemoglobinopathies. Question Difficulty: Level 1

Identify the inclusion indicated by the arrow: Auer rod Döhle bodies Heinz bodies Cabot ring

Promyelocyte The leukocyte in the image is a promyelocyte. The characteristics that distinguish it as a promyelocyte are: Size: 15-21 micrometers Nucleus: Round to oval shape, delicate chromatin, and nucleoli present Cytoplasm: Blue (basophilic) with many coarse, nonspecific azurophilic granules Nuclear / cytoplasmic (N/C) ratio is approximately 5: 1. The myeloblast is the first recognizable precursor on a peripheral bod smear. The size (14-20 micrometers) with a high nuclear cytoplasm (N: C) ration, and has a usually agranular cytoplasm (deep blue to lighter). Reactive lymphocyte may exhibit a variety of morphologic features but the (N: C) ratio is decreased, the nuclear is usually elongated, and the cytoplasm is basophilic (bluish), and does rarely contains granules (azurophilic). The metamyelocyte is smaller (10-18 micrometers) and the nuclear indentation is present ("kidney bean" shape). The cytoplasm has secondary and tertiary granules and most importantly its color resembles the cytoplasm of a fully mature neutrophil. Question Difficulty: Level 6

Identify the leukocyte seen in this illustration: Myeloblast Promyelocyte Reactive lymphocyte Metamyelocyte

Yeast Yeast is present on this slide. Several examples are indicated by the arrows.Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. WBCs have a rough appearance and contain granules and multilobed nuclei which fill out the cytoplasm of the cell. Squamous epithelial cells are the largest cells found in the urine sediment and can even be seen under low-power field. They may appear as clumps of cells and have a very large irregular-shaped cytoplasm with a prominent centrally located nucleus. Question Difficulty: Level 1

Identify the majority of cells present in this slide. Red blood cells White blood cells (WBCs) Yeast Squamous epithelial cells

Band neutrophil This is a band neutrophil. The nuclear chromatin is clumped. The nucleus is deeply indented (U-shaped), but is not constricted to the point of a filament. Neutrophils are the most numerous granulocytic white blood cells. The neutrophils' cytoplasm stains pink, and contains bluish/lavender granules. The nucleus of a segmented neutrophil normally contains 2-5 lobes that are connected by thin filaments of chromatin. Lymphocytes are non-granular (i.e., no specific granules) white cells with a large dark staining nucleus and very little cytoplasm which stains light blue. They are the smallest white cells by size and typically second most numerous after neutrophils. Monocytes are non-granular (i.e., no specific granules) and the largest white blood cell by size. They have a folded nucleus and an irregular cellular shape. The cytoplasm stains gray-blue and often contains vacuoles. Question Difficulty: Level 1

Identify the nucleated blood cell in the image. Lymphocyte Segmented neutrophil Band neutrophil Monocyte

Lymphocyte Lymphocytes are nongranular white cells with a large dark staining nucleus and very little cytoplasm which stains light blue. They are the smallest white cells by size and typically second most numerous after neutrophils. Neutrophils are the most numerous granulocytic white blood cells. The neutrophils' cytoplasm stains pink, with bluish/lavender granules, and they have multilobulated nuclei which stains dark blue/purple. Basophils are the least numerous granulocytic white blood cells. They can be identified by their large dark blue/purple staining granules and a S shaped nucleus. Monocytes are nongranular and the largest white blood cell by size. They have a folded nucleus and an irregular cellular shape. The cytoplasm stains gray-blue and often contains vacuoles. Question Difficulty: Level 1

Identify the nucleated blood cell that is indicated by the arrow: Lymphocyte Neutrophil Basophil Monocyte

Lymphocyte Lymphocytes are nongranular white cells with a large dark staining nucleus and very little cytoplasm which stains light blue. They are the smallest white cells by size and typically second most numerous after neutrophils. Neutrophils are the most numerous granulocytic white blood cells. The cytoplasm stains pink/lavender due to its granules, and has a multilobulated nuclei which stains dark blue/purple. Basophils are the least numerous granulocytic white blood cells. They can be identified by their large dark blue/black staining granules. Monocytes are nongranular and the largest white blood cell by size. They have a folded nucleus and an irregular cellular shape. The cytoplasm stains gray-blue and often contains vacuoles. Question Difficulty: Level 1

Identify the nucleated blood cell: Lymphocyte Neutrophil Basophil Monocyte

Eosinophil The correct answer is eosinophil. Eosinophils are granulocytic white blood cells which are identified by their large orange/red granules and a dark purple nucleus usually segmented into two lobes. Small lymphocytes are nongranular white cells with a large dark staining nucleus and very little cytoplasm which stains light blue. They are the smallest white cells by size and typically second most numerous after neutrophils. Large lymphocytes are larger than small lymphocytes with an increased amount of blue cytoplasm that may contain some azurophilic granules. Neutrophils are the most numerous granulocytic white blood cells. The neutrophils' cytoplasm stains pink, with bluish/lavender granules, and they have multilobulated nuclei which stains dark blue/purple. Monocytes are nongranular and the largest white blood cell by size. They have a folded nucleus and an irregular cellular shape. The cytoplasm stains gray-blue and often contains vacuoles. Question Difficulty: Level 1

Identify the nucleated blood cell: Lymphocyte Neutrophil Eosinophil Monocyte

Eosinophil Eosinophils are granulocytic white blood cells which are identified by their large orange/red granules and a dark purple nucleus usually segmented into two lobes. Lymphocytes are non-granular white cells with a large dark staining nucleus and very little cytoplasm which stains light blue. They are the smallest white cells by size and typically second most numerous after neutrophils. Neutrophils are the most numerous granulocytic white blood cells. The neutrophils' cytoplasm stains pink, with bluish/lavender granules, and they have multi-lobulated nuclei which stains dark blue/purple. Basophils are the least numerous granulocytic white blood cells. They can be identified by their large dark blue/purple staining granules and a S-shaped nucleus. Question Difficulty: Level 1

Identify the nucleated blood cell: Lymphocyte Neutrophil Eosinophil Basophil

Neutrophil Neutrophils are the most numerous granulocytic white blood cells. The neutrophils' cytoplasm stains pink, with bluish/lavender granules, and they have multilobulated nuclei which stains dark blue/purple. Basophils are the least numerous granulocytic white blood cells. They can be identified by their large dark blue/purple staining granules and a S shaped nucleus. Eosinophils are granulocytic white blood cells which are identified by their large orange/red granules and a dark purple nucleus usually segmented into two lobes. Monocytes are nongranular and the largest white blood cell by size. They have a folded nucleus and an irregular cellular shape. The cytoplasm stains gray-blue and often contains vacuoles. Question Difficulty: Level 1

Identify the nucleated blood cell: Neutrophil Basophil Eosinophil Monocyte

Eosinophil This is an eosinophil that has been disrupted by the mechanical process of making the blood smear. Eosinophils are granulocytic white blood cells which are identified by their large orange/red granules and a dark purple nucleus usually segmented into two lobes. With few exceptions, a mechanically disrupted cell such as this one would not be reported as part of a WBC differential. Neutrophils are the most numerous granulocytic white blood cells. The neutrophils' cytoplasm stains pink, with bluish/lavender granules, and they have multilobulated nuclei which stains dark blue/purple. Monocytes are nongranular and the largest white blood cell by size. They have a folded nucleus and an irregular cellular shape. The cytoplasm stains gray-blue and often contains vacuoles. Lymphocytes are nongranular white cells with a large dark staining nucleus and very little cytoplasm which stains light blue. They are the smallest white cells by size and typically second most numerous after neutrophils. Question Difficulty: Level 1

Identify the nucleated blood cell: Neutrophil Monocyte Eosinophil Lymphocyte

Monocyte The correct answer is monocyte. Monocytes typically have a loose/lacy chromatin pattern in the nucleus with plenty of pale blue cytoplasm. Neutrophils typically have a segmented nucleus with clumped chromatin and many pink to purple granules in their cytoplasm. Lymphocytes are typically the smallest of the normal white blood cells observed in a peripheral smear with a nucleus about the size of a red blood cell and deeply condensed chromatin. Basophils typically have a segmented nucleus with many large purple granules that generally obscure the cytoplasm and nucleus. Question Difficulty: Level 3

Identify the nucleated cell in the image. Neutrophil Monocyte Lymphocyte Basophil

Orthochromic normoblast The nucleated cell in the image is an immature erythrocyte, an orthochromic normoblast. An orthochromic normoblast contains a round nucleus, no nucleoli, condensed chromatin, and a pink cytoplasm. A reticulocyte does not contain a nucleus and the cytoplasm has a slight blue tinge. A lymphocyte is a type of WBC that has a round to oval nucleus, condensed chromatin, and scant blue cytoplasm. A basophilic normoblast has a round to oval nucleus, may contain nucleoli, condensed chromatin, and a dark blue cytoplasm. Question Difficulty: Level 8

Identify the nucleated cell in the image. Reticulocyte Lymphocyte Basophilic normoblast Orthochromic normoblast

Nucleated red blood cells (NRBCs) The correct answer is NRBCs. The predominant nucleated cell in this image is NRBCs. There are neutrophils and metamyelocytes present in this image, but they are not predominant. There are no tumor cells present in this image. Question Difficulty: Level 6

Identify the predominant nucleated cell this cerebrospinal fluid cytospin differential. Nucleated red blood cells (NRBCs) Neutrophils Metamyelocyte Tumor cells

Blastomyces dermatitidis The yeast form of Blastomyces dermatitidis is a thick-walled yeast cell, measuring 8-15 µm in diameter, that characteristically produces a single bud attached by a broad base. Paracoccidioides brasiliensis produces large yeast cells, approximately 15-30 µm in diameter, with multiple buds attached by narrow necks, giving the appearance of a "mariner's wheel." The yeast forms of Sporothrix schenckii are elongated cells that have been called "cigar bodies." Coccidioides immitis does not produce a yeast form in laboratory culture; rather, is identified in stained tissue sections by the production of varying sized spherules, ranging from 30-60 µm in diameter at maturity. The larger, more mature spherules may contain spherical endospores, making identification from direct examination difficult, as Coccidioides species may resemble other dimorphic fungi. Question Difficulty: Level 3

Identify the species of dimorphic fungi in its yeast form as observed under the microscope in this image. Blastomyces dermatitidis Paracoccidioides brasiliensis Sporothrix schenckii Coccidioides immitis

Hyaline cast Hyaline casts generally appear as colorless, homogeneous, and transparent with rounded ends. They can also be seen as a result of dehydration, after diuretic therapy, in renal disease, and transiently as a result of exercise. A mucus thread can be seen under phase-contrast or interference contrast microscopy and can resemble delicate ribbon strands that are generally transparent. They are normal in small numbers in the urine. A cylindroid resembles a cast, with the exception that one end tapers out. They are considered to have the same significance as casts. Waxy casts are yellow, gray, or colorless with and very refractive. They resemble short broad casts with broken ends and cracked edges. Question Difficulty: Level 3

Identify the urine sediment element indicated by the arrow in the illustration: Mucus thread Cylindroid Hyaline cast Waxy cast

Granular cast Fatty casts contain refractile oval fat bodies or free fat droplets. They are derived from renal tubular cells, and may be seen in nephrotic syndrome. Confirmation of fatty casts is done with the help of polarized microscopy (cholesterol forms Maltese crosses) and Sudan III and Oil Red O fat stains (neutral fats and triglycerides stain orange). Question Difficulty: Level 5

Identify the urine sediment element: WBC cast Fatty cast Waxy cast Granular cast

Triple phosphate crystals Triple phosphate crystals appear as colorless prisms with 3 to 6 sides and oblique ends, or as "feathery sleeves". The have been described as "coffin lid shaped", and can occur normally in alkaline urine. They may indicate the presence of an infection. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Amorphous urate crystals are found in acid urine and resemble brick color or yellow/brown dust under the microscope. Ammonium biurate crystals appear as yellow to brown spherical bodies with long irregular spicules, known as "thorn apples". They can occasionally be identified in the alkaline urine of healthy patients, but can also be associated with specimens which are old or not stored properly. Question Difficulty: Level 1

Identify the urine sediment elements indicated by the arrow in the illustration: Cholesterol crystals Triple phosphate crystals Amorphous urate crystals Ammonium biurate crystals

Cholesterol crystals Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Uric acid crystals appear in acid urine and resemble yellow-brown four-sided flat planes, rosettes, or wedges. Leucine crystals are associated with liver disease. They are found in acid to neutral pH urine specimens and are yellow in color. One will notice the concentric circles and the radial striations. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. Question Difficulty: Level 3

Identify the urine sediment elements indicated by the arrow in the illustration: Cholesterol crystals Uric acid crystals Leucine crystals Cystine crystals

Fine granular casts Fine granular cases may represent degenerated cellular casts. They usually indicate renal parenchymal disease, or allograft rejection. WBC casts (leukocyte casts) are seen in renal infection or inflammation such as pyelonephritis. The identification of the cast as a WBC cast is supported by the appearance of WBCs outside of the cast. Hyaline casts, the type most commonly seen in urine sediment, have a refractive index similar to the urine in which they are suspended. For this reason, hyaline casts will appear almost invisible under brightfield microscopy, but are easily of seen by phase-contrast microscopy. Waxy casts are yellow, gray, or colorless and very refractive. They resemble short broad casts with broken ends and cracked edges. They are present in patients with severe renal failure, and can be due to allograft rejection. Question Difficulty: Level 4

Identify the urine sediment elements present in this illustration: WBC casts Hyaline casts Waxy casts Fine granular casts

Red blood cells This slide shows many red blood cells. Red blood cells (RBCs) are slightly smaller than WBCs and have a smooth, non-nucleated appearance. White blood cells have a rough appearance and contain granules and multilobed nuclei which fill out the cytoplasm of the cell. Squamous epithelial cells are the largest cells found in the urine sediment and can even be seen under low-power field. They may appear as clumps of cells and have a very large irregular-shaped cytoplasm with a prominent centrally located nucleus. Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. Question Difficulty: Level 2

Identify the urine sediment elements present in this image observed using brightfield microscopy. White blood cells Red blood cells Squamous epithelial cells Yeast

Cystine crystals Cystine crystals are characteristically seen as colorless hexagonal plates in acid urine. They may be confused with hexagonal uric acid crystals. They can be differentiated from uric acid by their solubility in dilute hydrochloric acid versus crystalline uric acid, which is not soluble in dilute hydrochloric acid. The cyanide-nitroprusside test can be used to confirm the presence of cystine in urine. Cystine crystals are not present in normal urine. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Uric acid crystals are variably shaped: they occur as flat diamond (four-sized), rhombic, lemon-shaped, or rarely hexagonal shapes with a yellowish or yellowish brown coloration. They are present in acid urine. They are polarizable and show various colors when polarized. They may be present in normal urine. Amorphous urates are found in acid urine and look like brick color or yellow/brown dust. Question Difficulty: Level 3

Identify the urine sediment elements shown by the arrow: Cholesterol crystals Uric acid crystals Amorphous urate crystals Cystine crystals

Uric acid crystals Uric acid crystals are variably shaped: they occur as flat diamond (four-sized), rhombic, lemon-shaped, or rarely hexagonal shapes with a yellowish or yellowish brown coloration. They are present in acid urine. They are polarizable and show various colors when polarized. They may be present in normal urine. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Amorphous urates are found in acid urine and look like brick color or yellow/brown dust. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. Question Difficulty: Level 5

Identify the urine sediment elements shown by the arrow: Cholesterol crystals Uric acid crystals Amorphous urate crystals Cystine crystals

Leucine crystals Leucine crystals appear as oily, highly refractile, yellow to brown spheroids with radial concentric laminations. They are found in acid urine in patients with maple syrup urine disease. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Uric acid crystals appear in acid urine and resemble yellow-brown four-sided flat planes, rosettes, or wedges. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. Question Difficulty: Level 4

Identify the urine sediment elements shown by the arrow: Cholesterol crystals Uric acid crystals Leucine crystals Cystine crystals

Mucus threads Mucus thread appear as long, thin ribbon like threads that are generally transparent. They are normal in small numbers in the urine. A cylindroid resembles a cast, with the exception that one end tapers out. They are considered to have the same significance as casts. Hyaline casts generally appear as colorless, homogeneous, and transparent with rounded ends. They can also be seen as a result of dehydration, after diuretic therapy, in renal disease, and transiently as a result of exercise. Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. Question Difficulty: Level 1

Identify the urine sediment elements shown by the arrow: Cylindroids Mucus threads Hyaline casts Budding yeast

WBC casts This is a WBC cast (leukocyte cast). WBC casts are seen in renal infection or inflammation such as pyelonephritis. The identification of the cast as a WBC cast is supported by the appearance of WBCs inside of the cast. Red blood cells (RBCs) have to be identified within the matrix of the cast. The identification of the cast as a red blood cell cast is supported by the appearance of RBCs outside of the cast. Unlike RBCs, the cells within this cast have nuclei. Waxy casts are yellow, gray, or colorless with and very refractive. They resemble short broad casts with broken ends and cracked edges. They are present in patients with severe renal failure, and can be due to allograft rejection. Granular casts are composed of plasma protein aggregates and cellular remnants. They usually indicate renal parenchymal disease, or allograft rejection. Granular casts appear as cylinders of coarse, or fine, highly refractive particles. Question Difficulty: Level 2

Identify the urine sediment elements shown by the arrow: WBC casts RBC casts Waxy casts Granular casts

Neutrophilic band The cell in the image is a banded neutrophil. "Bands" have a characteristic U-shaped nucleus. The cytoplasm contains neutral staining granules. Although it still has to mature into a segmented neutrophil, this stage can normally be found in the blood smears of healthy people. Metamyelocytes are more immature than bands and have a slightly indented nucleus, but much less indented than a band. Monocytes' nuclei can sometimes mimic those of bands since they can assume many different shapes. However, the chromatin in the monocyte's nucleus is looser, and their cytoplasm is blue and lacks the neutrophilic granules. A fully mature segmented neutrophil's nucleus is characteristically multi-lobed. The cytoplasm contains numerous small, neutral staining granules. Question Difficulty: Level 3

Identify the white blood cell in the center of this smear. Metamyelocyte Monocyte Neutrophilic band Segmented neutrophil

Arcanobacterium haemolyticum Arcanobacterium haemolyticum is the correct response. This exercise has been included to indicate that not all small beta hemolytic colonies growing on blood agar are necessarily streptococci. When a confirmatory gram stain should be performed is dependent on each laboratory practice and the clinical source. In this exercise Streptococcus sp. has been ruled out by observing gram-positive bacilli that are branching and in Chinese letter formations. The positive inverse CAMP reaction is characteristic of Arcanobacterium haemolyticum. Rothia dentocariosa colonies are bone-white to pink-gray and often appear heaped and cerebriform characteristically in a "spoke wheel" pattern, particularly in areas of confluent growth. Microscopically, the gram positive bacilli are more coryneform in appearance and do not arrange in Chinese letters. The CAMP reaction is negative. Bacillus cereus colonies are large, smooth, gray-white and spreading with irregular outer borders, and narrow zones of beta hemolysis. Microscopically gram-positive bacilli lying singly or in short chains with distinctive central and sub-termimal spherical to oval in shape endospores are distinctive. The reverse CAMP test is negative. Corynebacterium striatum colonies are relatively small, 1 - 1.5 mm in diameter, convex, smooth, gray-yellow and non-hemolytic. The gram stain is not distinctive, as gram-positive bacilli are arranged in small clusters. The reverse CAMP test is negative. Question Difficulty: Level 9

Illustrated growing on the surface of the blood agar plate shown in the upper left image are small distinctly beta hemolytic colonies suggestive of beta hemolytic streptococci, particularly when specimens are obtained from patients with an upper respiratory infection. Gram-positive bacilli in branching and Chinese letter formations are observed on gram stain as illustrated in the upper right image. Observe the reverse CAMP reaction in the lower image. From these observations, select from the choices shown below, the identification of this bacterial isolate. Rothia dentocariosa Bacillus cereus Arcanobacterium haemolyticum Corynebacterium striatum

Trypanosoma cruzi Trypanosoma cruzi is the correct response. The tryptomastigote Illustrated in the photomicrograph is distinct for T. cruzi by its "C" shape. Clearly indicated in the photograph is the posterior deep-staining dot-like kinetoplast and the anterior extension of the flagellum. Trypanosoma gambiense is an incorrect response. T. gambiense tryptomastigotes are long, slender and spindle shaped rather than in a "C" form. Trypanosoma rhodesiense is an incorrect response. T. rhosesiensetryptomastigotes are long, slender and spindle shaped rather than in a "C" form. Trypanosoma rangeli is an incorrect response. T. rangeli tryptomastigotes of are similar in appearance to those of T. gambiense and T. rhodesiense, and do not take on the "C" form. Question Difficulty: Level 9

Illustrated in the close-in photomicrograph of a stained blood smear is a circulating trypomastigote measuring 20 um. The disease represented by this peripheral blood form most commonly occurs in South and Latin America, often affecting children. Human infection is transmitted via an arthropod vector, the reduvid bug, resulting in an inflamed ulcer of the skin called a chagoma. Chronic infections in the form of tissue granulomas may disseminate to distant organs, often to the muscle of the heart. With this background, select from the multiple choices the name of the protozoan flagellate causing this disease. Trypanosoma gambiense Trypanosoma rhodesiense Trypanosoma cruzi Trypanosoma rangeli

Aspergillus niger Aspergillus niger is the correct response, as indicated by the species name. Characteristic is the black, peppered portion of the central mature colony. The reverse of the colony is not pigmented ruling out one of the dematiaceous fungi. Microscopically, the conidiophore is long and narrow (arrow), terminating in a globose vesicle surrounded by a single row of phialides that give rise to aggregates of small, spherical black-staining conidia. Conidia may become roughened when colonies mature. Aspergillus fumigatus is characterized by blue-green pigmented colonies and a fruiting head consisting of a single row of phialides over the top half of a club-shaped vesicle, giving rise to chains of small, spherical conidia. Aspergillus flavus colonies are yellow-brown and microscopically a single or double row of phialides cover the entire surface of a spherical vesicle, giving rise to short chains of spherical, brown-staining conidia. Aspergillus terreus colonies are also buff-brown with a finely granular surface. Microscopically The phialides over the top half of a club-shaped to spherical vesicle is similar in appearance to that of A. fumigatus, except they form a double row of shorter phialides that are arranged atop a club-shaped spherical vesicle from which straight chains of small, spherical conidia are produced. Question Difficulty: Level 1

Illustrated in the composite image on the left is a 72-hour growth on Sabouraud's dextrose agar of a finely granular, black pigmented colony obtained from a subcutaneous abscess at the site of an intravenous transfusion. The image to the right illustrates the microscopic appearance of a small inoculum taken from the surface of the center portion of the colony. A small spherical vesicle is surrounded by a row of phialides producing small, black-staining conidia. With these observations, select from the multiple choices the name of the fungus species as presented. Aspergillus fumigatus Aspergillus flavus Aspergillus niger Aspergillus terreus

Leishmania species Leishmania species is the correct response. The lesson from this exercise is not to immediately make a presumptive identification of Histoplasma when what appear to be yeast cells such as those presented in this exercise are observed. Rather, with closer observation look for the bar-like extensions from the nucleus of the small promastigotes that are distinctive of Leishmania species. Toxoplasma gondiiis an incorrect response. T. gondii tachyzoites are larger, measuring an average of 6 - 10 um, and are pyriform or bow-shaped with a distinct spherical nuclear karyosome. Onchocerca volvulus is an incorrect response. O. volvulus produces microfilaria that are long and thread-like, often arranged in spiral circles. They are not found intra-cellularly within inflammatory cells. Trypanosoma cruzi is an incorrect response. T. cruzi amastigotes range from 2 - 5 um in diameter, but are spherical and possess a distinct, deep staining karyosome. They more characteristically aggregate within tissue cells such as skeletal muscle fibers. Question Difficulty: Level 1

Illustrated in the high power image is an inflammatory reaction of skin lesion at the site of bite of a Phlebotimus sand-fly. Observed are large histiocytes within which are small intra-cytoplasmic 2 um in diameter oval cells that superficially have the appearance of the yeast cells of the fungus Histoplasma capsulatum. Note the distinctive bar-like kinetoplasts that lie adjacent to the nucleus of some of these cells (arrows). From the list of multiple choices, select the name of the protozoa as presented in this exercise Toxoplasma gondii Onchocerca volvulus Trypanosoma cruzi Leishmania species

Entamoeba histolytica/dispar Entamoeba histolytica/dispar is the correct response when isolated trophozoites as illustrated in the photomicrograph are observed. Issuing this report indicates that therapy may not be required depending on the clinical history and physical findings. If the differentiation between Entamoeba histolytica and Entamoeba dispar is required, antigen detection reagent kits are currently available for the performance of on-site assays, or for transport of fresh stool specimens to a reference laboratory. Entamoeba dispar does not invade tissue and red blood cells are rarely ingested. Entamoeba histolytica/polecki is an incorrect response. This species, endogenous in pigs, is rarely encountered in human stool specimens. Entamoeba hartmanni is an incorrect response. Entamoeba hartmanni trophozoites are similar in morphology to those of Entamoeba histolytica, but are small usually ranging <10 µm. They are rarely seen in stool specimens and could be identified by searching for the small cysts usually with no more than 2 nuclei and a chromatoidal bar with rounded ends. Entamoeba coli is an incorrect response. Entamoeba coli trophozoites are distinctive for the nucleus that has a large, eccentrically placed karyosome, a blotchy distribution of chromatin around the external ring, and cytoplasm that is coarse and junky rather than smooth and evenly distributed. This species is not pathogenic. Question Difficulty: Level 1

Illustrated in the image shown is a 20 µm amoebic trophozoite that was observed in a random stool specimen from a patient who had no symptoms of a parasitic infection. Several molecular based studies have found that in the analysis of stable DNA polymorphisms, several differences in DNA zymodeme patterns were found to encode for genetically different strains of Entamoeba histolytica. As some of these strains were found to be non-pathogenic, it has been recommended that the laboratory report be altered to draw attention to this possibility. Select from the choices below the report that should be issued. Entamoeba histolytica/dispar Entamoeba histolytica/polecki Entamoeba hartmanni Entamoeba coli

Entamoeba histolytica Entamoeba histolytica is the correct response. Distinctive is the nucleus with a tiny centrally located karyosome surrounded by an evenly dispersed and bead-like chromatin ring. The cytoplasm is smooth and finely granular. The ingestion of an erythrocyte as seen in the cytoplasm is also characteristic. Entamoeba hartmanni is the incorrect response. E. hartmanni trophozoites may morphologically simulate those of Entamoeba histolytica; however, they are much smaller in size and often have a chromatoidal bar with rounded ends. Typically, measure <10 µm. Entamoeba coli is an incorrect response. Entamoeba coli trophozoites are on the average larger than those of Entamoeba histolytica, with the nuclear karyosome being larger, eccentrically located, and surrounded by blotchy and chunky chromatin ring. The cytoplasm appears coarse and is commonly filled with undigested debris and scattered irregular sized vacuoles. Erythrocytes are not captured. Iodamoeba butschlii is an incorrect response. Iodamoeba trophozoites are small (6 - 12 µm), and distinctly have a small nucleus with a central karyosome with the distinctive absence of a chromatin ring, simulating a "ball in socket". Question Difficulty: Level 9

Illustrated in the image shown is a 20 µm trophozoite of an amoeba as microscopically observed in a trichrome-stained mount of a stool specimen obtained from a patient with recurrent diarrhea. Based on the morphology of the trophozoite, presumptively identify the parasitic trophozoite. Entamoeba hartmanni Entamoeba histolytica Entamoeba coli Iodamoeba butschlii

Ascaris lumbricoides Ascaris lumbricoides is the correct response. The ova are characteristically yellow-brown (bile-stained), oval or spherical, and characteristically have a thick, transparent, hyaline shell, covered by an albuminous coat. Fertilized eggs can be recognized by the cleavage of the internal yolk. A distinct larva may be seen in later stages of development. Intestinal symptoms range from mild to severe intestinal obstruction. Some patients will develop pulmonary symptoms due to the migration of larvae through the lungs and present with immune-mediated hypersensitivity pneumonia. The worms may cause an immune condition known as Löffler syndrome characterized by peripheral eosinophilia. Ancylostoma duodenale ova are of the same size as those of Ascaris, but are oval in outline. The shells are thin, smooth, transparent and non-pigmented. The yolk cells retract from beneath the shell leaving a distinctive clear space. Enterobius vermicularis ova are oval in outline and asymmetrical, with one side flattened simulating a deflated football. The shell is slightly thickened, smooth, and transparent. A well-developed larva is often is observed in mature ova. Trichuris trichiura ova are distinctly barrel-shaped, with a characteristic refractile, protruding convex, hyaline polar plug at either end. These ova are among the easiest to recognize when seen under microscopic examination. Question Difficulty: Level 4

Illustrated in the image shown is a 60 μm in diameter ovum that was observed in a diarrheal stool specimen obtained from a middle-aged male immigrant from Nigeria. He had suffered mild eosinophilic pneumonia a month before. What is best presumptive identification for the organism? Ancylostoma duodenale Enterobius vermicularis Ascaris lumbricoides Trichuris trichiura

Alcaligenes faecalis Alcaligenes faecalis is the correct response. Colonies on blood agar are gray and spreading. Plump Gram-negative coccobacilli are seen on Gram stain. Peritrichous flagella are seen on flagellar stain. A fruity odor of apples or strawberries may be noted. Carbohydrate utilization is asaccharolytic, oxidase is positive, nitrites are reduced with production of gas, citrate utilization is positive and urease is negative. A. faecalis exists in soil and water. Most human infections are opportunistic and are acquired from contact with moist items such as contaminated nebulizers, respirators and lavage fluids. Bordetella bronchiseptica colonies on blood agar are small, non-hemolytic and smooth with a "mercury droplet" appearance, translucent and non-pigmented. On Gram stain, non-discriminatory small Gram-negative coccobacilli are observed. Motility is positive also with peritrichous flagella. Nitrates are not reduced. Distinctive for the identification of B. bronchiseptica is the rapid production of urea, often visible within 4 hours of incubation. Moraxella catarrhalis colonies growing on blood agar are small, initially pinpoint in size after 24 hours incubation, and non-pigmented. Small, Gram-negative coccobacilli in pairs and short chains are observed in Gram stains. M. catarrhalis is non-motile; therefore, flagellae are not observed in flagella stains. Acid also is not produced from carbohydrates (asaccharolytic), nitrates are reduced and urease is also negative. Acinetobacter baumannii colonies growing on blood agar are relatively large, white, entire, convex and opaque. Gram-negative coccobacilli are distinctive for appearing as diplococci, and even Gram-positive. Peritrichous flagellae are not observed. Distinctive is the oxidative utilization of glucose and lactose on OF culture media. Oxidase is negative and nitrates are not reduced. Question Difficulty: Level 9

Illustrated in the image to the left are 3-day old colonies growing on blood agar. The colonies are gray and spreading, and a sweet, fruity odor is noted. Plump, Gram-negative coccobacilli are seen on Gram stain. This isolate belongs to the motile, non-fermenters with peritrichous flagella. Carbohydrate utilization is asaccharolytic. Nitrite reduction produces gas and citrate is positive. From the multiple choices, select the name of this isolate. Bordetella bronchiseptica Alcaligenes faecalis Moraxella catarrhalis Acinetobacter baumannii

Staphylococcus saprophyticus Staphylococcus saprophyticus is the correct response. Staphylococcus saprophyticus colonies are smooth but not pigmented and the gram-positive cocci in slide preparations are in small loose clusters and in tetrads, and not in non-grape like clusters. The coagulase test is negative. Demonstrating resistance to novobiocin is an additional identifying characteristic. S. saprophyticus is an agent of urinary tract infections. Staphylococcus aureus colonies are smooth and yellow-pigmented, and can also be distinguished by microscopically observing gram-positive cocci that form large tight grape-like clusters rather than arranging in small clusters and in tetrads. Most strains are novobiocin susceptible Species confirmation can be made by demonstrating a positive coagulase reaction. Staphylococcus epidermidis colonies are smooth but with a light gray pigmentation. Microscopic observation of gram stains reveals gram-positive positive cocci in small loose clusters with occasional tetrad formation. The coagulase test is negative. S. epidermidis is susceptible to novobiocin. Differentiation from S. saprophyticus may require carbohydrate utilization reactions utilizing kit systems or more advanced molecular assays. Micrococcus luteus colonies are smooth but distinctly yellow pigmented. Distinctive also is the tetrad formation of the gram positive cocci as observed microscopically in Gram stains. Most strains are novobiocin susceptipe. Confirmation can be made by demonstrating susceptibility to bacitracin ("A disc") and resistance to furazolidone. Question Difficulty: Level 1

Illustrated in the photograph are smooth, non-hemolytic, white 48 hour old colonies incubated at 37oC growing on the surface of blood agar. This isolate was recovered from a urine culture. Microscopic examination of a gram stain reveals small gram positive cocci arranged in loose clusters and in tetrads. This isolate is a common agent of urinary tract infections. Observe this novobiocin reaction. With these observations, select the from the multiple choices the name of this isolate. Staphylococcus aureus Staphylococcus epidermidis Staphylococcus saprophyticus Micrococcus luteus

Enterococcus faecalis A bacterial isolate recovered from the urinary tract that hydrolyzes esculin and grows in the presence of bile is most likely to be an Enterococcus species. Bacteroides fragilis also has the capability of growing in the presence of bile and hydrolyzing esculin; however, this species is an anaerobe that would not grow on the aerobic bile esculin agar used for the recovery of bacteria from urine specimens. Stenotrophomonas maltophilia hydrolyzes esculin; however, it does not grow in the presence of bile and therefore would not appear on bile esculin medium. Streptococcus mutans, one of the viridans streptococci, does not grow on bile esculin agar and does not hydrolyze esculin. Question Difficulty: Level 4

Illustrated in the photograph is a bile esculin agar plate inoculated with a bacterial isolate from a urinary tract infection. The most likely identification is: Stenotrophomonas maltophilia Streptococcus mutans Enterococcus faecalis Bacteroides fragilis

Taenia saginata Taenia saginata is the correct response. This proglottid, being longer than wide, is distinctive for having greater than 13 lateral uterine branches, that serves to rule out the other cestodes listed in this exercise. Taenia solium is an incorrect response. Although Taenia solium proglottids are longer than wide, they distinctly have less than 13 lateral uterine branches. Diphyllobothrium latum is an incorrect response. As the species name "latum" may indicate, Diphyllobothrium proglottids are broader than long. Hence, the name broad fish tapeworm. The uterus is in the form of a centrally placed coiled, compact rosette rather than in the form of lateral branches. Dipylidium caninum is an incorrect response. Dipylidium proglottids are also longer than wide, but are characterized by double genital pores, extending one from each side ("dipyle" = double gate), through which ova are excreted through vitaline ducts from each set of ovaries. Question Difficulty: Level 9

Illustrated in the photograph is a single proglottid representative of one of the cestode tapeworms. This proglottid is longer than wide and has well over 13 lateral uterine branches. Select the presumptive identification of this tapeworm proglottid. Taenia solium Taenia saginata Diphyllobothrium latum Dipylidium caninum

Prevotella melaninogenica Prevotella melaninogenica is the correct response. The presumptive identification can be suspected from the observation of black pigmented colonies, suggested by the species name. The presence of broad zones of beta hemolysis surrounding the colonies is also distinctive. Small gram-negative cocci lying singly are observed on gram stains. Most biochemical reactions are negative with the exception of the fermentation of glucose and lactose. P. melalinogenica is endemic in the oral cavity and may be recovered from cultures obtained from dental cavity infections. Isolates have also been recovered from human bite wounds. Veillonella parvula colonies on anaerobic blood agar are small, entire, convex, translucent, non-pigmented and non-beta hemolytic. Gram-negative cocci lying singly and in loose clusters are observed in Gram stains. Carbohydrate fermentation is absent (asaccharolytic). Additional biochemical assays may be required to make a definitive identification. Being part of the microbiota of the mouth and upper respiratory tract, V. parvula is often recovered in mixed cultures with other bacterial species, or less commonly from blood cultures from hospitalized patients with bacteremia and endocarditis. Bacterioides fragilis colonies on anaerobic blood agar are 1-4 mm in diameter, gray, convex, entire, semi-opaque, and non-pigmented and non-hemolytic. Older colonies may show internal ring-like whorls. Gram negative coccobacilli with rounded ends are observed in Gram stains. Indole and esculin hydrolysis reactions are positive. Glucose and select other carbohydrates including sucrose are fermented. B . fragilis, endogenous in the gastrointestinal tract, is a common isolate from a variety of infections. Fusobacterium nucleatum colonies on anaerobic blood agar are small, gray-white and convex with irregular borders and internal flecking. Beta hemolysis is not observed. Distinctive on gram stain are long and slender gram negative bacilli with tapered ends. Indole is positive. Carbohydrate fermentation of individual sugars is variable but positive among various bacterial strains (sacchrolytic). F. nucleatum is most commonly recovered from induced sputum specimens from hospitalized patients who develop upper respiratory infections. Question Difficulty: Level 1

Illustrated in the photograph is the 4 day slow growth of colonies recovered on an anaerobic culture. Note the small size of the colonies growing on anaerobic blood agar, distinctive for brown-black pigmentation surrounded by a wide zone of beta hemolysis. Gram stain revealed small, gram-negative coccobacilli. Most strains are biochemically inactive, although glucose and lactose fermentation are positive (saccharolytic). A common source would be from an infection of the oral cavity or from an infected human bite wound. From these observations, select from the multiple choices the identification of this isolate. Veillonella parvula Prevotella melaninogenica Bacteroides fragilis Fusobacterium nucleatum

Rothia dentocariosa Rothia dentocariosa is the correct response. Based on the species name of this isolate, common recovery from infected teeth and gums would indicate Rothia dentocariosa. This presumptive identification is supported by the heaped colonies with a light pink-white surface. Long, slender non-spore forming gram-positive bacilli and cocco-bacilli in a diphtheroidal arrangement are observed in gram stains. Key biochemical reactions include positive catalase, nitrate reduction, esculin hydrolysis, glucose fermentation, and pyrazinamidase. Corynebacterium striatum is incorrect because the colonies are relatively small, 1 - 1.5 mm in diameter, convex, smooth, gray-yellow without areas of heaped growth. Colonies are non-hemolytic. Microscopically observed in gram stains are small club-shaped, gram-positive bacilli in small clusters or in picket fence or Chinese letter arrangements. Esculin hydrolysis is negative and pyrazinamidase reactions are positive. Bacillus cereus is incorrect because colonies on blood agar are large, flat with a matte appearance, spreading, with gray-white round surfaces with fimbriated edges. Beta hemolysis is observed. Large, box-car shaped gram-positive bacilli are observed in microscopic mounts that lie singly or in short chains. Central and sub-terminal ellipsoidal spores are also distinctive. Lactobacillus species is incorrect because colonies growing on sheep blood agar are gray white, convex, smooth and do not form heaped areas of growth. Colonies may be alpha hemolytic. The microscopic observation of long, slender, non-spore forming gram-positive bacilli arranged in long chains rather than in diphtheroidal clusters is distinctive. Question Difficulty: Level 5

Illustrated in the photograph of the blood agar plate are slow-growing colonies after 72 hours incubation that are pink-white, appear dry, and heaped in areas of confluent growth (arrows). They were recovered from a tooth abscess of a 14 year old boy. Gram stain reveals short gram positive bacilli that characteristically are in a diphtheroidal arrangement. Key characteristics to provide a definitive identification include positive reactions for catalase, nitrate reduction, esculin, and pyrazinamidase. Based on these observations, select the presumptive identification of this isolate. Corynebacterium striatum Rothia dentocariosa Bacillus cereus Lactobacillus species

Bipolaris species Bipolaris species is the correct answer because the image displays septate hyphae that is dematiaceous with multi-celled macroconidia. The conidiophores are characteristically bent where the conidia are attached (at the arrow). The oval conidia are sympodically arranged with a slight protruding hilum. Bipolaris gets its name from germ tube formation that can occur at both ends of the conidia, when the fungus is incubated in a 25C water bath for 24 hours.

Illustrated in the photograph to the right is a lactophenol cotton blue preparation from a culture of a dematiaceous fungi. This fungi is known to cause phaeohyphomycosis and can be found in sites such as subcutaneous tissue, brain, eyes, and bones. Which of the following fungi is represented? Bipolaris species Cladophialophora species Curvularia species Alternaria species

Enterohemorhragic E.coli (EHEC) Enterohemorrhagic E. coli (EHEC) is the correct response. This sorbitol negative E. coli serotype produces shiga toxin, that along with other virulence factors produces human infections ranging from non-bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome that may be fatal. Of interest is the recommendation that susceptibility tests should not be performed as treatment with antibiotics may increase the production of shiga toxin resulting in prolonged or more severe complications. Shigella dysenteriae is incorrect because this species is a non-lactose fermenter and will not produce pigmented colonies on MacConkey agar. Most strains are sorbitol negative and also produce shiga toxin that can produce symptoms similar to E. coli (EHEC). Escherichia coli is incorrect because this species produces lactose fermenting colonies that appear similar to those seen in the Blood agar and MacConkey agar plates shown in this exercise; however, this species is sorbitol positive and will produce pigmented colonies on sorbitol MacConkey agar. Klebsiella aerogenes is incorrect because this species is a lactose fermenter and may produce colonies on MacConkey agar that are similar in appearance to those presented in this exercise; however, Klebsiella aerogenes can be distinguished from E. coli 0157:H7 by the production of sorbitol and the growth of pigmented colonies on sorbitol MacConkey agar. Question Difficulty: Level 1

Illustrated in the photograph to the right is the growth of bacterial colonies on blood and MacConkey agars. The media on the left with the red pigmentation on MacConkey agar indicates lactose fermentation. Note the sorbitol MacConkey agar plate on the right, which are growing non-pigmented, gray-white colonies. The isolate presented in this exercise is representative of the bacterial species that have been recovered from stool specimens in several outbreaks of patients with diarrhea following ingestion of contaminated ground beef. Which of the following is the identification of this isolate? Shigella dysenteriae Escherichia coli Enterohemorhragic E.coli (EHEC) Klebsiella aerogenes

Trichomonas vaginalis Trichomonas vaginalis is the correct response. The trophozoites, averaging between 10 - 12 um in diameter, have a single pyriform anterior placed nucleus that is distinctly slightly displaced from the outer membrane. A small, spherical, deeply stained para-basal body is present between the nucleus and the outer membrane from which numerous flagella arise. An axostyle transects the length of the body and extends from the distal end. Chilomastix mesnili is an incorrect response. Although the trophozoites of Chilomastix are similar in average size and in form to those of Trichomonas vaginalis, the nucleus is distinctly placed immediately adjacent to the anterior membrane with a "ball in socket" appearance. A prominent vacuolated cytosome is seen adjacent to the nucleus. Although anterior flagella are present, they are usually not visualized in stained smears. Endolimax nana is an incorrect response.The trophozoites are relatively small, averaging 5 - 8 um, and distinctly have a more centrally placed nucleus devoid of peripheral chromatin producing a "ball in socket" appearance. Flagellae and a central axostyle extending posteriorly are not observed. Iodamoeba butschlii is an incorrect response. The trophozoites are relatively larger, more spherical in outline, and measure up to 25 um. The nucleus is more centrally placed, and with a central karyosome and lack of an outer chromatin have a "ball in socket" appearance. Flagella and a posterior extending axostyle are not observed. Question Difficulty: Level 1

Illustrated in the photomicrograph is a 10 um in diameter, trophozoite observed in a trichrome-stained vaginal smear from a 39-year-old female experiencing a frothy vaginal discharge along with vaginal discomfort and pain on urination. What is the name of the invasive parasite? Chilomastix mesnili Endolimax nana Trichomonas vaginalis Iodamoeba butschlii

Microsporidium species Microsporum species is the correct response. The small size of the spores, the positive red staining with the Weber stain, and the central transverse septa are distinctive for Microsporidium. The oocysts of Cryptosporidium parvum, Isospora belli, and Cyclospora cayetanensis are larger than Microsporidium spores, ranging from 5 - 30 um), and are negative for the Weber stain. They do not possess an internal pink-staining band. The oocysts of Cryptosporidium and Cyclospora occupy the surface of the duodenal epithelial cells rather than invading the cytoplasm. Isospora sexual and asexual forms inhabit the lower intestine rather than the duodenum. Question Difficulty: Level 1

Illustrated in the photomicrograph is a high-power view of the elements within a duodenal aspirate preparation using a Weber Stain (Chromotope 2R, Fast Green, phosphotungstic acid). This stain is used to identify the tiny 1.5um pink-red staining spores, many with central transverse septa as: Cryptosporidium parvum Isospora belli Microsporidium species Cyclosopora cayetanensis

Wuchereria bancrofti Wuchereria bancrofti is the correct selection. Distinctive is the absence of nuclei extending into the tip of the tail of the adult worm. The common clinical diseases produced by this worm, residing in the lymphatics of the genital tract, are folliculitis, orchitis, and hydrocele. Brugia malayi is an incorrect response. B. malayi adult worms characteristically have two nuclei extending into the tip of the tail, separated by an open space measuring 10 um. A common clinical presentation in human infections with this species is tissue swelling known as elephantiasis, primarily involving the legs below the knee. Loa Loa is an incorrect response. Loa loa adult worms are distinctive for having an uninterrupted column of nuclei extending to the tip of the tail. The disease caused by this species results from the migration of adult worms through sub-cutaneous tissue. The thin skin below the conjunctival lining of the eye is one of the more common infections, resulting in a condition known as "Calabar swelling". Dirofilaria immitis is an incorrect response. D. immitis adult worms commonly reside in the right ventricle of the heart and the pulmonary artery of infected dogs. Rare cases of human infection have been reported, more commonly in infections of the lung where cough and chest pain are the primary symptoms. Question Difficulty: Level 9

Illustrated in the photomicrograph is the tail portion of an adult worm of a filarial nematode. Human infections with this nematode are more commonly found among those living in Southeast Asia, but may be observed in recent travelers there and to surrounding regions. These adult worms measure up to 300 um, occupy lymphatic channels and may cause lymphatic obstruction. Varying degrees of fever and chills may be experienced. The species indicated in this exercise by the orientation of nuclei within the tail section (arrows), more commonly involves the lymphatics of the genital tract resulting in orchitis and hydrocele. From the nematode species listed below, indicate the most likely species identification. Brugia malayi Wuchereria bancrofti Loa loa Dirofilaria immitis

Exophiala jeanselmei Exophiala jeanselmei is identified by observing the hyphae and the long conidiophores with a sharply pointed tip, producing loose clusters of dark-staining elliptical conidia. Hyphae become darkly pigmented as the colony matures. Fonsecaea pedrosoi is characterized by the sympodial branching of conidiophores produced from the sides of septate hyphae, simulating the prongs of a coat rack. Short chains of elliptical conidia are produced from the tips of these conidiophores. Cladophialophora carrionii are identified by observing microscopically the distinctive long, non-branched chains of elliptical conidia with each pair separated by a scar like dysjunctor. Phialophora richardsiae identification is made by the elongated narrow bottle-like phialides with a flat saucer-like cap at the open end from which loose clusters of conidia are produced. The colony morphology, although consistent with all of the listed species of chromomycosis, is not specific, since there is variation within different strains. Colonies are often yeast-like upon initial isolation, later become a velvety yellow-brown to black mold on maturity. Question Difficulty: Level 1

Illustrated in the top image is a 7-day-old colony with a gray-yellow, velvety mold and a black-staining perimeter extending to the reverse of the colony. Although characteristic of a colony of chomomycosis, what is the identification of fungi that produces the sharply pointed end of the phialide from which clusters of elliptical conidia are formed? Cladophialophora carrionii Phialophora richardsiae Exophiala jeanselmei Fonsecaea pedrosoi

Curvularia species Curvularia species is the correct response. The darkly pigmented colony is characteristic of one of the phaeohyphomyces, but is not species specific. Distinctive is the twisted geniculate conidiophores observed in stained microscopic mounts, from which are produced the symposial production of brown-stained macroconidia divided into 4 to 5 cells by transverse septa. Also distinctive is the overgrown cell within each of the conidia giving a curved shape. Curvularia species may be recovered from patients with allergic fungal sinusitis. Exserohilum macroconidia are long and multi-celled divided by transverse septa, and distinctive for the extended, prominent protruding extension from the hilar cell. Nigrospora spp conidia are borne singly from the tips of short inflated bulbous conidiophores. These conidia are non-septate, relatively large, sub-globose, and smooth with jet black pigmentation. Bipolaris macroconidia are long and elliptical to oval, each with a thick, smooth wall, separated into multiple equal sized cells, with each produced in a loose clustered, sympodial arrangement from the tips of curved, septate conidiophores. Question Difficulty: Level 9

Illustrated in the top image is a circumscribed three day old colony growing on Sabouraud's dextrose agar recovered from nasal washings of a patient with sinusitis. The colony with a dark green-gray, wooly surface mycelium is not exclusive. Gray-black pigment would be observed on the reverse side. Species identification must be made microscopically. Illustrated in the bottom image is the appearance of a tease mount made from the surface of the colony. From these observations, select from the list of multiple choices the identification of this fungal isolate. Exserohilum species Curvularia species Nigrospora species Bipolaris species

Phialophora richardsiae Phialophora richardsiae is the correct response. The slow-growing, brown hair-like colony with the dark brown-black reverse side is consistent with one of the agents of chromomycosis. The elongated narrow bottle-like phialides with a flat saucer-like cap at the open end from which loose clusters of conidia are produced (not observed in this image) is characteristic of Phialophora richardsiae. Current taxonomy has included this species in the genus Pleurostomophora, although the time honored genus name Phialophora is still used in the medical practice of most clinical mycology laboratories. Exophiala jeanselmei colonies are also slow growing but more velvety in consistency. The phialides are long and narrow, ending with a distinctive pointed terminal end, giving rise to clusters of elongated pigmented conidia, in keeping with the Exophiala-type sporulation. Fonsecaea pedrosoi sporulation is of the acrotheca type that is characterized by the sympodial branching of conidiophores produced from the ends of septate hyphae, simulating the prongs of a coat rack. Short chains of elliptical conidia are produced from the tips of these conidiophores. Cladophialophora carrionii sporulation is characterized by the production of long straight chains of elliptical, dark-staining conidia each separated by a delicate scar known as a dysjunctor. Phialides with a flattened saucer-shaped terminal end is not observed with Cladosporium sp. Question Difficulty: Level 1

Illustrated in the top image is a slow-growing 10-day-old colony growing on Sabouraud Dextrose with Brain Heart Infusion (SABHI) agar, recovered from a chronic recurrent cyst of the skin of the lower leg. The brown hair-like surface pigmentation appears brown-black when observed on the reverse of the colony. The identification is made by the appearance of the fruiting heads seen in the lower image. From the choices shown below, select the correct identification of this fungus. Phialophora richardsiae Exophiala jeanselmei Cladophialophora carrionii Fonsecaea pedrosoi

Cladophialophora carronii Cladophialophora carronii is the correct response. Colonies are slow growing and are not specific. Distinctive for making the identification of cladosporium-type sporulation, as seen in microscopic mounts, are hyphae giving rise to long chains of dark-staining, elliptical conidia each separated by a scar called a dysjunctor. Its colony is gray-green to black with a black reverse. Exophiala jeanselmei is incorrect. Exophiala jeanselmei sporulation is in the form of darkly stained conidiophores that branch from the pigmented hyphae. The conidiophores terminate in sharply pointed tips, from which loose clusters of small, elliptical pigmented conidia are produced. Fonsecaea pedrosoi is incorrect. Fonsecaea pedrosoi sporulation is of the acrotheca-type that is characterized by the sympodial branching of conidiophores produced from the ends of septate hyphae, simulating the prongs of a coat rack. Short chains of elliptical conidia are produced from the tips of these conidiophores. This species is the most common cause of chromoblastomycosis and produces a mixed type of sporulation that is characteristic of the Cladosporium, Phialophora, and Rhinocladiella species. Phialophora verrucosa is incorrect. Phialophora verrucosa sporulation is characterized by the production of short urn-shaped phialides with a narrow bottle-like opening derived laterally from the sides of the hyphae. Spherical of oval-shaped, yellow pigmented conidia are produced from within each phialide, forming loose aggregates at the terminal opening. Question Difficulty: Level 1

Illustrated in the top image is a slow-growing, 8-day-old colony growing on Sabouraud Dextrose with Brain Heart Infusion (SabHI) agar obtained from a darkened superficial skin infection. Although the colony is not specific for one of the fungal species causing chromomycosis, the black outer border that extends into the reverse of the colony is consistent. The identification is made by observing the distinctive conidiation illustrated in the bottom image. Which of the following organisms is represented by the description and images shown? Exophiala jeanselmei Fonsecaea pedrosoi Cladophialophora carronii Phialophora verrucosa

Mycobacterium tuberculosis Mycobacterium tuberculosis is the correct response. Bacterial cells observed in acid-fast stains that are prepared from surgical specimens or exudates are thin, slightly curved, red-pigmented and beaded. Bacilli observed microscopically in acid-fast stains prepared from colonies growing on agar surfaces are distinctly arranged in serpentine cords. Presumptive identifications can be made from these acid-fast preparations and additional biochemical reactions are available both in commercial kits or electronic instruments for confirmation. Mycobacterium kansasii bacilli as observed in acid fast stains prepared from clinical materials are typically long, straight and broad. Cross bands and bars may also be observed. Arrangement of bacilli in serpentine chords are not observed in acid-fast stains prepared from growing colonies. With experience when these bacilli are observed, a presumptive identification can be made. Observation of yellow, pigmented colonies growing on the surface of agar plates will confirm the presumptive identification. Mycobacterium avium/intracellulare bacilli are short and cocco-bacillary, uniform in staining and free of cross banding. Arrangement of bacilli in serpentine chords is not observed in acid fast stains prepared from colonies. Additional biochemical reactions may be required to make a more definitive identification when acid-fast stain morphology is not distinctive. Mycobacterium fortuitum bacilli as observed in acid-fast preparations are pleomorphic with a mixture of short, thick rods admixed with filamentous forms. Bacilli at times may appear beaded or swollen, but aggregation into serpentine chords is not observed. Additional biochemical reactions may be required to make a more definitive identification when acid-fast stain morphology is not distinctive. Question Difficulty: Level 9

Illustrated in the top photograph are acid-fast bacilli as they may appear in acid-fast stains prepared from a direct mount of infected tissue. These acid fast bacilli are thin, slightly curved, red-pigmented and beaded. The acid fast bacilli, as illustrated in the bottom photograph, aggregate in serpentine chords in stained mounts prepared from colonies growing on agar. From these observations, select the presumptive identification of this mycobacterium. Mycobacterium kansasii Mycobacterium avium/intracellulare Mycobacterium tuberculosis Mycobacterium fortuitum

Streptococcus species Streptococcus species is the correct response. Although isolated strains of an alpha hemolytic streptococcus may be vancomycin resistant, most are susceptible. Leuconostoc species are not alpha hemolytic when growing on blood agar, but categorically are vancomycin resistant. Once this species is identified in culture, the laboratory report should include a comment that the isolate is vancomycin resistant. Pediococcus species are not alpha hemolytic when growing on blood agar, but categorically are vancomycin resistant. Once this species is identified in culture, the laboratory report should include a comment that the isolate is vancomycin resistant. Staphylococcus species are not categorically vancomycin resistant; however, this resistance has become a major problem with Staphylococcus aureus that are recovered from a variety of human specimens, particularly strains recovered from hospitalized patients. Question Difficulty: Level 1

Illustrated in the top photograph are alpha-hemolytic, entire, gray-white convex colonies that are of a bacterial species that was found to be susceptible to vancomycin. In the lower photomicrograph are shown gram-positive cocci arranged in chains and in loose clusters that are not species distinctive. Select from the multiple choices the bacterial species that are uncommonly vancomycin resistant. Staphylococcus species Leuconostoc species Pediococcus species Streptococcus species

Streptococcus bovis Streptococcus bovis (Group D) is the correct response. The colonies on sheep blood agar after 48 hours incubation at 35oC are relatively small, entire, gray-white, and dry in consistency. Most strains are non-hemolytic. Gram positive cocci arranged in pairs and in moderately long chains are observed in gram stains. The positive Group D antigen latex agglutination test and the rapid production of esculin is key to the definitive identification, important for the close relationship with carcinoma of the colon and in the production of other colonic diseases. Enterococcus species colonies after 24 - 48 hours incubation on sheep blood agar are also relatively small, measuring 1 - 2 mm in diameter, and are dry and gray-white. In gram-stained preparations, Enterococcus species appear as spherical to ovoid gram-positive cocci that are arranged either in pairs or in short chains not exceeding 4-6 cells to a chain. Nosocomial urinary tract infections are common. Streptococcus agalactiae (Group B) colonies on blood agar are relatively large, smooth, transparent and surrounded by a distinct zone of beta hemolysis. Gram positive cocci arranged in short and moderately long chains up to 15 cells are observed in gram stains. The Group B antigen latex agglutination test is positive. S. agalactiae is commonly associated with in-utero and para-natal infections. Streptococcus anginosus (Group F) colonies are minute on blood agar with relatively large zones of beta hemolysis. The bacterial cells as observed in gram stains are not specific appearing as gram positive, are spherical or ovoid in shape, and are arranged in pairs or in short or relatively long chains. The Group F antigen latex agglutination test is positive. Additional characteristics may be required determined before a presumptive identification can be made. Purulent, deep-tissue abscesses as a complication of bacteremia are commonly encountered. Question Difficulty: Level 9

Illustrated in the top photograph are colonies on blood agar after 48-hour growth at 37oC incubation. The colonies are non-hemolytic, small, entire, smooth and gray-white. Small gram-positive cocci arranged in short chains are seen on gram stain as illustrated in the lower photomicrograph. Key to the identification is the rapid production of esculin. Identification of this isolate is important for its close relationship with carcinoma of the colon. Based on these observations, select from the multiple choices listed the name of this isolate. Enterococcus species Streptococcus agalactiae Streptococcus anginosus Streptococcus bovis

Chlamydoconidia present on the hyphae Candida albicans is the organism shown growing on SABHI. The characteristics of C. albicans on Cornmeal Tween 80 Agar are chlamydoconidia present on hyphae and spherical clusters of blastoconidia on psuedohyphae. The observation of delicate spicules radiating from the edge of the more mature colonies provide for a presumptive identification of Candida albicans as stated by the Clinical Laboratory and Standards Institute document M35-A2. Confirmation can be made with further testing including observing microscopic features when grown on Cornmeal Tween 80 Agar and demonstrating the production of germ tubes as observed in a slide mount prepared from a subculture from a tube of human or rabbit plasma inoculated with a sample from one of the colonies after 2 hours incubation. Candida parapsilosis colonies have a hair-like surface without radiating spicules. Microscopically the pattern of hyphal growth observed on Cornmeal Tween 80 Agar is colloquially referred to as "sagebrush" or "cross matchstick" patterns. Candida krusei will display branched psuedohyphae with clusters of elongated blastoconidia when grown on Cornmeal Tween 80 Agar. Candida glabrata colonies also have a smooth, white surface when grown on SABHI. On Cornmeal Tween 80 Agar small, tightly compacted blastoconidia without hyphae are observed. Question Difficulty: Level 1

Illustrated in the top photograph are smooth white yeast colonies growing on Sabouraud's heart infusion agar (SABHI agar) after 48 hours incubation at 30o C. The colonies were recovered from a post-operative wound infection in a 65-year-old man following an organ transplant. The bottom photograph is representative of more mature colonies after an additional 24-hour incubation. The isolate was also inoculated to Cornmeal Tween 80 Agar. What characteristics do you expect to see when examining the growth from this media? Sagebrush appearance of large hyphae Chlamydoconidia present on the hyphae Branched psuedohyphae with clusters of elongated blastoconidia Small, tightly compacted blastoconidia; no hyphae

Mucorspecies Mucor species is the correct response. The colony is not distinctive, although the dark outer pigment may suggest the production of pigmented hyphal segments or sporangia. A microscopic search throughout the mount failed to reveal rhizoids. Observed is the terminal end of a sporangiophore illustrating a distinctive bulbous columella, extending within a spherical, smooth-walled sporangium. Enclosed are tiny yellow-brown pigmented sporangiospores. Mucor sp. is one of the more common Zygomycetes recovered in laboratory cultures, either as an environmental contaminant or as a commensal pathogen. Circinella sporangiophores have a distinctive backward curve leading to globose sporangia produced at their tips. The sporangiophores are filled with sporangiospores that commonly are brown staining, as revealed by the darkened pigment in the colony surface mycelium. Rhizopus species produce root-like rhizoids that are in a distinctive "nodal" placement directly below the base of the sporangiophore. Each sporangiophore is straight at the tip rather than bulbous, also extending into a saclike sporangium enclosing sporangiospores. Syncephalastrum species also produce a spherical sporangium at the tip of a narrow sporangiphore. Distinctive is the cylindrical arrangement of elongated merosporangia produced from the surface of the sporangium simulating a "daisy petal". Tiny sporangiospores are aligned one after another in tandem within each merosporangium. Question Difficulty: Level 9

Illustrated in the top photograph is a 3 day old colony incubated at 30o C, with a border to border white hair-like mycelium with peripheral borders of brown and brown-black pigmentation. Although consistent with one of the Zygomycetes, a genus/species identification cannot be made. Observed in the high power photomicrograph is a lactophenol blue stained mount of a fruiting head in which a non-septate hypha terminates in a bulbous columella (arrow) that extends into a spherical sporangiophore. Rhizoids were not observed. From these observations, select from the multiple choices the name of this isolate. Circinella species Rhizopus species Syncephalastrum species Mucorspecies

Geotrichum candidum The correct answer is Geotrichum candidum. Geotrichum candidum has the microscopic appearance depicted in the bottom photograph (short septate hyphae, some of which may produce one of the corners a single germ tube from simulating a "hockey stick"). Although the colony is not specific, the silk-like aerial mycelium possibly suggest one of the yeast-like fungi that produces true hyphae. With some species the hyphae may be transformed into arthroconidia. Aureobasidium pullulans are characterized as "black yeasts" with dark pigmentation of colonies with a smooth, pasty surface. Dark-staining, non-budding arthroconidia in chains, with small single celled, non-encapsulated microconidia seen microscopically. Trichosporon beigelii colonies may also be yeast-like with a hair-like surface. True hyphae and budding arthroconidia are observed microscopically with the distinction that buds are from each of two corners forming what are called "rabbit ears", in contrast to the single "hockey stick" characteristic of Geotrichum. Phaeoannelomyces werneckii also produces "black yeast" colonies. Elongated two celled yeast cells are produced in which the daughter cell is separated from the mother cell by a distinct deeply staining transverse bar called an "annelide", which can be microscopically observed. Question Difficulty: Level 1

Illustrated in the top photograph is a 4-day-old white to cream-colored colony with a yeast-like background, but with the surface having a delicate silk-like consistency. Such colonies may be recovered as a contaminant in laboratory cultures. The identification is illustrated in a cornmeal agar mount shown in the bottom photograph. From these observations, the MOST likely identification of this yeast-like isolate is: The correct answer is highlighted below Trichosporon beigelii Aureobasidium pullulans Geotrichum candidum Phaeoannelomyces werneckii

Alternaria species Alternaria species is the correct response. The rapidly growing dematiaceous colony is not distinctive for any of the fungal species within this category. The species identification is made microscopically by observing the large, drumstick shaped multi-celled macroconidia divided by both longitudinal and transverse septa (muriform). Also distinctive is the elongated beak of one conidium butting against the rounded, blunt end of the next in the formation of chains. Alternaria are recovered most commonly as contaminants and rarely cause human infections. Curvularia species, Ulocladium species, and Stemphylium species also produce muriform macroconidia; however, do not form in chains but are individually supported by a separate conidiophore. Curvularia muriform macroconidia are distinctly composed of four or five cells separated by transverse septa. The second cell from the terminal end of the conidium continues to grow after the others have stopped, imparting a curved shape that has been described as a "boomerang". Ulocladium species macroconidia are borne from short, twisted "bent-knee" or geniculate conidiophores. Although muriform, the conidia are more spherical than those of Alternaria spp. and are borne singly and do not form in chains. Stemphylium species muriform macroconidia are superficially similar to those of Ulocladium spp. but are borne singly at the apex of short conidiophores appearing as a bale of cotton on a stick. Question Difficulty: Level 9

Illustrated in the top photograph is a relatively rapidly growing 4 day old colony on Sabouraud's dextrose agar incubated at 30o C. This colony was recovered as part of an environmental study. The colony has a wooly surface with distinctive black pigmentation both centrally and at the periphery, also visible when observed on the reverse of the Petri dish. Based on the microscopic presentation as illustrated in the bottom photomicrograph, select from the multiple choices the identification of this rapidly growing dematiaceous fungus. Curvularia species Ulocladium species Alternaria species Stemphylium species

Endolimax nana Endolimax nana is the correct response. The cysts are spherical to oval in shape, have a thin smooth outer border and characteristically possess up to 4 nuclei, each with a relatively large, centrally placed blotch-like karyosome. This species of amoeba are considered non-pathogenic and do not represent a parasitic disease when observed in stool specimens. Iodamoeba butschlii is an incorrect response. Iodamoeba ova are also of small in size (8-20 μm) and are oval in outline. Only a single nucleus with a large karyosome is observed. The presence of a prominent glycogen vacuole within the cytoplasm is an additional distinctive characteristic. Chilomastix mesnili is an incorrect response. Chilomastix ova are also small (6-10 μm), are lemon-shaped and possess only a single nucleus with a small karyosome that is placed adjacent to a hyaline knob beneath one side of the outer shell. Up to three flagella may be seen adjacent to the nucleus, along with a curved cytostome. Entamoeba hartmanni is an incorrect response. E. hartmanni cysts are spherical and small, 6-12 μm in diameter. Characteristic are one or two "entamoeba type" nuclei each with a central karyosome and a thin, regular bead-like chromatin ring. An intra-cytoplasmic chromatoid bar with rounded ends may also be observed. Question Difficulty: Level 9

Illustrated in the trichrome-stained mount of a stool specimen, submitted to rule out a parasitic infection, are small 8 - 10 μm amoebic cysts. Note the 4 nuclei each containing a large karyosome with no peripheral chromatin. From this high power microscopic view, select a presumptive identification from the multiple choice selections. Iodamoeba butschlii Chilomastix mesnili Endolimax nana Entamoeba hartmanni

Bacillus cereus Bacillus cereus is the correct response. Colonies on sheep blood agar are large, flat, feathery, spreading with a matte-like appearance with gray to white round surfaces and fimbriated edges, surrounded by broad zones of beta hemolysis. Large, box-car shaped Gram-positive bacilli are observed in Gram stained smear. The bacilli arrange singly or in short chains, with central and sub-terminal ellipsoidal spores that are not swollen. From the possible responses, B. cereus is the only bacterial species that produces spores. Erysipelothrix rhusiopathiae colonies on sheep blood agar are relatively small measuring 1 - 2 mm in diameter and are smooth, circular, convex, and translucent. This species may also produce large and rough colonies on sheep blood agar. Colonies show alpha hemolysis after prolonged incubation. Slender Gram positive bacilli or coccobacilli are observed microscopically, arranged singly or in short chains. In mature colonies short and long filaments may develop. Spores are not formed. Corynebacterium jeikeium colonies on sheep blood agar are small, 0.5 - 1.0 mm, gray to white, convex, and non-hemolytic. The bacterial species is pleomorphic and is observed as small Gram-positive bacilli arranged in V-forms or in picket fence like palisades. Spores are not produced. Lactobacillus species grow on sheep blood agar as small, pinpoint, alpha hemolytic colonies that may resemble streptococci or rough, gray colonies. Lactobacillus shows a pleomorphic morphology in stained smears, occurring as Gram positive bacilli in long, thin chaining bacilli, coccobacilli or spiral forms. Spores are not produced. Question Difficulty: Level 1

Illustrated in the upper blood agar plate are large, spreading, gray white colonies with a buttery consistency and fimbriated edges. Each colony is surrounded by broad zones of beta hemolysis. The Gram stain in the lower image reveals long, box-car ishaped, spore-forming Gram-positive bacilli. Lecithinase is produced on egg yolk agar. These findings are most consistent with a presumptive identification of which of the following? Erysipelothrix rhusiopathiae Corynebacterium jeikeium Bacillus cereus Lactobacillus species

Penicillium marnefei Penicillium marnefei is the correct selection. The microscopic features of this fruiting head are distinctive for Penicillium species. Unusual is the red diffusible pigmentation surrounding the colony as observed on the agar plate. This fungal species has been included in this exercise to introduce the features of this pathogenic Penicillium species, P. marneffei. This species is geographically endemic to Southeast Asia, but travelers to that part of the world may become infected. The infection may spread similar to that of disseminated histoplasmosis, particularly in patients with AIDS when a rapid identification is necessary followed by appropriate therapy. The selection of Paecilomyces, Scopulariopsis and Fusarium can be recorded as incorrect responses as none of these fungal genera produce the diffusible wine red pigment as observed in the colony selected for this exercise. Also, the distinctive fruiting head of Penicillium species also serves to eliminate these fungi from consideration. Question Difficulty: Level 9

Illustrated in the upper image is a 6 day old colony growing on the surface of Sabouraud Detrose agar. Note the distinct light green and pink granular colony surrounded with a reddish margin with diffusion of the wine-red pigment into the agar. This type of colony may be recovered from a sputum specimen of a person who had traveled to Southeast Asia. The lower image is of a microscopic mount stained with lacto-phenol blue. From these characteristics, select from the multiple choices the identification of this fungal isolate. Paecilomyces Scopulariopsis Penicillium marnefei Fusarium

Amebiasis Amebiasis is the correct selection. In the upper image, the size of the spherical shaped parasitic forms can be estimated to be 10 - 12 µm in comparison with the 2 - 3 µm size of the background inflammatory cells. A close view of one of these forms is observed in the lower image. This can be recognized as a trophozoite of Entamoeba histolytica by the distinctive central karyosome, even distribution of the ring of chromatin, and the finely granular cytoplasm providing for a diagnosis of "amebiasis". Giardiasis - the invasive Giardia trophozoites are distinctly oval in shape and have a pair of nuclei on either side of a vertical axostyle, fitted with a central para-basal body. These features resemble a "monkey face". Balantidiasis - the trophozoites of Balantidium coli are kidney shaped and large, approaching 100 µm in diameter, and have a large central dumbbell-shaped nucleus. Cysticercosis - is an infection in which cysts are commonly found in the brain and lungs. Humans become infected after ingesting the ova of Taenia solium contained in contaminated food. Once in the intestine, the ova hatch into larvae that enter the circulation. Although the larvae then permeate fibrous tissue, they do not cause an inflammatory response. Once the larvae lodge in the brain, lungs, or other tissue, they develop into a cyst that transforms into an adult Taenia tapeworm as part of its life cycle. Question Difficulty: Level 1

Illustrated in the upper image is a stained histological section of a bowel showing a heavy inflammatory reaction within which 10 - 12 µm spherical cysts are observed. The lower image is a close up view of one of the trophozoites from a smear preparation of the exudates. There is a distinctive central karyosome, even distribution of the ring of chromatin, and the finely granular cytoplasm. What disease can be presumptively reported? Giardiasis Balantidiasis Amebiasis Cysticercosis

Strongyloides stercoralis Strongyloides stercoralis is the correct response. The Strongyloides ovum, as illustrated in lower image, does not rule out one of the Hookworm species that have similar appearing ova. However, the short buccal cavity, as illustrated in this upper image, is distinctive for Strongyloides. Ancylostoma duodenale is an incorrect response. The smooth shelled ovum illustrated in the lower image is also characteristic of a Hookworm species. The short buccal cavity of the filariform larva as illustrated in the upper image is distinctive for Strongyloides, ruling out Ancylostoma which has a long buccal cavity. Necator americanus is an incorrect response. Necator ova, as illustrated in the lower image is consistent with one of the Hookworm species. The short buccal cavity as illustrated in the upper image is distinctive for Strongyloides and rules out the Necator species which has a long buccal cavity. Trichostrongylus species is an incorrect response. Trichostrongylus adults characteristically inhabit the intestines of various animals and birds. The buccal cavities of larvae are rudimentary or absent. The ova are similar to those of the hookworms, but are longer, up to 90 μm, with pointed rather than rounded ends. Question Difficulty: Level 1

Illustrated in the upper image is the anterior portion of a nematode filariform larva with a short buccal cavity. The ovum illustrated in the lower image is also part of the life cycle of this nematode. With these observations, what presumptive identification can be made from the parasite species listed below? Ancylostoma duodenale Necator americanus Strongyloides stercoralis Trichostrongylus spp.

Listeria monocytogenes Listeria monocytoges is the correct response. Colonies on blood agar are initially small, gray to yellow-white, surrounded by narrow zones of beta hemolysis that do not extend far beyond the outer margins. Microscopically are observed small gram-positive bacilli with rounded ends lying singly or in loose clusters . In older cultures, the bacilli may arrange in Chinese letter formations suggesting diphtheroids. "Umbrella" motility is observed on semi-solid motility media (image to the left in the composite); esculin hydrolysis is positive (image to the right). Rothia dentocariosa colonies are bone-white to gray and often appear heaped and cerebriform characteristically in a "spoke wheel" pattern, particularly in areas of confluent growth. Hemolysis is not observed. Gram positive bacilli or cocco-bacilli are observed in diphtheroidal arrangements. Motility is negative, although esculin hydrolysis is also positive. Arcanobacterium haemolyticum colonies are also small and beta hemolytic and are not discriminatory from L. monocytogenes. Microscopically observed in Gram stains are gram-positive bacilli that are branching and in Chinese letter formations that is not discriminatory. Motility and esculin reactions are negative, and a positive reverse CAMP reaction is distinctive. Erysipelothrix rhusiopathiae colonies are relatively small, 1 - 2 mm in diameter, convex, entire, and circular with light gray pigmentation. Beta hemolysis is absent. Slender gram positive bacilli or cocco-bacilli are observed microscopically, arranged singly or in short chains and devoid of spores. "Bottle brush" motility may be observed in semi-solid agar but esculin hydrolysis is negative. Question Difficulty: Level 1

Illustrated in the upper photograph are small, gray-white to light yellow colonies surrounded by zones of beta hemolysis. Short, gram-positive bacilli with rounded ends that lie singly or in loose clusters are observed in gram stains. Two key identifying features as illustrated in the lower photograph are a narrow band of "umbrella" motility observed beneath the surface of semi-solid motility medium and the deep black slant of positive esculin activity. This species may be recovered during influenza-like infections during 2nd and 3rd trimester of pregnancy. With these observations, select from the multiple choices the identification of this isolate. Rothia dentocariosa Listeria monocytogenes Arcanobacterium haemolyticum Erysipelothrix rhusiopathiae

Neisseria gonorrhoeae Neisseria gonorrhoeae is the correct response. The presumptive identification of the isolate presented in this exercise commonly becomes obvious if the clinical suspicion of gonorrhea is indicated. Distinctive is good growth of smooth, yellow-pigmented colonies on selective agar as observed in the upper photograph. Further observation of intracellular gram-negative diplococci in a gram stain of the specimen sediment, as illustrated in the lower photomicrograph, provide for a presumptive identification of Neisseria sp. A more definitive identification of N. gonorrhoeae is made by observing the selective utilization of dextrose. Endo-cervicitis with associated urethritis is clinically observed in females, while males most commonly present with urethritis and urethral discharge. In working with physician's offices, it is recommended that JEMBEC or other commercial transport media be used for transport of specimens obtained from patients with clinical signs of gonorrhea. Neisseria meningitidis colonies growing on selective agar with the observation of intra-cellular small gram-negative cocci as observed in mounts prepared from liquid specimens provide for a presumptive identification of Neisseria species. N. meningitidis can be excluded from the species identification of the isolate presented in this exercise by demonstrating the fermentation of both maltose and glucose, in contrast to the singular utilization of only glucose by N. gonorrhoeae. Aeromonas species can be excluded as colonies are small, opaque, gray-white and beta-hemolytic on blood agar. Bacilli instead of cocci are observed in gram stains. Distinctive is the production of acid also from sucrose and lactose in addition to glucose and maltose. Infections associated with skin wounds and lacerations exposed in water sports. Septicemia is commonly associated with Aeromonas species infections. Kingella kingae colonies grow well on blood agar with distinctive soft beta hemolysis. Short, plump, gram-negative cocco-bacillli in pairs and short chains are observed in gram stains. Distinctive is the production of acid from both glucose and maltose, in contrast to production from glucose alone. Also distinctive from Neisseria species, the catalase reaction for K. kingae is negative. Question Difficulty: Level 1

Illustrated in the upper photograph are smooth, entire, convex gray-yellow pigmented 48-hour old colonies growing on the surface of Thayer Martin medium. These isolates may be observed in cultures of specimens received from a physician's office obtained from patients with endocervicitis in females or urethral epididymitis in males. Illustrated in the lower photomicrograph is a gram stain prepared from the sediment of the specimen. These observations are sufficient to make a presumptive identification of Neisseria species. Further testing revealed the characteristic selective carbohydrate utilization of glucose with maltose utilization being negative. From the multiple choices, select the identification of this isolate. Neisseria meningitidis Neisseria gonorrhoeae Aeromonas species Kingella kingae

Corynebacterium jeikeium Corynebacterium jeikeium is the correct response. The small, smooth, entire gray-while, non-hemolytic colonies on blood agar are non-specific. The diphtheroid arrangement of elongated, non-spore forming Gram-positive bacilli provides a presumptive identification of Corynebacterium species; however, additional tests such as the observation of negative enzyme reactions are necessary to make a final species identification. Lactobacillus colonies on sheep blood agar after 24 hours incubation are also small, gray white, convex, and smooth and thus, are non-discriminatory. Observation of light alpha hemolysis would help to rule out Corynebacterium species. Microscopic examination of Gram stained mounts reveals long, slender, non-spore forming positive bacilli that are arranged in long chains, in contrast to the diphtheroid arrangement of Corynebacterium species. Rothia denticariosa colonies are pink-gray and often appear heaped and cerebriform characteristically in a "spoke wheel" pattern, particularly in areas of confluent growth. Hemolysis is not observed. Rothia is very pleomorphic; the Gram stain may show Gram positive bacilli or coccobacilli often in diphtheroid arrangement. Filamentous forms may be seen in older cultures. Most strains are biochemically active. Listeria monocytogenes colonies growing on blood agar are small, smooth, gray-white, and surrounded by narrow zones of soft beta hemolysis. Microscopically there are small non-spore forming Gram-positive bacilli with rounded ends lying singly in loose diphtheroid-like clusters. The demonstration of a positive CAMP test with external rather than inverse zones of hemolysis may be needed to confirm a final identification. Question Difficulty: Level 1

Illustrated in the upper photograph are tiny, gray-white, non-hemolytic colonies growing on the surface of blood agar. Recovery is most often from infections in immune-suppressed hospitalized patients. The Gram stain shows Gram-positive bacilli arranged in a "diphtheroid" pattern. Characteristic for making a species identification of this isolate are negative reactions for all enzymes. From these observations, select the presumptive identification of this isolate. Corynebacterium jeikeium Lactobacillus species Rothia dentocariosa Listeria monocytogenes

Taenia solium Taenia solium is the intended response. The cysticercus represents the extra-intestinal encysted larval form of T. solium. Human cysticercus infections may form in many organs, particularly in the brain where it is the cause of neurocystocercosis. The mode of infection is the inadvertant ingestion of gravid larvae in fecally contaminated food or water. Taenia saginata is an incorrect response as cysterceri are not included in the life cycle of this tapeworm, except in rare occasions. Serologic or immunologic procedures may be required to make this differentiation in rare cases where the species identification of a Taenia worm may be required. Dipylidium caninum is an incorrect response. D. caninum endemic tapeworm infections involve dogs and cats. Human infections are uncommon but may occur from ingestion of dog fleas. Cysticercus infections are not part of the life cycle of this tapeworm. Hymenolepis nana is an incorrect response. H. nana has the formation of a cysticercus within a variety of arthropods that serve as the intermediate host for human infections. After ingestion of an infected insect in contaminated foodstuffs, the adult worms attach within the human intestine. Cysticerci are not produced in the infected human host. Question Difficulty: Level 9

Illustrated in this compound Image is a section of brain to the left, within which a small cyst is observed (arrow). The image to the right is a low power microscopic close in view of the cyst, within which is observed a developing embryo, that can be recognized as a cysticercus . Select from the multiple choices the name of the human tapeworm for which a cysticercus cyst serves as an early stage in the development of its life cycle. Taenia solium Hymenolepis nana Taenia saginata Dipylidium caninum

Eikenella corrodens Illustrated in the photograph are colonies that are distinctly pitting the agar surface. This property, in conjunction with the detection of a bleach-like odor, provides a presumptive identification of Eikenella corrodens, which is the correct answer, as this is the only organism that does both. E. corrodens skin infections are almost always related to human bites, as it is part of the normal oral flora, in contrast to infections with Capnocytophaga canimorsus, which are related to dog bites. In addition, the colonies of C. canimorsus show and "gliding motility" rather than the pitting seen here, may swarm similar to Proteus spp. and do not have a bleach-like smell. Although the colonies of Moraxella lacunata (as the species name indicates) may pit the surface of agar, they do not have a bleach odor and would be extremely rarely associated with wound infections. Although Haemophilus aphrophilus can cause wound infections, the colonies do not pit the agar nor do they have a bleach odor. Question Difficulty: Level 3

Illustrated in this photograph are colonies growing on the surface of a chocolate agar plate. The colonies were recovered from a subcutaneous infection of the forearm and had a bleach odor. The most likely identification is: Moraxella lacunata Haemophilus aphrophilus Eikenella corrodens Capnocytophaga canimorsus

Salmonella typhi Salmonella typhi is the correct answer because the organism is a non lactose-fermenter (alkaline/acid KIA) that is producing small quantities of H2S, seen only as a small area of blackening in the angle of the KIA slant and along the streak mark in SIM agar. This pattern of H2S production is characteristic of Salmonella typhi. S. typhi also motile (as shown in the SIM agar tube) and is indole, VP and citrate negative. Salmonella typhimurium is incorrect because this organism produces large quantities of H2S and is citrate positive separating this species from Salmonella typhi. Proteus mirabilis is incorrect even though this species can produces large quantities of H2S; however, strains are VP positive and citrate positive. Citrobacter freundii is incorrect although it may produce smaller quantities of H2S; however, strains are citrate positive. Question Difficulty: Level 6

Illustrated in this photograph are the biochemical reactions of an unknown bacterial species produced in Kligler Iron Agar, Sulfide Indole Motility agar, indole broth, Voges Prokauer broth and Simmons citrate. The bacterial species most likely producing the reactions seen here is: Salmonella typhimurium Salmonella typhi Proteus mirabilis Citrobacter freundii

Mycobacterium kansasii Mycobacterium kansasii is the correct answer because M. kansasii is a photochromogen that will produce pigmentation in the light at 35C. Mycobacterium gordonae is incorrect because M. gordonae is a scotochromogen that will produce pigmentation in the dark and the light. Mycobacterium tuberculosis is incorrect because this species is neither a photochromogen nor scotochromogen, but part of the Mycobacterium tuberculosis complex that produces a buff colored pigment at 37C. Mycobacterium marinum is incorrect even though this species is a photochromogen, but the growth temperature separates it from M. kansasii. M. marinum grows at 30C instead of 35C. Question Difficulty: Level 5

Illustrated in this photograph are two Middlebrook 7H-11 plates incubated at 35°C, on which are growing colonies of an unknown Mycobacterium species. The plate on the left was incubated in the dark; the plate on the right had been exposed to light for 24 hours. The most likely identification is: Mycobacterium gordonae Mycobacterium kansasii Mycobacterium tuberculosis Mycobacterium marinum

Edwardsiella tarda XLD agar is a selective and differential medium. The agar is selective for gram negative enteric bacilli. It is differential for fermentation of lactose, sucrose, and/or xylose and lysine decarboxylation. Lactose, sucrose and/or xylose fermentation is seen on XLD by a yellow colony color. Lysine decarboxylation is seen on the agar as a red ring around the edge of the colony. H2S determination is also seen by a black colony color change. This image shows black colonies with a small red ring around the colony. This indicates that the colonies are H2S positive due to the black color change, and can decarboxylate lysine (red ring). Of the organisms given, Edwardsiella tarda is the only organism that would show a black colony with a red ring on XLD agar. Edwardsiella tarda is H2S positive and lysine decarboxylase positive. It is also positive for xylose fermentation, which will cause the colony to turn yellow. However, since it also decarboxylates lysine, the colony changes back to red. Xylose is present in limiting concentrations and is consumed. Then the organism will decarboxylate the lysine to cadaverine, an alkaline product, which will cause the colony to change from yellow, back to red. Proteus mirabilis is an incorrect answer because Proteus mirabilis ferments xylose and is lysine decarboxylase negative. P. mirabilis does produce H2S so the colony will appear black. However, the fermentation of xylose will cause the colony to be yellow. Since it then does not decarboxylate lysine, no alkaline products are formed, thus the colony remains yellow. Citrobacter koseri is incorrect because it is negative for H2S production and therefore would not produce black-appearing colonies on XLD agar. Citrobacter freundii does produce H2S. Shigella sonnei is incorrect because it is H2S negative, and would not appear as a black colony. S. sonnei also does not ferment any of the carbohydrates, thus it would appear as a clear (red) colony on XLD. Question Difficulty: Level 9

Illustrated in this photograph is a close-in view of colonies growing on the surface of xylose lysine deoxycholate (XLD) agar. The bacterial species most likely producing the colonies shown here is: Proteus mirabilis Citrobacter koseri Edwardsiella tarda Shigella sonnei

Micrococcus luteus The furazolidone disk can be used to separate Micrococcus species from Staphylococcus species. Micrococcus species are resistant to furazolidone, as shown in the image. Staphylococcus species are sensitive to furazolidone and thus a zone of inhibition would be observed around the disk. Since the FX disk is resistant (no zone of inhibition), the organism is a Micrococcus species, in this question, Micrococcus luteus. Micrococcus species also are susceptible to bacitracin, although the zone of inhibition to the A disk is often small (about 10 mm as show in the image). Staphylococcus saprophyticus can be ruled out in this question because S. saprophyticus is it is resistant to novobiocin and sensitive to furazolidone. The disk results seen in this image show resistance to furazolidone and sensitivity to novobiocin. Streptococcus pyogenes would also be susceptible to bacitracin but would give a much larger zone of inhibition around the A disk than is seen in this photograph. Staphylococcus epidermidis would be sensitive to the furazolidone disk and novobiocin disk. Question Difficulty: Level 8

Illustrated in this photograph is an agar plate on which an unknown species has been inoculated. A 5 µg novobiocin disk (NB), a 100 µg furazolidone disk (FX), and a 0.04 µg bacitracin (A) disk had been applied immediately after inoculation of the plate. Based on the pattern of the zones of inhibition to these three antibiotics, the most likely identification is: Micrococcus luteus Staphylococcus saprophyticus Streptococcus pyogenes Staphylococcus epidermidis

Denitrification of nitrates Denitrification of nitrates is correct because Acinetobacter species do not denitrify nitrogen, a characteristic that is commonly used in the identification of Pseudomonas species. Lack of motility is incorrect because all Acinetobacter species are nonmotile. Oxidation of glucose is incorrect. Acinetobacter species are divided into two groups; those that are glucose oxidizers and those that are non-glucose oxidizers. Most Acinetobacter baumannii are glucose oxidizers and Acinetobacter lwoffi are non-glucose oxidizers. Resistance to pencillin is incorrect because Acinetobacter species are resistant to beta-lactams and penicillin is a beta-lactam drug. Question Difficulty: Level 7

Illustrated in this photograph is the surface of a MacConkey agar plate growing colonies of a non-fermentative Gram negative bacillus recovered from a wound specimen. The iridescent light pink colonies suggest Acinetobacter species. Each of the following characteristics are helpful in supporting this identification EXCEPT: Lack of motility Oxidation of glucose Denitrification of nitrates Resistance to penicillin

Listeria monocytogenes The correct answer is Listeria monocytogenes. The SIM tube illustrates the typical subsurface umbrella-shaped motility characteristic of Listeria monocytogenes. The motility is best demonstrated at incubation temperatures of 25° - 30°C. The hydrolysis of esculin as indicated by the black pigment in the right tube helps to confirm this identification as all of the other bacterial species listed are esculin negative. This is an important differentiation from Kurthia species, most strains of which are motile. E. rhusiopathiae and Lactobacillus species are not motile. Question Difficulty: Level 4

Illustrated in this photograph to the right is a sulfide indole motility (SIM) tube (left) and an esculin hydrolysis slant (right) after inoculation with an unknown gram positive bacillus and incubation at 30°C for 24 hours. Based on the reactions observed, the most likely identification is: Listeria monocytogenes Erysipelothrix rhusiopathiae Kurthia species Lactobacillus species

Klebsiella oxytoca All four biochemical tests shown are demonstrating a positive reaction. The bacterial species that best fits these results is Klebsiella oxytoca. The partial or weak urease reaction (slant only) in particular is in keeping with the genus Klebsiella. K. oxytoca is the only Klebsiella species that is indole positive. Salmonella typhimurium is ruled out by these reactions because it does not produce indole and is also urease negative. Citrobacter koseri is ruled out by these reactions because it is negative for Voges Proskauer. Enterobacter cloacae is ruled out because none of the Enterobacter species produce indole. Question Difficulty: Level 6

Illustrated in this photograph, reading from left to right, are biochemical reactions for indole, Voges Proskauer, Simmons citrate, and Christensen's urea. The bacterial species providing the best fit for the reactions illustrated is: Salmonella typhimurium Citrobacter koseri Klebsiella oxytoca Enterobacter cloacae

Shigella sonnei Illustrated in this photograph is a bacterial species that is a non lactose fermenter (alkaline/acid reaction on KIA), that is non motile (SIM) and is inactive for all the biochemical characteristics included here. Shigella is the genus of the Enterobacteriaceae that first comes to mind when a non-lactose fermenter produces a series of negative reactions. Shigella sonnei is also indole negative, making it the correct response in this exercise. Escherichia coli is a lactose fermenter, has a (A/A)on KIA with gas production, motile, and is indole positive.Yersinia species, particularly Y. enterocolitica, is another non lactose fermenter that should also be considered when a series of negative reactions is observed. However, 50% of Y. enterocolitica and 100% of Y. frederikensii are indole positive. Providencia stuartii, although a non lactose fermenter, is positive for all the other reactions included in this exercise. Question Difficulty: Level 5

Illustrated in this photograph, reading from left to right, are tubes of Kligler Iron agar (KIA), Sulfide Indole Motility agar, indole broth, Voges Proskauer broth and Simmons citrate. The bacterial species most likely producing the reactions illustrated here is: Shigella sonnei Escherichia coli Yersinia frederikensii Providencia stuartii

Strong urease activity Strong phenoloxidase activity Observed in this photomicrograph is a cluster of spherical, somewhat irregularly sized yeast cells that appear to be separated by capsular material. A few of the cells show a single bud connected by a delicate, hair-like attachment. These are microscopic characteristics suspicious for Cryptococcus species. A rapid urease reaction would support this identification; and, the demonstration of strong phenoloxidase activity, either with a caffeic acid strip or with the use of bird seed agar, would confirm the identification of Cryptococcus neoformans. One of the key characteristics in the identification of Torulopsis (Candida) glabrata is the selective assimilation of glucose and trehalose. Most Cryptococcus species, on the other hand, are saccharolytic and assimilate several carbohydrates in addition to trehalose. The Cryptococci are not ascosporogenous yeasts; therefore, ascospores would never be observed. Question Difficulty: Level 8

Illustrated in this photomicrograph of a lactophenol blue preparation of a urine sediment is a cluster of yeast cells that were presumptively identified as Cryptococcus species. Further characteristics that may assist in confirming this identification are: Strong urease activity Selective assimilation of dextrose and trehalose Production of ascospores on ascospore agar Strong phenoloxidase activity

Which of the following would NOT be considered a molecular testing technique used in the clinical laboratory to identify unique nucleic acid sequences? Enzymatic cleavage of nucleic acids Enzymatic amplification of target sequences Hybridization with nucleic acid probes Immunoassays

Immunoassays Nucleic acid-based methods are designed to detect changes at the DNA (deoxyribonucleic acid) or RNA (ribonucleic acid) level rather than to detect a synthesized gene product, such as a protein detected in immunoassays. Molecular testing technique used in the clinical laboratory to identify unique nucleic acid sequences include enzymatic cleavage of nucleic acids, enzymatic amplification of target sequences, hybridization with nucleic acid probes, and gel electrophoresis. Question Difficulty: Level 8

Which of the following patients are at risk for transfusion-associated graft versus host disease (TA-GVHD) and require irradiated cellular blood products? Immunocompromised patients including neonates less than 4 months of age and patients receiving chemotherapy. Post-surgical recipients of pre-operatively donated autologous blood products. Patients with chronic anemias who are frequently transfused cellular blood products. Patients with a history of urticarial (allergic) reactions to transfused blood products.

Immunocompromised patients including neonates less than 4 months of age and patients receiving chemotherapy. Certain recipients have increased risk for developing TA-GVHD. They are: Neonates less than 4 months of age Recipients with a congenital or acquired immunodeficiency, such as bone marrow or stem cell recipients, and patients receiving chemotherapy Recipients of directed donor units from a blood relative Recipients of HLA matched or crossmatched platelets or granulocytes Recipients of autologous donations are not at risk of TA-GVHD because they are receiving blood they donated for their own post-operative use. Patients who are frequently transfused with cellular blood products to treat chronic anemia are at higher risk of alloimmunization but do not typically require irradiated blood. Patients with a history of urticarial (allergic) reactions to transfusion typically require pre-medication prior to transfusion with antihistamine medications. More severe reactions such as anaphylaxis due to IgA deficiency may require transfusion of washed blood products or IgA deficient plasma products. Question Difficulty: Level 7

Uremia Teardrop cells are not typically seen in uremia; echinocytes (burr cells) are associated with uremia. Teardrop cells (dacryocytes) are marked by blue arrows. Teardrop cells are round cells elongated at one end to form a teardrop or pear shape. Teardrop cells form as they attempt to navigate through fibrotic bone marrow and/or an enlarged spleen. Teardrop cells can also form after red blood cells containing inclusions traverse the spleen; their cell membranes become stretched as splenic macrophages attempt to remove inclusions. They are mainly seen in primary myelofibrosis, myelophthisic anemia, and thalassemia. Question Difficulty: Level 8

In all of the following conditions, the red blood cell morphology marked by the blue arrows is a typical finding, EXCEPT? Myelofibrosis Uremia Myelophthisic anemia Thalassemia

Brain Kernicterus literally means "yellow kern," with kern indicating the most commonly afflicted portion of the brain and is associated with severe jaundice. This condition is caused by a build up of unconjugated bilirubin in the bloodstream from the breakdown of red blood cells. Question Difficulty: Level 3

In the condition kernicterus, the abnormal accumulation of bilirubin occurs in what tissue? Brain Liver Kidney Blood

South American trypanosomiasis (Chaga's disease) South American trypanosomiasis (Chaga's disease) is the correct response. The observation of "C"-shaped trypomastigotes is distinctive. Several years ago, Avila, et al (J Clin Microbiol 1993;33:2421) developed a PCR/DNA screening test for detecting of chronic Chagas' disease antigens in blood bank donor blood. They demonstrated 100% sensitivity compared with serological tests using a specific labeled nucleotide probe. African trypanosomiasis ("sleeping sickness") is an incorrect response for this exercise. The circulating trypomastigotes are more spiral and "S" than "C"- shaped in form. PCR/DNA assays specific for African Trypanosma species have also been developed, obviously that would be negative when testing for the identification of Trypanosoma cruzi. Leishmaniasis ("kala azar") is an incorrect response. The trypomastigotes of Leishmania species are more confined to localized granulomas, particularly in heart muscle. Those circulating also are C-shaped, but considerably smaller and few in number. Molecular assays for Chaga's disease obviously would be negative. Onchocerciasis ("river blindness") is an incorrect response.This infection is confined to inflammatory nodules, particularly of the eye.Microfilaria wander from the nodule through the subcutaneous tissue to the eye.These microfilaria do not circulate in the blood. Question Difficulty: Level 9

In the photomicrograph of a blood smear are observed circulating trypomastigotes. The disease caused by this hemoflagellate has become of concern in the United States as infections have increased among recent travelers to South America and among the high number of immigrants. Concern has increased for the spread of disease through blood transfusions. Specific PCR/DNA assays are now being used to detect antigens of infective trypomastigotes in donor blood. From the multiple choices, select the disease that is being screened. African trypanosomiasis ("sleeping sickness") South American trypanosomiasis (Chaga's disease) Leishmaniasis ("kala azar") Onchocerciasis ("river blindness")

Serratia marcescens Serratia marcescens is the correct response. The red pigmentation observed on the colonies growing on MacConkey agar suggests lactose fermentation; however, this can be ruled out, as the pigment does not extend into the adjacent agar. Rather a bacterial species that inherently produces pigmented colonies must be considered. As Serratia marcescens would be among the first choices, a positive reaction on DNase, as illustrated in the image to the right, supports this presumptive identification. Additional key reactions in making a definitive identification include positive reactions for ornithine decarboxylase, citrate, Voges Proskauer, and the hydrolysis of gelatin. Proteus vulgaris, Providencia stuartii, and Citrobacter koseri can be ruled out as none of these Enterobacteriaceae produce DNase. Variation of the other chemical reactions among these genus/species would be observed that would not serve for elimination as part of this exercise. Question Difficulty: Level 1

In the upper bi-plate image are shown colonies growing on MacConkey (left), and on blood agar (right). Relatively large confluent gray white colonies are observed growing on blood agar, while smaller smooth convex colonies with a deep red pigmentation are growing on MacConkey agar. Note that the pigment is confined to the colonies growing on MacConkey agar that does not diffuse into the adjacent agar. In follow-up to making a presumptive identification, observe that the colonies growing on the DNase agar in the lower image (right) show a positive reaction with clearing of the adjacent agar, compared to the growth of a negative control growing in the streak lines to the left. From these observations, select from the multiple choices the presumptive identification of this isolate. Proteus vulgaris Serratia marcescens Providencia stuartii Citrobacter koseri

Hymenolepis nana Hymenolepis nana is the intended response. The small "dwarf" size and the tiny scolex as seen under low-power magnification with a distinctive protruding armed rostellum and a circle of hooklets are key to its identification. Taenia solium is an incorrect response. T. solium scoleces also have an armed rostellum, but are larger and more flattened on the anterior surface, and are non-protruding. Taenia saginata is an incorrect response. T. saginata scoleces have only four suckers and have a flat anterior end that is devoid of an armed rostellum. Diphyllobothrium latum is an incorrect response. D. latum adult worm scoleces are long and narrow with a dorso-ventral groove ("bothrium") surrounded on either side by lateral lip-like folds ("phyllo"). Question Difficulty: Level 1

In the upper photograph is seen a segment of large bowel to include a short, thin, thread-like adult worm. In the lower photograph is show the scolex of this worm, with a protruding armed scolex and a row of hooklets. Also known as the "dwarf tapeworm", this cestode more commonly causes intestinal infections in children. Select the presumptive identification of this ovum from the choices shown below. Taenia saginata Hymenolepis nana Taenia solium Diphyllobothrium latum

Pleurostomophora richardsiae Pleurostomophora richardsiae is the correct answer because this fungal species produces phialides with distinct flattened or saucer like collarettes. Phialophora verrucosa is incorrect because this fungal species produces deeper, more cup or flask-shaped phialides. Exophiala jeanselmei is incorrect because this fungal species produces long, slender, tapered phialides that may appear roughened at the tip where the rings or annellides have formed. Scopulariopsis brumptii is incorrect because this fungal species produces lemon-shaped, flat, truncated base phialides, rather than the open phialides seen with these other species. Often resembles Penicillium at first glance. Question Difficulty: Level 6

In this photomicrograph, several dematiaceous hyphae with long, flask-shaped, tapered phialides that have flat saucer-like terminus are seen (arrow). This feature is most characteristic of which of the following fungal species: Phialophora verrucosa Pleurostomophora richardsiae Exophiala jeanselmei Scopulariopsis brumptii

a-beta-lipoproteinemia The intended response is a-beta-lipoproteinemia. The distorted erythrocytes illustrated in the photograph are called schizocytes, or schistocytes. They are formed when fibrin is deposited within the vasculature and red cells must find their way around them as occurs in disseminated intravascular coagulation. These aberrant red cells may be secondary to trauma to red cells as they pass through prosthetic valves and they may accompany extensive burns, among other disorders. A-beta-lipoproteinemia is a condition associated with acanthocytes rather than schizocytes. Acanthocytes have less red cell distortion, with spikes much shorter and more delicate, and the majority of the red cells being effected. Question Difficulty: Level 5

In which of the following conditions would a technologist NOT expect to see the misshaped "spiked" erythrocytes included in the photograph? Cardiac valve prosthesis a-beta-lipoproteinemia Disseminated intravascular coagulation Extensive burns

Which set of chemistry results would most likely occur during hemolytic crisis in alpha thalassemia intermedia? Decreased lactate dehydrogenase and bilirubin, increased haptoglobin Increased lactate dehydrogenase and bilirubin, decreased haptoglobin Increased lactate dehydrogenase and bilirubin, normal haptoglobin Normal lactate dehydrogenase and bilirubin, decreased haptoglobin

Increased lactate dehydrogenase and bilirubin, normal haptoglobin Alpha thalassemia is a hemolytic anemia. In most hemolytic anemias the LD and bilirubin are increased while the haptoglobin is decreased. However, because haptoglobin binds to the alpha chain portion of hemoglobin, it usually remains at normal levels due to the absence of alpha chains in the destroyed cells. Question Difficulty: Level 8

Elizabethkingia is the new genus name for the bacterium formerly called Chryseobacterium meningosepticum, an important agent of neonatal mentingitis (now E. meningoseptica). What biochemical characteristic is unique for the family Flavobacteriaceae among the nonfermenters? Indole production Esculin hydrolysis Glucose oxidation Resistance to penicillin

Indole production Among the nonfermenters, the production of indole points to one of the Flavobacteriaceae, including E. meningoseptica. Indole production is weak; therefore, extraction with xylene and reaction with Ehrlich's rather than Kovac's reagent is required for its detection in the standard laboratory procedure. Esculin hydrolysis, oxidation of glucose and susceptibility profiles to penicillin are variable among the Flavobacteriaceae and do not represent characteristics unique to this group. Question Difficulty: Level 7

The first time a cell containing HbSS is deoxygenated, it forms a sickle cell. Upon reoxygenation, which of the following is true for the sickle cell? It will remain sickled. It will return to a normal biconcave shape. It will turn into a codocyte (target cell). It will appear as an echinocyte (burr cell).

It will return to a normal biconcave shape. Initially, sickling is reversible. The red blood cell (RBC) can return to its normal biconcave shapte. Upon repeated sickling and unsickling, cells with HbSS become irreversibly sickled. Repeated cycles of sickling cause the RBC membrane to become rigid. At this point the sickle cell becomes irreversibly sickled, whether the hemoglobin is oxygenated or deoxygenated. Target cells (codocytes) appear as a target or bull's-eye. They can found in a number of conditions, such as thalassemia, liver disease, hemoglobinopathies, and others. Burr cells (echinocytes) appear as spiculated with short, equally spaced projections around the entire surface of the cell. They can be found in liver disease, uremia, and other conditions. Question Difficulty: Level 7

Donor red blood cells (RBCs) were collected on July 12th of this year. The RBCs were then frozen in glycerol on July 17th (5 days later) and stored at -65o C. What should the expiration date read on the frozen RBC unit? July 12th; 1 year from collection date July 17th; 1 year from freezing date July 12th; 10 years from collection date July 17th; 10 years from freezing date

July 17th; 10 years from freezing date The correct answer is July 17th; 10 years from freezing date. Blood is sometimes frozen to maintain an inventory of rare units or extend the expiration date of autologous units. Currently, the FDA licenses frozen RBCs for a period of 10 years following the addition of glycerol as a cryopreservation agent. Glycerol is the most commonly used agent and is added to RBCs within 6 days of collection. The recommended interval between removing the RBC unit from refrigeration and placing the glycerolized cells in the freezer should not exceed 4 hours. So, based on this information, the correct answer should be 10 years from the date of freezing, which in our case is July 17th; 10 years from freezing date. When the blood is needed, it is thawed and deglycerolized and the expiration date is changed to 24 hours from the time of thawing. Question Difficulty: Level 9

K negative; Fya negative This patient does not currently demonstrate any antibodies, but his historical clinically significant unexpected antibodies cannot be ignored. He must receive units that lack the K and Fya antigens. If the patient is transfused with red cells positive for antigens for which he has made the corresponding antibody, this could lead to a hemolytic transfusion reaction. Any patient with a history of unexpected clinically significant antibodies requires antigen negative units, even if the corresponding antibodies are not currently reacting in routine testing. Question Difficulty: Level 9

K negative Fya negative K negative; Fya negative As long as you perform a full crossmatch and it is compatible, you can use any unit of red cells

While ABO, Rh, Kell, Duffy, Kidd, SsU are clinically significant, which of the following antibodies generally react at only the Coombs phase (also known as Antihuman Globulin phase)? Rh and Kell antibodies ABO antibodies Kell, Duffy and Kidd antibodies SsU and Kidd antibodies

Kell, Duffy and Kidd antibodies The correct answer is: Kell, Duffy and Kidd antibodies. Kell, Duffy and Kidd antibodies are not only clinically significant, but they also react at only the Coombs phase. Rh antibodies can react at immediate spin and 37°C as well. ABO antibodies react at immediate spin and can react at 37°C as well. SsU antibodies can react at both immediate spin and at 37o phases as well. Question Difficulty: Level 9

Antibodies within which of the following blood group systems are known to result in severe hemolytic transfusion reactions, but are not always detected during pre-transfusion testing in the blood bank? Duffy Kell Lewis Kidd

Kidd The correct answer is: Kidd. Kidd is the most common cause of delayed transfusion reactions. The antibody titer for Kidd can drop to undetectable levels several months after primary exposure to the antigen. Upon subsequent exposure to the antigen, a robust antibody response and hemolysis of the offending donor red cells occurs. This is also referred to as an anamnestic response. Duffy Blood Group System antibodies have been implicated in HTRs and DHTRs, but not as frequently implicated in DHTRs as Kidd antibodies. Kell antibodies have been implicated in severe HTRs and less frequently DHTRs. Lewis antibodies are often naturally-occurring, primarily IgM antibodies that rarely cause HTRs. Question Difficulty: Level 9

Nitric oxide is associated with the prevention of vaso-occlusion by decreasing cellular adherence to endothelium. Which amino acid is decreased in patients with sickle cell disease and is needed as a substrate to produce nitric oxide? L-arginine L-glutamine L-lysine L-tyrosine

L-arginine The amino acid, L-arginine is a substrate needed to produce nitric oxide. Low arginine bioavailability in sickle cell disease is associated with elevated levels of nitric oxide synthase inhibitor, among other complications. Question Difficulty: Level 8

A phlebotomist must perform a skin puncture to obtain capillary specimens for a complete blood count (CBC), a plasma-based chemistry test, and a serum-based immunology test. The microcollection containers that will be used are lavender top containing EDTA anticoagulant, green top containing heparin anticoagulant, and gold top containing no anticoagulant. Which microcollection container should be collected first? Lavender top Green top Gold top Red top

Lavender top Microcontainer collection order of draw differs from regular peripheral blood collection order of draw. The blood tends to clot faster when collected from a capillary skin puncture and care must be taken to prevent mini clots or platelet aggregation. When performing a capillary draw, the lavender top (EDTA) container is obtained first. This decreases the possibility of clots in the container which would invalidate the results of the complete blood count test. After the lavender is drawn, other containers with anticoagulants would be collected (e.g. green top), and containers without anticoagulants would be collected last (e.g. gold top, red top). Question Difficulty: Level 7

In which of the following disorders would you probably observe coarse basophilic stippling on a Wright-stained peripheral blood smear? Hemolytic anemia Sideroblastic anemia Multiple myeloma Lead poisoning

Lead poisoning Coarse basophilic stippling may be observed on the Wright-stained peripheral blood smear in cases of thalassemia or lead poisoning. In hemolytic anemias, a hallmark abnormality seen on the Wright-stained peripheral blood smear are spherocytes. In sideroblastic anemia, the Wright-stained peripheral blood smear will reveal microcytic, hypochromic red blood cells. In multiple myeloma the peripheral blood smears commonly have rouleuax formation. No other red blood cell abnormalities are typically noted. Question Difficulty: Level 9

Which of these processes would be characteristic of "Lean" laboratory production? Hold routine specimens in the specimen processing area until all phlebotomists have completed their morning rounds. Process and deliver patient samples to the testing areas in batches. Load patient samples onto automated analyzers as the samples arrive to the work area. Techs constantly leaving their workstation to locate regularly used supplies for their bench.

Load patient samples onto automated analyzers as the samples arrive to the work area. Lean is aimed at the elimination of waste in every work area of the laboratory. In a lean laboratory, specimens are processed as they arrive rather than waiting to process specimens at one time. Specimens should not accumulate in the processing area and batch testing is discouraged in Lean environments. Question Difficulty: Level 9

Which of the following substances produced by Group A Streptococci is responsible for producing type specific immunity? Streptolysin O Streptolysin S M antigen T antigen

M antigen The correct answer is M antigen The M antigen (also known as M protein) is also the major virulence factor of group A beta hemolytic streptococci. It prevents phagocytosis of the organism. Although antibodies to the M protein confer lifelong immunity, there are over 60 different M proteins, so recurrent S. pyogenes infections can easily occur in a given individual. Streptolysin O lyses leukocytes, platelets and RBCs. It is highly immunogenic and antibodies are formed quickly upon exposure. Streptolysin S also lyses leukocytes, but it is nonimmunogenic. T antigen is not an antigen associated with group A beta hemolytic streptococci. Question Difficulty: Level 7

All of the following colony and microscopic descriptions are paired correctly with the mold indicated, EXCEPT: Macroscopic description: rose red or purple red pigmentation Microscopic description: multi-celled, sickle shaped macroconidia Fusarium sp. Macroscopic description: grayish-brown colonies Microscopic description: Dark, elliptical conidia each supported by a conidiophore ("lollipops") Scedosporium apiospermum Macroscopic description: green, granular, rugose colonies Microscopic description: chains of spherical conidia produced from branching phialides Aspergillus sp. Macroscopic description: green lawn that extends from edge to edge Microscopic description: tight clusters of spherical conidia held by finger-like phialides Gliocladium sp.

Macroscopic description: green, granular, rugose colonies Microscopic description: chains of spherical conidia produced from branching phialides Aspergillus sp. The correct answer is macroscopic description: green, granular, rugose colonies; microscopic description: chains of spherical conidia produced from branching phialides; Aspergillus sp. "Chains of spherical conidia produced from branching phialides" is descriptive of Penicillium species, which typically produces green, granular, rugose colonies. "Multi-celled, sickle shaped macroconidia" is the description for Fusarium species, which produces colonies with a distinctive rose red or purple red pigmentation. "Dark, elliptical conidia each supported by a conidiophore ('lollipops')" is characteristic of Scedosporium apiospermum. The grayish-brown appearance is typical macroscopic morphology. The description of "tight clusters of spherical conidia held by finger-like phialides" is the microscopic description for Gliocladium, the colony of which typically appears as a "green lawn" that extends from border to border across the Petri dish. Question Difficulty: Level 7

In cases where more severe symptoms may occur, particularly in progressive anemia, what additional test procedure should be performed to determine the role that hookworm infection may play when ova are detected in stool specimens? Prepare permanent-stained mounts Prepare an acid-fast stained mount Make a quantitative count of the number of ova present Perform immunologic assays to detect Hookworm antigen in stool

Make a quantitative count of the number of ova present Make a quantitative count of the number of ova present is the correct response. Increased egg counts of 20/mg or more are associated with symptoms indicative of heavy worm burdens. Egg counts of 5/mg are rarely associated with symptoms. The diagnosis of hookworm infection relies on detecting eggs in the patient's stool. Identifying hookworm antigen will not provide an adequate determination of the entire worm burden. Eggs are typically detected by direct smear or concentration of the stool specimen. Stained preparations tend to distort the morphology of the ova; hookworm ova are not acid-fast. Diagnosis may also be made by radiographic studies to detect intestinal hypermotility, proximal jejunal dilatation and coarsening of the mucosal folds. Question Difficulty: Level 9

In which of the following conditions are Cabot rings most likely to be observed on a Wright-stained peripheral blood smear? Megaloblastic anemia Moderate iron deficiency anemia Sickle cell trait Plasma cell myeloma

Megaloblastic anemia Cabot rings have been observed in megaloblastic anemia, myelodysplastic syndromes, and other cases of dyserythropoiesis and severe anemia. They are not associated with moderate iron deficiency anemia, sickle cell trait, or multiple myeloma. Well-developed iron deficiency presents with microcytic, hypochromic red blood cells. Anisocytosis is a common finding which should correlate with an increased RDW on the CBC. Poikilocytes seen are target cells, elliptocytes, and teardrop cells. Sickle cell trait presents with normal red blood cell morphology; red blood cell inclusions are not seen. The main red blood cell morphology seen in plasma cell myeloma is rouleaux formation due to increased plasma immunoglobulin concentrations. Question Difficulty: Level 7

The following is a systemic, dimorphic genus that characteristically produces barrel-shaped arthroconidia separated by dysjunctor cells: Coccidiodes immitus Geotrichum species Trichosporon species Microsporum species

Microsporum species The mold form of Coccidioides immitusproduces barrel-shaped arthroconidia with alternate staining due to the presence of dysjunctor cells which are non-viable cells. This organism is the causative agent of coccidioidomycosis which is found primarily in the desert region of southwestern United States as well as the arid region of Mexico and Central and South America. TheGeotrichum species produce rectangular-shaped arthroconidia; however, they are regularly rather than alternately staining. Additionally, the arthroconidia of Geotrichum may produce germ tubes from one corner Trichosporon species produce rectangular-shaped arthroconidia; however, they are regularly rather than alternately staining. Additionally, the arthroconidia of Trichosporon species may produce blastoconidia from adjacent corners, features not shared by either Malbranchia species or s. The Microsporumspecies may produce arthroconidia; however, they are much narrower in dimension and do not share the alternate staining characteristics. This genus is more noted for producing multicelled macroconidia that are spindle-shaped. Question Difficulty: Level 8

Scedosporium Scedosporium is the correct selection. The "house-mouse" gray pigmentation of the colony is suggestive of Scedosporium species. This presumptive identification is confirmed by observing microscopically the small, spherical to oval dark gray conidia each at the tip of a delicate slender conidiophore. Conidiophores with a straight base, as presented in this exercise, is characteristic of Scedosporium apiospermum in contrast to the urn-shaped swelling at the base of the condidiophores of Scedosporium prolificans. Chrysosporium colonies also are not distinctive, growing in 2 - 4 days with a gray, wooly surface. Microscopically spherical, sub-globose to pyriform conidia are borne singly rather than in clusters at the tips of long thin conidiophores, simulating a "lollipop". Sepedonium colonies are gray white with a cottony surface that is non-specific. Microscopically, large spherical, bluntly spiked macroconidia are borne singly and not in clusters from long, delicate conidiophores. Beauveria colonies have a non-distinctive delicate silky, light gray-white surface mycelium. Key to the identification is the observation of small, spherical microconidia produced in loose clusters from delicate conidiophores with a zig-zag ("geniculate") bent knee effect. Question Difficulty: Level 1

Multiple young 3-day old colonies having a low cottony surface mycelium that upon maturity develop a distinctly gray pigmentation (referred to as "house mouse gray"). The reverse of the colony remains light gray in color and does not show the darker pigmentation. Microscopic examination of a small inoculums from the surfaces of the colony is illustrated in the lower photomicrograph. From the list of multiple choices, select the genus name of the fungus being presented. Beauveria Sepedonium Chrysosporium Scedosporium

All of the following are characteristic of Burkholderia pseudomallei EXCEPT? Has been reported as the cause of laboratory-acquired infection Oxidase positive Non-motile Catalase positive

Non-motile The correct answer is non-motile. B. pseudomallei is motile, a characteristic that differentiates it from the non-motile B. mallei. Burkholderia species is a dangerous and highly virulent organism that can cause laboratory-acquired infections. It should NOT be manipulated on an open bench. B. pseudomallei is oxidase positive, while B. mallei is oxidase variable. Both organisms are catalase positive and testing MUST be performed with extreme caution in a biosafety cabinet (BSC) due to the creation of aerosols. B. pseudomallei causes melioidosis, which is a glandular disease in animals and humans. It is found in the soil and stagnant water of primarily in Thailand, Vietnam, and parts of northern Australia. Question Difficulty: Level 7

Sideroblastic anemia The iron staining particles surrounding the nucleus of red blood cells create ringed sideroblasts. Iron has accumulated in mitochondria of erythroblasts; the mitochondria are located close to the nucleus, giving the ringed appearance. Primary sideroblastic anemia may be a component of neoplastic myelodysplasia. Ringed sideroblasts may also appear in impaired production of protoporphyrin following drug toxicities, chronic alcoholism, lead poisoning, and the use of certain antibiotics, particularly chloramphenicol. Conditions of defective globin synthesis, including thalassemia, may promote sideroblast formation as well. Although the red cells in sideroblastic anemia are hypochromic, this condition is not an iron deficiency. Bone marrow iron deposits are actually overabundant in a sideroblastic anemia; impaired production of protoporphyrin or defective insertion of iron into protoporhyrin causes decreased heme production so that iron accumulates in mitochondria. Patients with sickle cell anemia can sometimes have high plasma iron levels due to hemolysis and frequent transfusions. However, their developing red cells do not have any problems incorporating iron into the heme ring. Megaloblastic anemia involves a deficiency in either vitamin B12 or folate, and iron levels and utilization are usually normal. Question Difficulty: Level 2

Note the iron-stained bone marrow preparation in the image to the right. The cells as shown can be associated with which type of anemia? Iron deficiency anemia Sickle cell anemia Sideroblastic anemia Megaloblastic anemia

The following steps were used in a procedure to identify M. kansasii: 1 - Extraction 2 - Denaturization 3 - Hybridization 4 - Hydrolysis of excess reagent 5 - Detection of acridinium ester Which of the following methods has been described? Polymerase chain reaction Indirect fluorescent microscopy Nucleic acid probes Lysis-centrifugation

Nucleic acid probes The correct response is nucleic acid probes. The steps listed are included within the nucleic acid probes procedure for M. kansasii. The correct sequence for nucleic acid probes is extraction, denaturization, hybridization, hydrolysis of excess reagent, and detection of acridinium ester. In polymerase chain reaction, a small segment of DNA is expanded by binding DNA primers to segments at the ends of the DNA to be expanded. Thermal cycling creates single stranded DNA followed by cooling that enables the primers to anneal to the target DNA. This is followed by primer extension, where DNA synthesis occurs by forming a copy of the template DNA by adding nucleotides to the hybridized probe. Indirect fluorescent microscopy is used to detect antigens or antibodies. To detect antigen, the specimen is fixed onto a slide and an unlabeled antibody directed against the microorganism to be detected is added to the slide and permitted to react. After incubation, unbound antibody is washed away, and a second fluorescein-labeled antibody is added which will complex with the first antibody that has bound to the antigen. To detect antibody, antigens of the microorganism are fixed onto a microscope slide and the specimen added to the slide. After incubation, excess antibody is washed away and a fluorescein labeled conjugate added. Fluorescence indicates a positive reaction. Lysis centrifugation is used in some blood culture systems to enhance the recovery of bacteria and some fungi from blood cultures. Saponin is used to lyse the red cells and then the blood is centrifuged. The sediment is vortexed, and the entire sediment is plated onto agar. Lysis centrifugation can provide more rapid recovery and isolation from blood cultures. Question Difficulty: Level 7

Myeloid precursors predominant Myeloid precursors are NOT predominant on this slide. This is a trilinear bone marrow with an erythroid predominance (erythroid hyperplasia). This causes an inverted M:E ratio; meaning there are more erythroid precursors then myeloid precursors present. The normal M:E ratio is 1.5 to 3.1 myeloid cells per erythroid cell. The large cell in the lower left portion of the image is a megakaryocyte. Question Difficulty: Level 7

Observe the bone marrow sample in the image to the right. All of the descriptors below apply EXCEPT? Myeloid precursors predominant Inverted M:E ratio - around 1:3 Megakaryocyte present Erythroid hyperplasia is present

Drepanocyte Drepanocytes, or sickle cells are not visible in this smear. Sickle cells are half-moon shaped cells with pointy ends. Burr cells, with short projections on their periphery are in this image. Several target cells or codocytes, with their characteristic dark centers surrounded by an area of pallor are seen. A few spherocytes, which are small deeply staining cells with no pale area, are also seen. Other poikilocytes visible are schistocytes and acanthocytes. This image is possibly of a smear from a post-splenectomy patient. Question Difficulty: Level 5

Observe the peripheral blood smear image to the right. Several types of poikilocytes are seen. All of the following are seen in the image EXCEPT? Drepanocyte Burr cell Target cell Spherocyte

Which of the following is the first step in the four steps of Koch's postulates? Organism must be isolated and grown from the infected host Organism, from pure culture, must reproduce the disease in an inoculated host Organism must be isolated in pure culture from experimentally infected host Observe the same organism in all cases of a given disease

Observe the same organism in all cases of a given disease Observe the same organism in all cases of a given disease is the correct answer because based on Koch's postulates, the first postulate states, "The same organism must be found in all cases of a given disease." Organism must be isolated and grown from the infected host is incorrect because this is the second step in Koch's postulates that states, "The organism must be isolated and grown in pure culture from the infected host." Organism, from pure culture, must reproduce the disease in an inoculated host is incorrect because this is the third postulate that states, "The organism, from pure culture, must reproduce the disease when inoculated into a susceptible animal." Organism must be isolated in pure culture from experimentally infected host is incorrect because this is the last of Koch's postulates that states, "The organism must be isolated in pure culture from an experimentally infected animal." Question Difficulty: Level 8

Rhinocladiella sporulation Rhinocladiella sporulation is the correct response. Conidia are produced singly, directly, and laterally in compact rows from the sides of the hyphae. This form of sporulation is commonly observed as one of the identifying forms produced by certain strains of Fonsecaea pedrosoi. Acrotheca sporulation is characterized by sympodial branches of conidiophores that are produced from the tips of septate hyphae, simulating the prongs of a coat rack. Elliptical conidia in short chains are produced from the tips of these branching conidiophores. Cladosporium sporulation presents long straight chains of elliptical, dark-staining conidia each separated by a delicate scar known as a dysjunctor. Phialophora sporulation is in the form of short urn-shaped phialides each with a narrow bottle-like opening from which oval-shaped, yellow pigmented conidia are produced from within each phialide, forming loose aggregates at the terminal opening. Question Difficulty: Level 1

Observed in the image is the microscopic appearance of a sporulation representative of one of the dematiaceous fungi causing chromomycosis. Note that spherical conidia are being produced laterally from the sides of a conidiophore. Which of the following choices represents the type of sporulation illustrated in this image? Rhinocladiella sporulation Acrotheca sporulation Cladosporium sporulation Phialophora sporulation

Scopulariopsis Scopulariopsis is the correct selection. The colonies are characteristically yellow-brown to buff with a finely granular surface, with radial rugae emanating from the center to the periphery. The identification of Scopulariopsis spp. can be made microscopically from observation of the size and morphology of the conidia. The conidia are two to three times larger than those of Penicillium spp. and Paecilomyces spp., and are spherical, except for the presence of a distinct flat or truncated base. They are arranged in chains, with the truncated base of each successive conidia attached to the round terminus of the previous conidium. Paceliomyces and Penicillium colonies are blue-green. Microscopically the conidia are relatively small, spherical and arranged in chains, derived from branching phialedes. The phialides of Paecilomyces are long with a sharp pointed end; those of Penicillium are short with a distinctive flat surface connected to the chains of conidia. Fusarium colonies are lavender or rose-red with pigment extending into the surrounding agar. Distinctive is the production of long canoe-shaped, multi-celled macroconidia with a terminal hair-like "foot cell" extension from one end. Question Difficulty: Level 1

Observed in the upper image is a yellow-brown colony growing on Sabouraud's Dextrose agar after 72 hours incubation at 30oC, as recovered from a subcutaneous abscess following a traumatic injury in an immune-compromised host. The microscopic appearance is shown in the lower image, revealing relatively large conidia arranged in long chains. Based on these features, select the fungus genus name from the multiple choices. Paecilomyces Fusarium Scopulariopsis Penicillium

Which one of the following conditions is associated with glucose-6-phosphate dehydrogenase (G6PD) deficiency? Microcytic red cells Precipitation of hemoglobin Faulty heme synthesis Hemoglobins with low oxygen affinities

Precipitation of hemoglobin G6PD deficiency inhibits the erythrocyte's ability to detoxify oxidative compounds. When these oxidative compounds increase, they oxidize hemoglobin into a less soluble form which precipitates within the cell. We can visualize this precipitated hemoglobin derivative as Heinz bodies. Microcytic cells are not associated with G6PD deficiency. Hemolytic anemias, such as G6PD deficiency, are usually normocytic and normochromic. G6PD deficiency is not associated with faulty heme synthesis. In contrast, patients with G6PD deficiency are unable to produce enough NADPH in the hexose monophosphate shunt. This ultimately impairs the erythrocyte's ability to protect itself against oxidative compounds such as hydrogen peroxide G6PD deficiency is not associated with alternative forms of hemoglobin with low oxygen affinities. The Heinz bodies are the products formed after the erythrocyte's hemoglobin has been oxidized. Question Difficulty: Level 7

Which of the following laboratory results would you find with disseminated intravascular coagulation (DIC) but NOT with thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS)? Prolonged PT and aPTT Thrombocytopenia Schistocytes on the peripheral blood smear Elevated LDH

Prolonged PT and aPTT Thrombocytopenia, schistocytes and elevated LDH are also associated with TTP and HUS; it is the abnormal coagulation tests that distinguish DIC from these other conditions. Disseminated intravascular coagulation (DIC) is a condition that results in consumption of coagulation factors, platelets and the formation of fibrin degradation products. Schistocytes are produced as blood cells are forced through the fibrin webs that clog the microvessels. Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) present with microangiopathic anemia, thrombocytopenia, and microvascular thrombotic lesions. The pathophysiology of TTP is systemic platelet agglutination . HUS clinical findings are thrombocytopenia and neurologic manifestations. It is closely associated with infection by verotoxin-producing E. coli. In TTP and HUS, the PT and aPTT are usually normal. DIC, TTP, and HUS present with microangiopathic hemolytic anemia, and therefore schistocytes and elevated LDH. Question Difficulty: Level 7

Which of the following laboratory results would you find with disseminated intravascular coagulation (DIC) but NOT with thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS)? Prolonged PT and aPTT Thrombocytopenia Schistocytes on the peripheral blood smear Elevated LDH

Prolonged PT and aPTT Thrombocytopenia, schistocytes and elevated LDH are also associated with TTP and HUS; it is the abnormal coagulation tests that distinguish DIC from these other conditions. Disseminated intravascular coagulation (DIC) is a condition that results in consumption of coagulation factors, platelets and the formation of fibrin degradation products. Schistocytes are produced as blood cells are forced through the fibrin webs that clog the microvessels. Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) present with microangiopathic anemia, thrombocytopenia, and microvascular thrombotic lesions. The pathophysiology of TTP is systemic platelet agglutination . HUS clinical findings are thrombocytopenia and neurologic manifestations. It is closely associated with infection by verotoxin-producing E. coli. In TTP and HUS, the PT and aPTT are usually normal. DIC, TTP, and HUS present with microangiopathic hemolytic anemia, and therefore schistocytes and elevated LDH. Question Difficulty: Level 7

Which of the following statements is true regarding primary hemostatic process resulting from vascular damage? Inhibition of platelet function by interaction with collagen. Platelet adhesion through Weibel-Palade bodies. Platelet aggregation through interaction of von Willebrand factor and glycoprotein IIb/IIIa. Rapid and immediate vasoconstriction by contraction of smooth muscles.

Rapid and immediate vasoconstriction by contraction of smooth muscles. Rapid vascular constriction, not dilation, immediately occurs when there is vascular injury in order to constrict the amount of blood that escapes the vessels; ultimately preventing massive loss of blood. Collagen is a powerful stimulator of platelet aggregation. Platelet adhesion occurs by von Willebrand factors (produced in Weibel-Palade bodies) bridging glycoprotein Ib and the exposed collagen. Platelet aggregation requires fibrinogen and glycoprotein IIb/IIIa. Question Difficulty: Level 7

You are working in a hematology laboratory and the machine flags an outlier result for a 51-year-old male. The blood was collected in an EDTA tube for a CBC. The hematocrit of the specimen is high at 60%. Which of the following would you do? Collect blood again, but use less sodium citrate in the tube Collect blood in heparin Report these results Assume that the specimen was switched with that of a newborn child

Report these results The correct answer is: report these results There may be several reasons for a high hematocrit - including the obvious possibility that this is a newborn (normal hematocrit range of 55-68%). Another likely reason for a high hematocrit is dehydration - the individual just happens to have less fluid in the body. Less frequent causes include Polycythemia Vera or high hematocrit due to blood doping. The first choice, "collect blood again, but use less sodium citrate in the tube" is wrong for two reasons: (1) you use EDTA rather than sodium citrate for CBC blood collection and (2) blood collection is a standardized practice and thus your goal in testing the hematocrit is to determine the actual hematocrit - not to artificially disturb the ratio of anticoagulant in order to arrive at a normalized determination of hematocrit. The second choice, "collect blood in heparin" is wrong because you don't collect CBC specimens in heparin - you use EDTA. While it is true that this hematocrit falls within the normal range of a newborn, 60% is not so tremendously high (normal hematocrit for an adult male is 42-52%) that you ought to assume that specimens have been switched. Question Difficulty: Level 9

An alpha hemolytic slightly concave isolate from a respiratory specimen gave a zone of inhibition of 18 mm around the optochin disk. What should the next step be? Report the isolate as optochin sensitive. Report this organism as Streptococcus pneumoniae. Report this organism as Viridans streptococci. Repeat the optochin susceptibility test.

Report this organism as Streptococcus pneumoniae. The correct answer is to report this organism as Streptococcus pneumoniae. Streptococcus pneumoniae is susceptible to optochin, where all other alpha hemolytic streptococcus species are resistant. A zone measuring greater than or equal to 16 mm is considered susceptible. Streptococcus pneumoniae is a virulent pathogen, mainly due to its capsular polysaccharides. Streptococcus pneumoniae strains that lose the ability to produce a capsule are nonpathogenic. Optochin disks are used for identification, not antimicrobial susceptibility testing. With a susceptible optochin result, this isolate is not a Viridans streptococci. There is no need to repeat the optochin susceptibility, as this zone is sufficient for interpretation. Question Difficulty: Level 7

Which of the following statements are true for the hematopoietic cords? Hematopoietic cells develop at random locations in the marrow cells Reticular cells (adventitial cells) provide support for developing hematopoietic cells Lymphocytes are not seen in normal marrow Fat cells content of bone marrow decrease with aging

Reticular cells (adventitial cells) provide support for developing hematopoietic cells Reticular cells (adventitial cells) provide structural support for the endothelial cells that line the venous sinus and the developing blood cells within the hematopoietic cord. The cytoplasm of the reticular cells is capable of extending itself in fiberlike strands deep into the hematopoietic cords. These strands provide a meshwork for the blood cells. Other types of cells which furnish support in the cord include macrophages and fat cells. Within the hematopoietic cords each cell line has a specific location for development. Like any other blood cell lineage, lymphocytes also arise from pluripotential hematopoietic stem cell found in the bone marrow. Fat cell content increases with age, and the average adult has about 50% fat cells (adipose cells) that make up the volume of their bone marrow. Question Difficulty: Level 7

Cholera The correct answer is Cholera. Although each of the diseases mentioned in this exercise cause diarrheal syndromes, and each has been present for centuries, the description of rice water stools and the appearance of the sucrose positive colonies on the thiosulfate citrate bile sucrose agar shown in the photograph points to Vibrio cholerae and cholera as the correct answer. Epidemics of Asiatic cholera have always followed large migrations of people, including journeys to Mecca, the influx of Irish settlers into Canada and the occupation of the gold fields in California. Lack of sanitation, uncontrolled elimination of human excreta and sharing of contaminated public water supplies were all common predisposing conditions. The diarrhea of typhoid fever is bloody and purulent and not rice water in type. Shigella species do not ferment sucrose and Campylobacter species do not grow on TCBS agar. Question Difficulty: Level 2

Rice water stools that are most commonly due to ingestion of contaminated water and have been a major public health concern for centuries exhibit colonies on TCBS agar consistent with those in the image to the right are caused by a condition called: Cholera Typhoid fever Shigellosis Campylobacterosis

Which of the following is/are NOT associated with immediate hypersensitivity? Hay fever Serum sickness Arthus reaction Anaphylactic shock Tuberculin reaction

Serum sickness Arthus reaction Tuberculin reaction The tuberculin reaction is a type of delayed hypersensitivity reaction that appears 48-72 hours after antigen exposure, which is different from an immediate hypersensitivity response, which generally appears within 12 minutes of an antigen challenge. Arthus reactions and serum sickness are classified as a Type III hypersensitivty reactions involving the formation of immune complexes. The other choices above are all associated with immediate hypersensitivity reactions. Question Difficulty: Level 7

Mycobacterium abscessus The outbreak described in the clinical history indeed was caused by Mycobacterium abscessus, a rapidly growing species of the mycobacterium. The pale staining acid fast smear and rapid growth of smooth, yellow-white colonies are consistent findings. This species of mycobacteria is known to cause skin and soft tissue infections as well as disseminated disease in immunocompromised hosts. Mycobacterium marinum causes subcutaneous infections; however, does not grow at 35°C, showing optimal growth at 30°C, Nocardia species also causes subcutaneous infections; however, Nocardia species are only partially acid fast and appears as branching, fine filaments with fragmentation in direct smears. Colonies are typically wrinkled and dry with a pigment ranging from chalky-white to tan or orange. Streptomyces species may rarely cause subcutaneous infections; however, are not acid fast and exhibit extensive branching filaments with spores and chains. Colonies are typically waxy and heaped or glabrous. Question Difficulty: Level 5

Several patients developed subcutaneous abscesses at the sites of injection of a preparation labeled "adrenal cortex injection" administered as part of a weight loss regimen. Pale-staining, filamentous acid-fast bacilli were seen in the material aspirated from the lesions (the upper photomicrograph is representative) and the colonies shown in the lower photograph grew out after 3 days incubation at 35°C in CO2. The most likely identification is: Mycobacterium marinum Mycobacterium abscessus Nocardia otitidiscaviarum (caviae) Streptomyces somaliensis

All of the following organisms can exhibit beta hemolysis, EXCEPT: Streptococcus anginosus Enterococcus faecalis Escherichia coli Shigella sp.

Shigella sp. The correct answer is Shigella sp. Shigella sp. are not known to be beta hemolytic, which helps to differentiate them from E.coli. Streptococcus anginosus is usually beta, but may be alpha or gamma hemolytic. One additional clue to the identification of S. anginosus is the detection of a distinct butterscotch odor. Enterococcus faecalis is typically alpha hemolytic, but may be beta or gamma hemolytic. Additional biochemical testing is often required to differentiate these organisms from viridans streptococci. Escherichia coli is found with beta, alpha, or gamma hemolysis. It is indole positive and motile, which also help to differentiate it from Shigella sp. Question Difficulty: Level 8

Proteus mirabilis KIA contains glucose and lactose to detect fermentation, and an H2S indicator. Inoculated medium should be read after incubation for 18-24 hours. Proteus mirabilis is the correct response. The tube indicates abundant H2S production *********** of the tube along with glucose fermentation, reactions characteristic for P. mirabilis. The red alkaline slant indicates the lack of lactose fermentation that precludes H2S production in this part of the tube. The KIA reaction for this species would be read as "K/A H2S." Enterobacter cloacae, Klebsiella oxytoca, and Escherichia coli are among the lactose-fermenting Enterobacteriaceae that produce an acid/acid reaction on Kligler Iron Agar (KIA) without black pigmentation, as H2S is not produced by any of these species. KIA reactions for these species would be read as "A/A." Question Difficulty: Level 9

Shown here is a Kligler Iron Agar (KIA) tube with black pigmentation is confined to the butt of the tube. From the multiple choices, select the bacterial species that produces the reaction seen in the lower image of the KIA tube. Proteus mirabilis Enterobacter cloacae Klebsiella oxytoca Escherichia coli

Neisseria meningitidis Neisseria meningitidis is the correct response. The intra-cellular small gram-negative cocci as observed in the sediment of spinal fluid, as presented in the photomicrograph, are consistent with a presumptive identification of Neisseria species. The observation of these intracellular cocci in a spinal fluid sediment would further suggest Neisseria meningitides. This presumptive identification can be confirmed by demonstrating the selective carbohydrate utilization of both glucose and maltose as observed by the yellow pigmented tube reactions. Direct capsular antigen tests and molecular assays are also available for the rapid identification of Neisseria meningitidis. Children and adults may carry N. meningitidis bacteria in the oropharynx, that can potentially spread to the meninges and the brain from dissemination of oropharyngeal infections. Neisseria gonorrhoeae colonies and the appearance of intracellular gram-negative cocci in gram stains are similar to those of M. meningitides. Distinctive for N. gonorrhoeae is the selective utilization of glucose, with maltose fermentation being negative. The source of the infection being in the genitourinary and reproductive sites would also be discriminatory. Aeromonas species colonies are small, opaque, gray white and beta hemolytic on blood agar. Colonies growing on MacConkey agar are entire, smooth, and pink indicating lactose fermentation. Bacilli instead of cocci are observed in gram stains. Distinctive is the production of acid also from sucrose and lactose in addition to glucose and maltose. Infections associated with skin wounds and lacerations exposed in water sports, and septicemia are commonly associated with Aeromonas species. Kingella kingae colonies grow well on blood agar with distinctive soft beta hemolysis. Short, plump, gram-negative cocco-bacillli in pairs and short chains are observed in gram stains. Acid is produced selectively from glucose and maltose in addition to other carbohydrates. Other biochemical characteristics or antigen tests may be required to make a definitive identification. Distinctive from Neisseria species, the catalase reaction for K. kingae is negative. Question Difficulty: Level 1

Small intracellular gram-negative cocci were observed in a centrifuged spinal fluid sediment as presented in the upper photomicrograph. A clinical diagnosis of meningitis was suspected. Yellow-gray colonies after 24-hour incubation had been observed on blood agar. Based on the carbohydrate utilization tube reactions observed in the lower photograph, select from the multiple choices the presumptive identification of this isolate. Neisseria gonorrhoeae Neisseria meningitidis Aeromonas species Kingella kingae

Lactobacillus species Lactobacillus species are aerotolerant anaerobes. The colonies growing on sheep blood agar after 24 hours incubation are gray white, convex, smooth and non-discriminatory. Observation of narrow zones of light alpha hemolysis would help to make a presumptive identification. The microscopic observation of long, slender, non-spore forming gram-positive bacilli arranged in short and long chains is characteristic. Additional assays may be required to confirm the identification. Actinomyces species colonies may vary in texture and color. Actinomyces species are aerotolerant anaerobes. Actinomyces species are gram-positive, non-spore-forming bacilli that may be filamentous, beaded, or branching. Rothia dentocariosa is a gram-positive bacilli or cocco-bacilli observed in diphtheroidal arrangements. Filamentous forms are seen in older cultures. Hemolysis is not observed. Corynebacterium striatum colonies are relatively small, convex, smooth, and non-hemolytic. Small club-shaped, gram-positive bacilli are in small clusters or in picket fence or Chinese letter arrangements are observed in Gram stains. Question Difficulty: Level 5

Small, smooth, gray-white, 24-hour colonies are seen growing on the surface of sheep blood agar with faint alpha-hemolysis. This isolate is most often part of the normal flora, serving in several body sites as a protection against harmful bacteria through production of lactic acid. The gram stain reveals long, slender gram-positive bacilli lying singly and in short chains. It is a non-branching, non-spore-former. From the multiple choices, select the presumptive identification of this isolate. Actinomyces species Rothia dentocariosa Corynebacterium striatum Lactobacillus species

The dimorphic fungi that may produce black, yeast-like colonies after prolonged incubation at 37°C is: Blastomyces dermatitidis Paracoccidioides brasiliensis Sporothrix schenckii Histoplasma capsulatum

Sporothrix schenckii The correct answer is Sporothrix schenckii. The mold colonies of Sporothrix schenckii grown at 22°C are initially moist and glabrous, almost yeast-like, but growing darker and more mycelial as they mature. At 37°C, yeast conversion of the colonies occurs, and pigmentation may vary from brown to brown-black to jet black. Thus, S. schenckii must be included in the differential identification when an unknown fungus appears as a black yeast. The mold colonies of B. dermatitidis, P. brasiliensis, and H. capsulatum can be converted to yeast forms by incubating subcultures on enriched media at 37°C. The converted yeast colonies, however, remain gray-white, yellow-white, or yellow and never develop a dark brown or black pigmentation. Question Difficulty: Level 7

Which of the following is LEAST likely to stimulate the production of reactive lymphocytes? Staphylococcus aureus Cytomegalovirus (CMV) Epstein-Barr virus Toxoplasma gondii

Staphylococcus aureus Cytomegalovirus (CMV), Epstein-Barr virus (EBV), and Toxoplasma gondii are all infectious diseases which lead to lymphocytosis in the infected patient, often with stimulated (reactive) lymphocytes visible upon a manual WBC differential. Staphylococcus aureus is a bacterial infection that can cause elevated WBC counts (due to increased numbers of neutrophils) but reactive lymphocytes are not typically seen. Question Difficulty: Level 7

Each of the bacterial species listed below may be associated with culture-negative endocarditis EXCEPT: Cardiobacterium hominis Streptococcus abiotropha Brucella abortis Staphylococcus epidermidis

Staphylococcus epidermidis Culture negative endocarditis most commonly results from failure to recover a bacterial species that is either nutritionally demanding or has a rate of growth beyond the time in which blood culture bottles are incubated. Staphylococcos epidermidis is not an uncommon agent of endocarditis; however, it grows well in all culture broth media without the need for supplements; therefore, is the correct answer to this exercise. Cardiobacterium hominis and all Brucella species require a prolonged time of incubation, often 10-14 days or more. Blood cultures are commonly held only 5 or no longer than 7 days in most clinical laboratories. Streptococcus abiotropha ("nutritionally variant" or pyridoxyl dependent "streptococci") have an absolute requirement of pyridoxyl and may not be recovered in blood cultures unless the medium is supplemented with pyridoxyl or cysteine. Question Difficulty: Level 7

Match the following test principles with the most appropriate response: Signal amplification using alkaline phosphatase and thermal cycling Target amplification using reverse transcriptase. No thermal cycling is needed. Target amplification using DNA polymerase and no thermal cycling Target amplification using 2 enzymes and no thermal cycling

Target amplification using reverse transcriptase. No thermal cycling is needed. TMA- Target amplification using reverse transcriptase. No thermal cycling is needed. PCR- Target amplification using DNA polymerase and thermal cycling bDNA- Signal amplification using alkaline phosphatase and no thermal cycling NASBA- Target amplification using 3 enzymes and no thermal cycling Question Difficulty: Level 9

Mycoplasma sp. The growth seen here is most likely Mycoplasma spp. PPLO agar contains nutrients provided by peptones, serum, and heart infusion. There is less agar added to the medium than other solid agar plates leaving the medium softer so that mycoplasmas can grow into the medium as opposed to mainly on top of the medium. Typical morphology of the small Mycoplasma spp. colonies is that of a "fried egg" appearance. Streptococcus pneumoniae and Klebsiella pneumoniae will both grow well on enriched nutrient media, such as sheep blood agar. S. pnuemoniae displays alpha hemolysis on this media and the colonies have a mucoid appearance with a concave center. K. pneumoniae colonies will have a moist, mucoid appearance when grown on nonselective media. The mucoid appearance of these organisms is due to the protective capsule they produce. Mycobacterium spp. are inoculated to media specifically formulated to optimize their growth. The three general types of media are egg-based, serum albumin, and liquid media. Colonies of mycobacteria may have a smooth or rough appearance but do not grow as dense centers with a less dense periphery or "fried egg" appearance. Question Difficulty: Level 5

The "fried egg-like" growth - colonies with dense centers surrounded by a less dense periphery - seen here on PPLO agar is most likely caused by: Streptococcus pneumoniae Klebsiella pneumoniae Mycobacterium sp. Mycoplasma sp.

Aspergillus fumigatus Aspergillus fumigatus is the correct response. Distinctive is the rapid growth of a blue-green, cottony colony with a narrow peripheral apron. The microscopic appearance is confirmatory with a distinctive single row of phialides atop a club-shaped swollen vesicle that covers the upper two-thirds of the vesicle with long rows of small, spherical conidia. Penicillium species colonies are also rapidly growing, with a green granular surface. The conidia also are produced in chains, but from an inner row of short branching metulae giving rise to the spore bearing phialides that end in a flat surface. Paecilomyces species colonies have a light yellow-brown pastel pigmentation. Microscopically, chains of irregular sized, uneven staining conidia are produced from long and slender pointed phialides. Aspergillus terreus colonies are similar in form to those of A. fumigatus, but with a distinctly yellow pigmentation. The fruiting head is in the form of a club-shaped swollen vesicle, but is distinctive with a double row of broad phialides with conidia being produced from the outer row. Question Difficulty: Level 1

The 4 day growth of colonies on Sabouraud's dextrose agar, as shown in the upper image, was recovered from the alveolar lavage of a 45 year-old construction worker who presented with X-ray evidence of a lung abscess. The light green colony in the upper image, with a cottony surface, shallow rugae, and a white surrounding apron was recovered on Sabouraud's dextrose agar from an induced sputum sample after 4 days incubation at 30° C. The Lacto-phenol cotton blue stain microscopic appearance from the surface colony is illustrated in the lower image. From these observations select the fungal species. Penicillium species Aspergillus fumigatus Paecilomyces species Aspergillus terreus

Clostridium septicum The bacterial cells are bacillary and gram variable. Both aerobic and anaerobic bacilli have a propensity to easily over decolorize in the Gram stain; a mixed field of gram-positive and gram-negative cells, as shown in the image, is often seen. The presence of spores rules out Clostridium perfringens, which virtually never produces spores in clinical infections. Lactobacillus rhamnosus is a non-spore-forming, gram-positive bacilli, rarely isolated in blood cultures. Although gram-negative appearing bacilli (over decolorized) are observed, presence of spores eliminates Bacteroides fragilis. By elimination, Clostridium septicum is the correct answer. Question Difficulty: Level 8

The Gram stain shown in the image was prepared from a positive anaerobic blood culture bottle after 36 hours incubation. Based on the morphology of the bacterial cells (some with spores, noted by the blue arrows), what is the most likely identification? Clostridium perfringens Clostridium septicum Lactobacillus rhamnosus Bacteroides fragilis

May-Hegglin anomaly May-Hegglin anomaly is a rare autosomal dominant condition in which patients are at risk for bleeding and infections. It is characterized by the presence of large Dohle body like inclusions within neutrophils, eosinophils, basophils, and monocytes. Alder-Reilly anomaly is a rare autosomal recessive disorder seen in patients with genetic mucopolysaccharidosis (Hurler's, Hunter's and Maroteaux-Lamy). It is characterized by the presence of purple-red particles that precipitate mucopolysaccharides in neutrophils, monocytes and lymphocytes. Pelger-Huet anomaly is seen in mature neutrophils that have a characteristic bilobed or dumbbell nuclei. Most patients with this anomaly have normal cell function and do not require treatment. Toxic granulation seen in band and segmented neutrophils or monocytes with prominent dark granulation, either fine or heavy. This is commonly caused by the precipitation of RNA caused by metabolic toxicity within the cells. Most frequently associated with infectious states, burns, and malignant disorders. Question Difficulty: Level 5

The WBC anomaly indicated by the arrow in this illustration is: Alder-Reilly anomaly Pelger-Huet anomaly May-Hegglin anomaly Toxic granulation

Clostridium perfringens The photograph of the agar plate illustrates a double zone of hemolysis around the colonies (blue arrows show the beta hemolytic zones, the yellow arrows the outer zone of lecithinase activity), characteristic of Clostridium perfringens. Necrotizing bowel disease, characterized by sudden onset of abdominal cramps, vomiting, bloody diarrhea and shock, occurs following ingestion of food heavily contaminated with enterotoxin-producing strains of Clostridium perfringens. Predisposing conditions include the consumption of excessive amounts of foods rich in trypsin inhibitors (sweet potatoes and peanuts). In New Guinea, the disease typically develops following consumption of large amounts of poorly cooked pork at pig feasts. Neither Fusobacterium mortiferum nor Bacteroides distasonis produce a double zone of hemolysis, and neither are associated with necrotizing bowel disease. Bacillus cereus does produce toxin-related enteritis; however, this organism is an aerobe and produces only a single zone of hemolysis on blood agar. Question Difficulty: Level 4

The anaerobe growing on the surface of the blood agar plate, the toxins of which cause a form of necrotizing enteritis known as Darmbrand ("fire bowels") in Germany or "Pig bel" in New Guinea, is: Fusobacterium mortiferum Bacteroides distasonis Clostridium perfringens Bacillus cereus

Lecithinase Lecithinase is the correct answer because the outer zone of hemolysis is due to an alpha toxin that hydrolyzes lecithin and sphingomyelin found in the cell membranes of red blood cells, platelets, and white blood cells. The alpha toxin acts on the erythrocytes in blood agar and breaks down the cells releasing lecithins into the medium. Egg yolk agar is often included in the battery of differential tests for the identification of anaerobes. Egg yolk is rich in lecithin, a phospholipid found in animal tissues. Clostridium perfringens actively produces lecithinase, which will break down lecithin to produce diglycerides resulting in an opaque, white halo around the colony. Cytotoxin A is incorrect because this toxin is produced by Clostridium difficile, resulting in superficial necrosis of the bowel mucosa and pseudomembrane formation. Beta hemolysin is incorrect because a beta hemolysin has the ability to cause complete lysis of red blood cells. Streptococcus pyogenes is a common organism that produces a beta hemolysin resulting in the complete destruction of red blood cells, which results in the production of a clear zone of hemolysis around the colony growth. Endotoxin is incorrect because endotoxins are typically found in Gram negative bacteria such as Enterobacteriaceae. This group of organisms has a lipopolysaccharide that makes up their structure and serves as an endotoxin. The lipopolysaccharide plays a role in the organism's pathogenesis, but the degree of toxicity will vary from one organism to another. Question Difficulty: Level 7

The anaerobe producing the double zone of hemolysis, seen in this photograph, can be presumptively identified as Clostridium perfringens. The enzyme producing the outer zone of hemolysis is: Cytotoxin A Beta hemolysin Lecithinase Endotoxin

Agglutination The red cells are arranged in small, irregularly distributed, grape-like clusters, representing agglutination. RBC clumping or agglutination associated with cold agglutinins (often IgM antibodies) is found in immune hemolytic anemias, in infections such as mycoplasma pneumonia, and in certain malignancies. Rouleaux formation appears as red blood cells that are linearly arranged simulating a stack of coins that may be short or long in length. Rouleaux formation related to increased plasma proteins, primarily fibrinogen or globulins, is found on peripheral smears in monoclonal gammopathies as multiple myeloma or Waldenstrom's macroglobulinemia. Normal distribution of red blood cells is found in the thin portion of the smear, where estimates and differentials are performed, when there is slight spacing between red blood cells and they are just starting to touch without overlapping. Aggregation is platelet-to-platelet interaction following shortly after vascular injury and platelet adhesion. This is not an abnormal distribution in red blood cells. Question Difficulty: Level 4

The arrangement of the erythrocytes shown by the blue arrows in this peripheral smear should be reported out as ____________________ . Agglutination Rouleaux Normal distribution Aggregation

Lymphocytes The arrows in Image B are pointing to lymphocytes. Chromatin is dense and the cells are normal in size. Question Difficulty: Level 1

The arrows in the images below indicate cells that may be observed in CSF samples. Match each image to the cell's identification. Choroidal cells Monomacrophages Presumptive malignant cells Lymphocytes

Helicobacter pylori Helicobacter pylori is the correct response. H. pylori is found only in the mucus-secreting epithelial cells of the stomach and has found to be the causative agent of chronic gastritis, leading to peptic ulcer disease and less commonly adenocarcinoma. H. pylori is a strong producer of urease from the abundant urea present in the gastric secretions. The urease is present in high concentrations and its presence is detected through the use of the urea breath test. To perform a urea breath test, a patient will ingest radioactive labeled urea and the bacterial urease will hydrolyze the urea to form ammonia and labeled bicarbonate that is exhaled as labeled CO2. The labeled CO2 will be measured to determine if H. pylori is present. The presence of abundant urease and along with X-ray evidence of peptic ulcer disease or carcinoma provides for a definitive diagnosis. Brucella species are small gram negative, facultative coccobacilli that are known to cause Brucellosis. This organism requires CO2 for growth and is a rapid urease producer. This organism is not found in the upper gastrointestinal tract; therefore, urease will not be present resulting in labeled CO2 in exhaled respiratory air leading to a negative urea breath test. Campylobacter jejuni is incorrect even though it is present in the upper gastrointestinal tract. This organism is urease negative; therefore, the urea breath test would be negative. Actinobacillus ureae is incorrect even though this organism is a strong producer of urease. This organism is not found in the upper gastrointestinal tract; therefore, urease will not be present resulting in labeled CO2 in exhaled respiratory air leading to a negative urea breath test. Question Difficulty: Level 1

The bacterial species presented here serves as the causative agent of active chronic gastritis of the lower pyloric antrum of the stomach with the complications of peptic ulcer disease and less commonly carcinoma. Small, curved, plump bacilli are seen on stains of tissue sections obtained from infected intestinal mucosa as illustrated in these photomicrographs. This ulcer and carcinoma producing bacterium can be presumptively identified by the use of the urea breath test in which strong urease produced by this bacterial species is detected by capturing radioactive labeled CO2 in the exhaled breath from an infected patient. From these observations, select the causative bacterial species. Brucella species Campylobacter jejuni Actinobacillus ureae Helicobacter pylori

Acute post-streptococcal glomerulonephritis The test shown in the photograph is a positive CAMP reaction. The arrow-shaped zone of accentuated beta hemolysis provides a presumptive identification of Streptococcus agalactiae (group B). This organism has been associated with neonatal meningitis, neonatal sepsis and soft tissue infections in adults. Acute post-streptococcal glomerulonephritis is associated with Streptococcus pyogenes (group A). Neonatal meningitis with Streptococcus agalactiae is a significant concern especially if preceded by the premature rupture of the mother's membranes. Approximately 10-30% of females carry this organism in the vaginal area with the higher percentile carrier rate occurring during pregnancy. Neonatal sepsis with Streptococcus agalactiae is a significant concern especially if preceded by the premature rupture of the mother's membranes. Approximately 10-30% of females carry this organism in the vaginal area with the higher percentile carrier rate occurring during pregnancy. Soft tissue infections in adults have been associated with Streptococcus agalactiae especially if the host is immunocompromised. Question Difficulty: Level 6

The bacterial species represented by the positive test illustrated in the photograph of a 5% sheep blood agar plate cross streaked with a hemolytic strain of Staphylococcus aureus has been associated with each of the following conditions except: Neonatal meningitis Neonatal sepsis Soft tissue infections Acute post-streptococcal glomerulonephritis

Superficial skin snip Superficial skin snip is the correct response. The scalp nodule illustrated in the photograph is characteristic of an onchocercoma caused by Onchocerca volvulus. This organism would only be suspected in the right clinical setting. The diagnosis is best confirmed by using the skin snip preparation for microscopic exam as the microfilaria tend to invade the superficial subcutaneous skin. Open surgical biopsy is incorrect. The microfilaria in Onchocerca infections are located in the superficial subcutaneous layers of skin. As the superficial skin is often scraped and sanitized prior to biopsy, the infective microfilaria may not be included. Aspiration biopsy is incorrect. As the aspiration needle is most often inserted deep into the lesion, Onchocerca microfilaria may be missed as they tend to occupy the more superficial skin. Surface skin scraping is incorrect. Although the Onchocerca microfilaria typically occupy the superficial subcutaneous tissue of the skin, they may not be observed in the more superficial surface skin scraping samples. Question Difficulty: Level 9

The best sample to obtain in order to diagnosis the parasite causing the posterior scalp nodule as illustrated in the photograph is: Open surgical biopsy Aspiration biopsy Superficial skin snip Surface skin scraping

Corynebacterium diphtheriae Cystine-tellurite or Tinsdale agar is used for the isolation of Corynebacterium diphtheriae. Corynebacteria colonies are black due to reduction of tellurite. Further differentiation may be made from observation of brown halos surrounding the black colonies, a result of cystinase activity. In addition to Corynebacterium diphtheriae, cystinase activity is also characteristic of C. ulcerans and C. pseudotuberculosis. Isolation of Bordetella pertussis and Bordetella parapertussis may be achieved with selective enrichment medium such as Bordet-Gengou or Regan-Lowe. Isolation of Legionella pneumophila may be achieved using buffered charcoal yeast extract (BCYE) with L-cysteine. Question Difficulty: Level 7

The black colonies growing on the surface of this cystine-tellurite agar plate, with dark brown halos surrounding the colonies, is one of the characteristics of: Bordetella pertussis Bordetella parapertussis Legionella pneumophila Corynebacterium diphtheriae

Absidia species Absidia species is the correct response. Of interest is the recent taxonomic reclassification of Absidia species into the genus Lichtheimia. However, the more familiar genus name Absidia is still used in laboratory practice to prevent confusion in the medical community. Although rhizoids are not observed in this photomicrograph, they are produced by Absidia. The conidiophores originate from the main hyphae between the rhizoids ("intermodal"). The conidiophores terminate in a saclike sporangium, that in early development has a distinctive funnel-like expansion, an apophysis, as seen in the image insert. Rhizopus species produce root-like rhizoids in a"nodal" placement directly below the base of the sporangiophore. At the tip of the sporangiophore is produced a saclike sporangium. Mucor species microscopic mounts also reveal a spherical, smooth-walled sporangium at the end of a conidiophore with a bulbous end rather than a funnel like expansion. Sporangiospores are contained within the sporangium and develop a yellow-brown pigmentation that is observed within the mycelium of the colony. Rhizoids are not produced. Syncephalastrum species produce spherical sporangia at the tips of narrow sporangiphores. Distinctive is the cylindrical arrangement of elongated merosporangia from the surface of the sporangium simulating "daisy petal". Tiny sporangiospores are aligned one after another in tandem within each merosporangium. Rhizoids are not produced. Question Difficulty: Level 9

The border to border extension of the mycelium as illustrated in the top photograph is characteristic of one of the Zygomycetes. Although a light yellow green pigmentation of the mycelium is observed, the identification of the isolate depends on the presentation of the fruiting body observed in the bottom photomicrograph. From these observations, select the name of this isolate from the list of multiple choices. Rhizopus species Syncephalastrum species Mucor species Absidia species

Squamous epithelial cell Large flat irregular squamous epithelial cells with a low nuclear to cytoplasmic ratio are generally found in the urine of females as a result of vaginal contamination. They are often in groups or clumps of cells. Transitional epithelial cells are smaller than the squamous epithelial cells and appear in several shapes including spherical, polyhedral, and caudate. They line the renal pelvis, calyces, ureters, and bladder and usually appear in the urine after invasive procedures such as catheterization. Renal tubular epithelial cells (RTEs) can vary in size and shape depending on their source. RTEs from the proximal convoluted tube tend to be larger, have a rectangular shape, and are called columnar or convoluted cells. Those from the distal convoluted tube are smaller and have a round or oval shape. Collecting duct RTEs have a cuboidal shape and unlike the other RTE types they appear in large sheets of cells. Macrophages would be smaller than epithelial cells and may appear vacuolated. Question Difficulty: Level 2

The cell indicated by the arrow is a: Transitional epithelial cell Renal tubular epithelial cell Squamous epithelial cell Macrophage

Left shift The cells in the photo are (A) myelocyte, (B) metamyelocyte, (C) band neutrophil, and (D) segmented neutrophil. The intended response here is left shift. A left shift is an increase in immature granulocytes, primarily band neutrophils and metamyelocytes. Other findings associated with a left shift are toxic granulation and Döhle inclusion bodies in the neutrophils. Leukemoid reaction is reserved for cell counts greater than 25.0 X 109/L (some references state greater than 50 x 109/L). This patient's WBC was 21.5 x 109/L. Leukemoid reactions are due to severe infections or inflammatory responses. Although a myelocyte and metamyelocyte are included in the composite images, the cells do not have dysplastic features suggestive of chronic myeloid leukemia (CML). The WBC counts in CML are typically much higher (>50 x 109/L). Further information would be necessary to confirm a diagnosis of CML. In leukoerythroblastosis nucleated RBC's, teardrop RBC's and immature neutrophils would be expected. The term leukoerythroblastosis refers to the presence of immature RBC's and WBC's present in the peripheral blood. Question Difficulty: Level 6

The cells included in the composite image were found in the peripheral blood smear of a patient with the following results: total WBC of 21.5 x 109/L. Differential count: metamyelocytes 4 band neutrophils 16 segmented neutrophils 48 monocytes 6 eosinophils 1 basophils 1 lymphocytes 24 This hematologic picture is most consistent with: Leukemoid reaction Chronic myeloid leukemia Left shift Leukoerythroblastosis

Transitional epithelial cells The cells depicted in this image are transitional epithelial cells. These cells originate from the renal pelvis, ureters, bladder and/or urethra and they are usually round or polygonal. They are smaller and smoother in outline than squamous cells, but larger than a white blood cell (WBC). Renal tubular epithelial cells (RTEs) can vary in size and shape depending on their source. RTEs from the proximal convoluted tube tend to be larger, have a rectangular shape, and are called columnar or convoluted cells. Those from the distal convoluted tube are smaller and have a round or oval shape. Collecting duct RTEs have a cuboidal shape and unlike the other RTE types they appear in large sheets of cells. Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. Squamous epithelial cells are the largest cells found in the urine sediment and can even be seen under low-power field. They may appear as clumps of cells and have a very large irregular-shaped cytoplasm with a prominent centrally located nucleus. Question Difficulty: Level 3

The cells shown in the image to the right are: Transitional epithelial cells Renal tubular epithelial cells Yeast cells Squamous epithelial cells

Streptomyces species The correct answer is Streptomyces species. Streptomyces species exhibit colonies that are gray white and relatively smooth. On maturity they may appear granular, powdery or floccose and acquire a light yellow brown pigment. Long, slender branching gram positive bacilli are observed in gram stained preparations. Decarboxylation reactions for casein, tyrosine, and xanthine are positive. Streptomyces species are soil bacteria of importance in the pharmaceutical industry, but can cause upper respiratory and skin infections in humans after contact while gardening or farming. Nocardia asteroides colonies are velvety to chalky and may become wrinkled on maturation, as well as develop brown yellow pigmentation. Gram stain preparations reveal gram-positive bacilli that are thin, branched and filamentous. Decomposition reactions for casein, tyrosine, and xanthine are negative, but urease is positive. N. asteroides is of low virulence and most commonly is the cause of infections in immunocompromised hosts or in those receiving antibiotics, most commonly pulmonary or wound infections at sites of intravenous infusion or shunts. Nocardia brasiliensis colonies are smooth and entire, but develop a distinctive yellow-orange pigmentation. Gram stain preparations reveal relatively broad gram positive bacilli often arranged in chains. Casein and tyrosine reactions are positive on decarboxylase agar; xanthine is negative. Recovery from subcutaneous lesions of the foot of South American field laborers is the most common clinical correlation. Oerskovia tabata colonies are small, smooth and gray yellow on maturity. Short, plump gram-positive bacilli are observed in gram stains without branching or formation of filaments. Casein hydrolysis is positive; tyrosine and xanthine are negative. Nosocomial infections are incurred in upon contact with contaminated fluids resulting in bacteremia associated with catheters and peritoneal dialysis, prosthetic joints; and, in rare cases, bacterial endocarditis. Question Difficulty: Level 9

The colonies growing on Middlebrook agar as shown in the upper left photograph were recovered after 5 days incubation from an aspirate from a superficial skin infection. The gram stain revealed branching bacilli as seen in the lower image. These organisms are acid-fast negative. Illustrated in the upper right photograph are colonies growing on casein medium demonstrating hydrolysis. The MOST likely identification is: Nocardia asteroides Nocardia brasiliensis Streptomyces species Oerskovia turbata

Oerskovia xanthineolytica Oerskovia xanthineolytica colonies on blood agar are entire, convex, smooth, yellow pigmented, and non-hemolytic. Observation of gram stains reveal coccoid to short rod-shaped gram-positive bacilli lying singly or in loose clusters. Distinctive is the production of lecithinase observed as areas of clearing around colonies growing on egg yolk agar as illustrated in the lower image. Cellumonas hominis is similar in colony and gram stain appearance to Oerskovia species. Colonies are also smooth, circular, convex, and white during initial growth, but may become yellow pigmented with maturity. Gram stains also reveal short gram-positive bacilli that are more slender than rod-shaped. The lecithinase reaction would be negative. Lactobacillus species colonies on sheep blood agar are gray-white, convex, smooth and non-discriminatory. Observation of light alpha hemolysis would help to make a presumptive identification. Microscopic observation of Gram stains reveal long, slender, gram-positive bacilli arranged in long chains rather than short bacilli in loose clusters. The lecithinase reaction would be negative. Rothia dentrocariosa colonies are pink-gray and often appear heaped and cerebriform, characteristically in a "spoke wheel" pattern, particularly in areas of confluent growth. Gram positive bacilli or cocco-bacilli are observed in diphtheroidal arrangements. The lecithinase reaction would be negative. Question Difficulty: Level 1

The colonies growing on blood agar, illustrated in the top image, are small, convex, entire, smooth, and light-yellow pigmented. Gram stain revealed short gram-positive bacilli arranged in loose clusters. Key to the identification is the positive lecithinase activity on egg yolk agar (lower image). Catalase and oxidase reactions were found to be positive and acid was produced from most carbohydrates. This is a soil organism occasionally causing nosocomial infections related to exposure to contaminated water. From these observations, select the presumptive identification of this isolate. Cellumonas hominis Lactobacillus species Oerskovia xanthineolytica Rothia dentocariosa

Porphyromonas asaccharolytica Porphyromonas asaccharolytica, as the species name indicates, is the correct response. P. asaccharolytica is among the asaccharolytic gram-negative rods. The small, entire, smooth light gray-yellow non-hemolytic colonies are non-discriminatory. Gram stains reveal small gram-negative coccoid rods arranged singly and in loose clusters. The lack of carbohydrate fermentation provided for a presumptive identification of P. asaccharolyhtica. Positive spot indole and lipase reactions are supportive. Additional biochemical assays may be required for a definitive confirmation when clinically indicated. A large proportion of strains are recovered from the oral cavity and are associated with gingivitis and root canal infections. Recovery from bite wound infections of cats and dogs have been reported. Fusobacterium nucleatum colonies on anaerobic BA are small, gray-white and convex with irregular borders and internal flecking. Beta hemolysis is not observed. On Gram stain, cells are gram negative and distinctive for being long and slender, with tapered ends. F. nucleatum is also asaccharolytic and indole positive, but lipase negative. F. nucleatum is often recovered from induced sputum specimens from hospitalized patients who develop upper respiratory infections. Bacteroides fragilis colonies on anaerobic blood agar are 1-4 mm in diameter, gray, convex, entire, semi-opaque, and non-hemolytic. Older colonies may show internal ring-like whorls. Gram-negative cocco-bacilli with rounded ends are observed in Gram stains. Indole is positive; the lipase reaction is negative. Glucose and select other carbohydrates including sucrose are fermented. B. fragilis, endogenous in the gastrointestinal tract, is a common isolate recovered from a variety of infections. Propionibacterium acnes colonies are small, enamel white, and entire without spreading. Beta-hemolysis is not observed. Gram stains reveal short gram-positive bacilli or coccobacilli singly, in V-forms, and in short chains. The indole reaction is positive (other Propionioacterium species are indole -); lipase is negative. P. acnes is part of the normal flora of the skin, nasopharynx, and oral cavity. Recovery in blood cultures is considered to be a contaminant. Question Difficulty: Level 9

The colonies illustrated in the composite blood agar/MacConkey agar to the left were recovered from an inflammatory infection of the oral cavity of a 16-year-old student. The colonies on both agar plates incubated anaerobically are small, entire, and smooth with a light gray-yellow pigmentation. Small gram-negative rods arranged singly and in loose clusters had been observed microscopically in a gram-stained preparation. Spot indole and lipase reactions are positive. Note in the image to the right the alk/alk non-fermentative carbohydrate reaction on Kligler Iron agar, with lack of fermentation of the sugars presented in the tubes to the right (asaccharolytic). Select from the multiple choices the name of this anaerobic, asaccharolytic, gram-negative isolate. Porphyromonas asaccharolytica Fusobacterium nucleatum Bacteroides fragilis Propionibacterium acnes

Pasteurella multocida Pasteurella multocida is the correct response. Colonies on blood agar are smooth, convex, spreading, gray white and non-hemolytic with a musty odor. Growth is not observed on MacConkey agar. With these colony observations and knowing that a specimen had been obtained from a cat bite infection, observing a strong spot indole reaction would provide for a presumptive identification of Pasteurella species. Positive biochemical reactions include oxidase, catalase, Voges Proskauer, and strong esculin. The decarboxylation of ornithine and arginine would provide for a definitive identification. Coccoid to rod-shaped Gram-negative bacilli are observed in Gram stains. P. multocida is endogenous in the respiratory tract of cats and other domestic and wild animals. Most human infections involve wounds and cellulitis associated with cat bites and scratches. Capnocytophaga canimorsus colonies are slow-growing, often requiring 4 - 7 days of incubation, with better growth on blood agar or other primary recovery media supplemented with cystine (such as IsoVitalex). Early colonies are pin-point, developing into slightly larger smooth convex, non-hemolytic colonies on supplemented blood agar. Growth on MacConkey agar is absent. Thin, fusiform Gram negative bacilli are seen in the Gram stain. In contrast to P. multocida, biochemical reactions for oxidase, catalase, indole, Voges Proskauer and Arginine decarboxylation are negative. Many infections are also associated with dog bites and scratches. Eikenella corrodens colonies on blood and chocolate agars are relatively small and smooth, but distinctive for pitting of the adjacent agar ("corrodens"). Light yellow pigment may be detected with a cotton swab. The colonies give a sharp odor of bleach. Gram stains reveal slender Gram-negative bacilli or coccobacilli with rounded ends. Identifying reactions include positive reactions for oxidase, nitrate reduction, and lysine and ornithine decarboxylases. Catalase, esculin, and carbohydrate utilization of most carbohydrates are negative (asaccharolytic). Cardiobacterium hominis colonies are slow-growing, small, smooth and entire on all blood culture media. Gram stains reveal Gram variable staining short bacilli that often line up in rosette-like clusters. Oxidase is positive and catalase, nitrate, urease, and esculin reactions are negative. Indole is weakly positive with spot tests often being negative. C. hominis is normal flora in the upper respiratory tract but has been recovered from blood cultures in cases of endocarditis of individuals with damaged heart valves from rheumatoid arthritis or following heart valve replacement. Question Difficulty: Level 1

The colonies illustrated in the upper photograph, recovered from a cat bite skin lesion of a child, reveal good growth of entire, convex, gray-white, smooth colonies on blood and chocolate agars. The colonies on blood agar are non-hemolytic and growth was not observed on MacConkey agar. Coccoid to rod-shaped Gram-negative bacilli are observed in the Gram stain. Positive tube reactions for indole, Voges Proskauer, ornithine, arginine, and strong production of esculin are observed in the lower photograph. The cytochrome oxidase reaction is also positive. With these observations, select the best choice for the identification of this isolate. Capnocytophaga canimorsus Pasteurella multocida Cardiobacterium hominis Eikenella corrodens

Bacillus circulans This isolate was identified as Bacillus circulans, which is consistent with the colony and Gram stain morphologies. The clue to the identification of the colony seen in the upper frame is the Gram stain in the lower frame, in which are seen short, rounded, gram positive bacilli, many of which possess distinct spores. Since the colonies grew aerobically, the presence of spores indicates Bacillus species. The colonies are spreading, smooth, yellow-white and non-hemolytic. The lack of hemolysis and the small size of the bacterial cells suggests a species other than Bacillus cereus, the species causing most human infections. Although B. circulans is most often considered a contaminant when isolated from clinical specimens, the patient's overall health status and history must be taken into consideration to determine if it is a cause of disease. Clostridium septicum also produces spores; however, this species is an anaerobe and would grow poorly, if at all, and not produce spores aerobically. Listeria monocytogenes and Lactobacillus species are gram positive bacilli; however, neither of these produce spores. Question Difficulty: Level 6

The colonies seen in the upper frame, grown after 48 hours of incubation aerobically at 35°C, and the accompanying Gram stain in the lower frame are of an organism uncommonly associated with human disease; however, this organism has been associated with septicemia, bronchopneumonia, osteomyelitis and other infections, particularly in intravenous drug users. What is the most likely identification of the organism? Clostridium septicum Bacillus circulans Listeria monocytogenes Lactobacillus species

Histoplasma capsulatum The colonies seen growing on the blood agar are gray-white and have a delicate cob-web appearance. This appearance plus the delayed growth is characteristic of one of the dimorphic fungi. The lactophenol blue mount reveals delicate background hyphae (thus the cob-web appearance of the colonies) and the production of macroconidia with a conspicuous prickly surface, characteristic of Histoplasma capsulatum. The mold form of Coccidioides immitis produces alternately staining arthroconidia and both Blastomyces dermatitidis and Paracoccidioides brasiliensis produce single, smooth microconidia, each borne on a single, thin conidiophore ("lollipops"). Question Difficulty: Level 5

The colonies shown in the upper image were obtained on blood agar from a sputum specimen after 10 days incubation at 30°C. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The delicate cob-web appearance of the colonies on blood agar (upper image) and the production of macroconidia with a conspicuous prickly surface as seen in the lower image are characteristic of: Histoplasma capsulatum Coccidioides immitis Blastomyces dermatitidis Paracoccidiodes brasiliensis

Sporotrichosis The colonies seen growing in the upper image has a gray-green, delicate, cottony consistency. The lactophenol blue mount reveals tiny, ovoid microconidia, arranged in a daisy-head pattern at the tip of a straight conidiophore. This appearance is characteristic of the mold form of Sporothrix schenckii. By moving the focus up and down in a microscopic preparation, delicate hair-like attachments may be observed for each conidium. The mold form of Coccidioides immitis produces delicate hyphae that break up into arthroconidia separated by empty cells, giving an alternatively staining appearance. The mold form of Blastomyces dermatitidis is characterized by the production of single, smooth microconidia, each borne on a single, thin conidiophore ("lollipops"). The mold form of Histoplasma capsulatum is recognized by the production of large, echinulate macroconidia, appearing as a prickly surface. Question Difficulty: Level 5

The colonies shown in the upper image, obtained from a biopsy of an ulcerating skin lesion of the arm, are growing on agar slants of Sabouraud's dextrose agar. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony growing in the left slant. The diagnosis is: Coccidioidomycosis Blastomycosis Histoplasmosis Sporotrichosis

Morganella morganii The colonies shown on the 5% blood agar plate are relatively large, dirty gray and are not swarming. The colonies growing on MacConkey agar show no red pigmentation; therefore, the bacterial species is a non-lactose fermenter. Of the responses given, only Proteus and Morganella are non-lactose fermenters and would give the appearance of colorless colonies on MacConkey agar. Morganella morganii, which does not swarm on blood agar, is the correct choice. Escherichia coli is a lactose fermenter and would produce red colonies on MacConkey agar. Enterobacter sakasakii is a lactose fermenter and would produce red colonies on MacConkey agar. In addition, E. sakasakii would produce yellow pigmented colonies on 5% sheep blood agar, not seen in this photograph. Proteus mirabilis would produce colonies similar in appearance to those seen here on MacConkey agar but would swarm on 5% sheep blood agar with a spreading, film covering the surface. Therefore, by exclusion, the non-lactose fermenter, Morganella morganii, which also does not swarm on blood agar, is the correct choice. Question Difficulty: Level 7

The colonies shown in this 5% sheep blood agar (left) and MacConkey agar (right) split frame photograph are most likely those of: Escherichia coli Enterobacter sakasakii Proteus mirabilis Morganella morganii

Cryptococcus neoformans The colonies seen growing on the bird seed agar appear smooth and have a distinct reddish-brown pigmentation. The active ingredient in bird seed (Guizotia abyssinica) agar is caffeic acid, which is extracted and placed in an agar containing 1% glucose. Of the cryptococci, and other species of yeasts, Cryptococcus neoformans selectively produces the enzyme phenoloxidase, which oxidizes the caffeic acid in the medium to melanin, producing the red-brown pigmentation. The other yeast species included in this exercise remain cream colored (non-pigmented), when grown on bird seed agar as they do not possess phenoloxidase activity. Question Difficulty: Level 3

The colonies shown in this photograph were grown on Guizotia abyssinica (bird seed) agar at 30°C for 72 hours. The most likely identification is: Cryptococcus laurentii Cryptococcus neoformans Candida parapsilosis Saccharomyces cerevisiae

Trichoderma Trichoderma is the intended selection. The border to border extensions of the colony is similar to those of Gliocladium except the surface pigmentation is light yellow green rather than deep green. Microscopically observed are small rather than large dense clusters of spherical conidia, here located at the tips of short conidiophores that are projected laterally from the hyphae. Acremonium colonies are gray to light shades of yellow with a smooth surface. Conidia are arranged in loose clusters, each borne at the tip of a long, slender conidiophore ending in a blunt tip. A septum is observed at the base of each conidiophore. Fusarium colonies are cottony or wooly with a distinctive lavender, pink, deep red or magenta coloration. Microscopic Identification is usually made by observing macro-conidia that are long, sickle-shaped, and multi-celled, with transverse septa separating the cells from one another. Exact focusing on the hilar cell reveals a hair-like "foot cell" extension. Gliocladium colonies also have a border to border "lawn-like" extension along the Petri dish but with a green pigmentation. Illustrated in the photomicrograph are large clusters of densely packed spherical conidia borne from the tips of fingerlike conidiophores, simulating a penicillus in structure. Question Difficulty: Level 5

The colony illustrated in the top image developed after 4 days of growth on Sabouraud's dextrose agar. Note the extension of the outer margin to the rim of the Petri dish. The bottom image 2 is a methylene-blue stained image of an inoculum obtained from the surface of the colony. From these characteristics, select the fungus genus from the multiple choices. Trichoderma Fusarium Acremonium Gliocladium

Rhizopus species Rhizopus species is the correct response. The rapid growth of the colony and border to border extension of the surface mycelium is characteristic of one of the Zygomycetes. Note in the lower part of the photomicrograph the root-like structure, known as a rhizoid, key to the identification of Rhizopus species. Also distinctive is the "nodal" placement of the rhizoid directly below the base of the sporangiophore at the tip of which is saclike sporangium. Lichtheimia, (formerly Absidia) species produce rhizoids, but they are located in an inter-nodal position between the origin of the conidiophores rather than directly adjacent. The conidiophores terminate in a saclike sporangium, that in early development has a distinctive funnel like expansion (apophysis). Mucor species do not produce rhizoids. Microscopic mounts reveal a spherical, smooth-walled sporangium at the end of a conidiophore with a bulbous end. Sporangiospores are also contained within the sporangium and develop a yellow-brown pigmentation in maturity that is observed as pigment within the mycelium of the colony. Syncephalastrum species also produce spherical sporangia at the tips of narrow sporangiphores. Distinctive is the cylindrical arrangement of elongated merosporangia from the surface of the sporangium simulating a "daisy petal" rather than being produced internally. Tiny sporangiospores are aligned one after another in tandem within each merosporangium. Rhizoids are not produced. Question Difficulty: Level 1

The colony shown in the upper image was recovered from the nasal exudate of a 28-year-old construction worker with sinusitis. The colony grew in 3 days on SabHI agar (combination of Sabouraud dextrose and BHI agar) incubated at 30o C. Note the border-to-border extension of the surface mycelium. As the colony is not species-specific, the identification of this isolate can be made by observing the lower, lactophenol blue-stained image. From these observations, select the identification of this isolate. Mucor species Rhizopus species Lichtheimia species (formerly Absidia) Syncephalastrum species

Iron deficiency Iron deficiency would be the correct answer in this case, since this condition is associated with microcytosis and hypochromia. Hemolytic anemia, myelodysplasia, and liver disease may each fit this peripheral blood picture. Each of these conditions can display peripheral blood macrocytosis. It is easy to observe the overall larger size of the red blood cells in this image compared to the normal lymphocyte also present. When macrocytes are present, they should be examined for their shape (round vs. oval), the hemoglobin content (central pallor), and whether or not there are any inclusions present in the cell. Question Difficulty: Level 9

The complete blood count was obtained from a patient recently admitted to the emergency room. The red blood cell indices obtained revealed an MCV of 115 femtoliters (fL) (normal range 80 - 90 fL). The patient met the criteria for a peripheral blood smear examination. A representative field is shown on the right. All of the following conditions would be indicated by the results seen on this peripheral blood smear EXCEPT? Hemolytic anemia Myelodysplasia Iron deficiency Liver disease

Iron deficiency anemia The red blood cells are microcytic and hypochromic and can be seen in iron deficiency. Microcytes have pale or hollow centers. In contrast, spherocytes are solidly stained. Therefore, both congenital spherocytosis and hemolytic anemia with its spherocytic component are ruled out. Some observers may interpret as artifact the hollow nature of the red cells with such distinct borders between emptiness and the boundary of hemoglobin containment. Additional studies and complete medical history and/or repeat smears may be indicated for clarification. Note the absence of polychromasia in any red cells. This is further evidence of iron deficiency. Question Difficulty: Level 3

The condition most likely associated with the peripheral blood picture shown in the photograph is: Congenital spherocytosis Autoimmune hemolytic anemia Iron deficiency anemia Artifact of staining

Yeast This slide shows yeast cells.Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. Red blood cells (RBCs) are slightly smaller than WBCs and have a smooth, non-nucleated appearance. Renal tubular epithelial cells (RTEs) can vary in size and shape depending on their source. RTEs from the proximal convoluted tube tend to be larger, have a rectangular shape, and are called columnar or convoluted cells. Those from the distal convoluted tube are smaller and have a round or oval shape. Collecting duct RTEs have a cuboidal shape and unlike the other RTE types they appear in large sheets of cells. Leukocytes have a rough appearance and contain granules and multilobed nuclei which fill out the cytoplasm of the cell. Renal epithelial cells and leukocytes have nuclei. These cells do not have nuclei. Leukocytes are also present in this field, but the arrows point only at yeast cells. Question Difficulty: Level 1

The constituents that are indicated by the arrows in this image of a stained urine sediment are: Red blood cells Yeast Renal epithelial cells Leukocytes

Cystine crystal A cystine crystal is depicted in this image. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. These are bilirubin crystals. Bilirubin crystals are gold-orange, needle-like crystals that may appear in clumps, as indicated by the left arrow in this image. They are found in acid urine and are associated with liver disease. Leucine crystals are associated with liver disease and are found in acid to neutral pH urine specimens. One will notice the yellow color, concentric circles, and the radial striations as characteristics of leucine crystals. Question Difficulty: Level 1

The crystal is seen in this image is a: Leucine crystal Bilirubin crystal Cystine crystal Cholesterol crystal

Leucine crystals These are leucine crystals and are associated with liver disease. They are found in acid to neutral pH urine specimens and are yellow in color. Notice the concentric circles and the radial striations. Bilirubin crystals are gold-orange, needle-like crystals that may appear in clumps. They are found in acid urine and are associated with liver disease. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Question Difficulty: Level 1

The crystals seen in this image are: Bilirubin crystals Leucine crystals Cystine crystals Cholesterol crystals

Curvularia species The correct answer is Curvularia species. The macroconidia of Curvularia species have cells separated by true septa extending from the cell wall. The multi-celled, dark brown, macroconidia are bow- or boomerang-shaped due to overgrowth of the central cells. Stemphylium species microscopically are characterized by the production of dark brown, oblong or broadly elliptical, multi-celled, muriform conidia that are supported by a straight conidiophore (so-called "bale of cotton on a stick"). Bipolaris species produce smooth-walled, oblong-shaped, multi-celled conidia with the individual cells surrounded and separated by a sac-like wall called a distosepta that is not part of the cell wall. The macroconidia are borne sympodially from bent, geniculate conidiophores. Question Difficulty: Level 4

The curved, multi-celled, dark brown staining macroconidia divided by transverse septa that can be observed in the photomicrograph on the right is characteristic of which of the following species of dematiaceous fungi? Bipolaris species Stemphylium species Curvularia species

Inadequate stool fixation Inadequate stool preservation is the intended response. If the parasitic forms within a specimen have not been adequately fixed, the trichrome stain will be poorly adsorbed. Although the cyst illustrated in the photograph has features suggestive of Entamoeba histolytica, the stain does not allow an adequate interpretation of the nuclear karyosome or the exact nature of the chromatin rings. It is difficult to count the number of nuclei making a definitive identification difficult. This form was later identified as Entamoeba coli, possibly avoiding a misdiagnosis and over-treatment. Weak staining solution is an incorrect response. Use of weak solutions might be the source of this poor stain; however, note that the stain is dark and even in texture. A weak solution appears not to be the problem with the overall intensity of staining, but may still have a lack of detail. Insufficient time of staining does not seem to be an issue as the cyst shows even, dark staining. If the time had not been adequate, the intensity of color would be compromised and would be uneven or diminished. Selection of wrong stain possibly should be considered; however, if the specimen had not been properly preserved, other stains may have resulted in an equally poor quality result. Question Difficulty: Level 9

The cyst as illustrated in the photograph was observed in a permanently stained smear of a stool specimen. Making a presumptive identification would be difficult because of the poor quality of the stain and the lack of internal detail. From the multiple-choice answers listed below, select the most likely cause for the poor staining quality observed in this cyst. Weak staining solution Inadequate stool fixation Insufficient time of staining Selection of wrong stain

A delay in growth beyond five days A delay in growth beyond five days is the correct response. Characteristically, the growth of colonies for the dematiaecous fungi serving as agents of chromomycosis is longer than the agents of phaeohyphomycosis, usually extending beyond five days. In most instances, the final genus/species identification requires study of a microscopic mount. Colonies with a velvety appearance of the surface mycelium, with a dark brown to black colony reverse side and having a distinct outer border with dark staining of the colony, included with the remaining features as listed responses to this exercise, do not distinguish between agents of chromomycosis and phaeohyphomycosis. Question Difficulty: Level 1

The dark brown, wooly to velvety surface of the colony shown in this image suggests one of the dematiaceous fungi. What additional feature would suggest recovery of one of the agents of chromomycosis, rather than one of the phaeohyphomycetes? The velvety appearance of the surface mycelium A delay in growth beyond five days Dark brown to black staining of the reverse side of the colony Distinct outer border with dark staining of the colony margin

Red blood cell cast This is a red blood cell cast. Red blood cells (RBCs) can be identified within the matrix of the cast. The identification of the cast as a red blood cell cast is supported by the appearance of RBCs outside of the cast. Granular casts are composed of plasma protein aggregates and cellular remnants. They usually indicate renal parenchymal disease, or allograft rejection. Granular casts appear as cylinders of coarse, or fine, highly refractive particles. Hyaline casts generally appear as colorless, homogeneous, and transparent with rounded ends. They can also be seen as a result of dehydration, after diuretic therapy, in renal disease, and transiently as a result of exercise. There are approximately 5 hyaline casts in this image. Renal tubular epithelial (RTE) casts are caused by the sloughing of necrotic renal tubular cells due to advanced tubular destruction. They can be due to allograft rejection, acute tubular necrosis, and certain drugs. RTE cells are usually seen as part of the cast. Question Difficulty: Level 2

The element that is indicated by the arrow is a: Red blood cell cast Granular cast Hyaline cast Renal tubular epithelial cast

Mycobacterium gordonae Mycobacterium gordonae is the correct response. The yellow pigmented colonies when observed prior to exposure to light indicate the presumptive identification of one of the scoto-chromogens, of which M. gordonae is included. The positive Tween 80 reaction supports this identification. Catalase is also positive; most other biochemical reactions used for the identification of Mycobacterium species are negative. M. gordonae rarely causes human infections, although rare cases of meningitis secondary to ventricular shunts and peritonitis in patients undergoing peritoneal dialysis have been reported. Mycobacterium fortuitum is a non-chromogen and produces smooth, waxy, gray-white colonies that remain non-pigmented even after exposure to light. Also characteristic is "rapid growth" within 5 - 7 days. M. fortuitum is chemically active producing positive reactions for Tween 80 and most other biochemicals used for testing the Mycobacteria, with the exception that the niacin test is negative. M. fortuitum is a common cause of nosocomial infections, particularly of the skin at sites of trauma or scratches after contact with contaminated water. Keratitis in wearers of soft and hard contact lenses has also been reported. Mycobacterium kansasii is a photo-chromogen and would produce colonies with yellow pigmentation only after exposure to light. Mature colonies are more rough than smooth. Tween 80 reactions are also positive, but in contrast to M. gordonae, most other biochemical reactions are also positive although catalase is negative. Chronic pulmonary infection resembling classic tuberculosis is a common clinical manifestation. Mycobacterium marinum is also a photo-chromogen and would produce colonies with yellow pigmentation after exposure to light. The Tween 80 and catalase reactions are also positive, including many additional biochemical reactions beyond those few positive reaction observes for M. gordonae. Most infections with M. marinum involve the skin, particularly when open wounds or skin abrasions come in contact with a contaminated water source. Question Difficulty: Level 9

The entire, smooth, convex Mycobacterium species colonies growing on 7H10 agar were observed to be dark yellow pigmented early in culture even before having been exposed to light. This isolate was found to be Tween-80 positive as seen in the reaction tubes in the bottom photograph. Select from the multiple choices the presumptive identification of this isolate: Mycobacterium gordonae Mycobacterium fortuitum Mycobacterium kansasii Mycobacterium marinum

After irradiating a unit of packed red blood cells, how is the expiration date affected? The expiration date is changed to 28 days from the date of irradiation regardless of the original expiration date. The expiration date shortens to 28 days from the date of irradiation or the original expiration date, whichever is first. The expiration date is shortened to 24 hours from time of irradiation. The expiration date is not affected.

The expiration date shortens to 28 days from the date of irradiation or the original expiration date, whichever is first. The expiration date of irradiated packed red blood cells is changed to 28 days from the date of irradiation. However, if the original expiration date is sooner, the unit retains the original expiration date. Irradiation causes damage to the red cell membrane. Subsequently, the plasma potassium level in irradiated units is higher, and ATP and 2,3-DPG levels are lower. These effects necessitate a shorter expiration date for the safety of a potential recipient. Question Difficulty: Level 9

Multiple Myeloma The correct answer is: Multiple Myeloma The diagram on the right demonstrates a narrow spike in the gamma region (also known as an "M-spike"). This suggests a monoclonal gammopathy. In this case, a single type of monoclonal antibody is being produced in large amounts by numerous plasma cell clones, all originating from a single malignant plasma cell. This is indicative of multiple myeloma. While the other choices are not correct, it's important to know how the curves would look in those disease states. Malnutrition or nephrotic syndrome would result in depressed levels of albumin and all proteins. In acute inflammation, alpha 1 antitrypsin would be elevated, increasing the height of the alpha 1 band. Question Difficulty: Level 5

The following diagram demonstrates two Serum Protein Electrophoresis (SPEP) patterns from different patients. The pattern on the left appears to be from a normal, healthy patient. The pattern on the right is from a patient with a particular disorder. What disorder is suggested by the pattern on the right? Nephrotic Syndrome Acute inflammation Malnutrition Multiple Myeloma

X-linked agammaglobulinemia The correct answer is: X-linked agammaglobulinemia The diagram on the right indicates a slump in the entire gamma region. This suggests an immunodeficiency such as X-linked agammaglobulinemia (Bruton type) which is particularly brutal in that these individuals do not generate mature B cells and completely lack antibodies in their bloodstream. Alpha 1 antitrypsin deficiency would be visible as a depressed alpha 1 band. On the other hand, acute inflammation would increase the levels of alpha 1 antitrypsin, increasing the height of the alpha 1 band. Nephrotic syndrome would be manifested by a decrease of all proteins, especially albumin. Question Difficulty: Level 9

The following diagram demonstrates two Serum Protein Electrophoresis (SPEP) patterns from different patients. The pattern on the left is from a normal, healthy patient. The pattern on the right is from a patient with a particular disorder. What abnormality is suggested by the pattern on the right? Alpha-1-antitrypsin deficiency X-linked agammaglobulinemia Nephrotic syndrome Acute inflammation

Beta Hemolysis The blood agar plate in the illustration is showing beta-hemolytic bacterial growth. Beta hemolysis is the clear zone that surrounds the bacterial colonies in which the red blood cells have been lysed. This phenomenon is associated with some forms of Streptococcus that produce streptolysin; an enzyme produced by the bacteria which causes the complete lysis of red blood cells. Alpha hemolysis is the partial lysis of red blood cells in blood agar that results in a greenish discoloration around the colony. Streptococcus pneumoniae and the viridans streptococci are examples of two organisms that produce alpha hemolysis. No change to the agar surrounding a colony on blood agar is referred to as gamma hemolysis. The coagulase-negative staphylococci are an example of gamma hemolytic organisms. Haemophilus species require X and V factors for growth. Haemophilus species will form tiny colonies when grow in close proximity to organisms that produce NAD (or V factor) such as Staphylococcus aureus. This phenomenon is referred to as satellitism. Question Difficulty: Level 2

The following is the term used to describe the total clearing of the agar surrounding colonies on a blood agar plate as seen in this illustration: Alpha Hemolysis Beta Hemolysis Gamma hemolysis Satellite formation

Microcytic, hypochromic When compared to the nucleus of the lymphocyte in the field, the cells are smaller. These cells are categorized as microcytic. The amount of central pallor is greater than cells with a normal amount of hemoglobin. The chromicity of the cells is less than normal and are categorized as hypochromic. Normocytic, normochromic cells would be a size similar to the nucleus of the lymphocyte in the field. The chromicity of the cells would have a normal central pallor. Hypochromic cells of normal size would have a greater than normal central pallor. Macrocytic cells would be larger than the nucleus of the lymphocyte in the field. Hypochromic cells would have a larger than normal central pallor. Question Difficulty: Level 5

The following smear was forwarded to the technical supervisor for confirmation of RBC morphology. Which of the following is an appropriate set of descriptors? Normocytic, normochromic Normocytic, hypochromic Microcytic, hypochromic Macrocytic, hypochromic

B Option B is the correct answer. The colonies of M. kansasii are considered a photochromogen and develop pigment only when exposed to light. Option A shows the expected rough and buff growth seen with Mycobacterium tuberculosis. They usually take two to three weeks to reach maturity. Option C shows the colonies of M. scrofulaceum, a scotochromogen. They are smooth and develop a deep yellow pigment even when incubated in the dark. Option D shows colonies of M. fortuitum. They are white or gray-white and are rapidly growing (within 3 days of incubation). Question Difficulty: Level 8

The four mycobacteria shown have been cultured on Middlebook agar and include the duration of their incubation. Which of the organisms is most characteristic of the growth seen with Mycobacterium kansasii? A B C D

A contaminant The microscopic features shown here represent Scopulariopsis species. In most instances, particularly if a patient does not have underlying immunologic or hematologic disease, Scopulariopsis species should be considered a contaminant when recovered from a sputum specimen. However, if there is clinical or X-ray evidence of mycotic pulmonary infection, additional daily induced sputum specimens should be obtained. If Scopulariopsis species or any other hyaline mold is recovered from two or more successive specimens, its potential as a pathogenic agent should be considered. Scopulariopsis species have been reported as the agents of pulmonary fungus ball infections in patients with preexistent cavities and as a cause of pneumonia in patients with leukemia. Invasive pulmonary disease by this agent has not been reported. Question Difficulty: Level 7

The fungus illustrated in this photomicrograph was recovered from an induced sputum specimen from a 74 year old man with chronic obstructive pulmonary disease. This isolate is most likely: The cause of chronic bronchitis The cause of invasive pulmonary disease The cause of allergic bronchopulmonary disease A contaminant

Pseudomonas stutzeri Pseudomonas stutzeri is the correct response. Colonies on blood agar are spreading, convex and wrinkled with a yellow-white pigmentation. Colonies on MacConkey agar are characteristic of a non-fermenter and devoid of the green pigmentation indicating lack of pyocyanin production. A gram stain would reveal long gram negative bacilli comparable to Pseudomonas aeruginosa, along with other biochemical characteristics, including a positive oxidase reaction. Characteristic of Pseudomonas stutzeri is reduction of nitrates, hydrolysis of starch, and arginine negative. Burkholderia cepacia is incorrect because the colonies are relatively small, convex, and smooth devoid of "wrinkles", with gray yellow pigmentation. Colonies on MacConkey agar are non-pigmented characteristic of a non-fermenter and negative for pyocyanin production. The oxidase reaction is positive, nitrate denitrification is negative, lysine is positive, and is resistant to Polymyxin B. Elizabethkingia meningoseptica is incorrect because it produces circular, smooth colonies with light yellow pigment on media. It doesn't grow well on MacConkey. Acinetobacter baumannii is incorrect because colonies are white, convex, and smooth without wrinkles on blood agar. Colonies growing on MacConkey agar are smooth to finely wrinkled, with a light pink pigmentation, devoid of pyocyanin production. The oxidase reaction is negative. A Gram stain reveals gram negative coccobacilli that can falsely appear as a gram positive coccobacilli when grown in blood culture medium. Question Difficulty: Level 5

The granular, wrinkled, yellow-pigmented colonies shown in the upper photograph were recovered on chocolate agar after 48 hours of incubation from a respiratory specimen collected from a patient with cystic fibrosis. Note in the lower composite photograph that colonies on the surface of blood agar are flat, granular, and only slightly wrinkled. On MacConkey agar the colonies lack lactose fermentation and lack pyocyanin production. The spot oxidase test is positive, and nitrates are reduced. With these observations, select the presumptive identification of this isolate. Pseudomonas stutzeri Burkholderia cepacia Elizabethkingia meningoseptica Acinetobacter baumannii

Coccidioidomycosis Coccidioidomycosis is the correct answer because the colonies seen growing on the blood agar are gray-white and have a delicate hair like consistency. The dark pigmentation indicates that some of the hemoglobin may have been absorbed from the culture medium. This appearance plus the delayed growth is characteristic of one of the dimorphic fungi. The lactophenol cotton blue mount reveals thin hyphae that are breaking up into arthroconidia separated by empty cells, giving an alternately staining appearance. This is characteristic of the mold form of Coccidioides immitis. Blastomycosis is incorrect because the mold form of Blastomyces dermatitidis is characterized by the production of single, smooth microconidia, each borne on a single, thin conidiophore ("lollipops"). Histoplasmosis is incorrect because the mold form of Histoplasma capsulatum is recognized by the production of large, echinulate macroconidia, appearing as a prickly surface. Paracoccidioidomycosis is incorrect because the mold form of Paracoccidioides brasiliensis produces conidia similar to Blastomyces dermatitidis; in addition, to multiple budding cells attached to a parent cell resembling a mariner's wheel. Question Difficulty: Level 6

The growth of the colonies shown in the upper image was obtained on blood agar from a sputum specimen after 8 days of incubation at 30°C. The lower image is a photomicrograph of a lactophenol cotton blue mount made from a portion of the colony. The diagnosis is: Coccidioidomycosis Blastomycosis Histoplasmosis Paracoccidioidomycosis

Candida parapsilosis Candida parapsilosis is the correct response. Characteristic is the delicate satellite growth observed microscopically along the streak lines of a subculture. Note the microscopic view the radial arrangement of delicate conidiophores producing tiny conidia, colloquially referred to as a "sagebrush" pattern. As C. parapsilosis has been found as normal flora of cutaneous and mucocutaneous surfaces, recovery in laboratory cultures is usually considered to be a contaminant. Candida glabrata produce uniform, small, spherical cells arranged in relatively tight clusters rather than from narrow conidiophores in a "spider web" arrangement as seen with C. parapsilosis. The identification can be confirmed by demonstrating the assimilation of both glucose and trehalose. C. glabrata among the species of yeasts is a common isolate from urinary tract infections. Candida kefyr is characterized by the abundant production of relatively large, elongated, rectangular blastoconidia that arrange in distinct loose-like clusters simulating the appearance of "logs in a stream", rather than in the "sagebrush" pattern. Candida krusei is characterized by the production of long blastoconidia that grow in short branches from the mycelium, with the production of elongated cells in a treelike or crossed matchstick arrangement rather than as branching "sagebrush". Question Difficulty: Level 9

The growth of yellow-white yeast colonies with a smooth or hair-like surface within 2 - 3 days on non-selective culture media generally requires further procedures to make a presumptive identification. Microscopic observation of the subculture of colonies growing on cornmeal agar is one such approach, as illustrated in the photomicrograph. Note the spider-like colonies that appear along the streak line. From the multiple choices, select the name of the presumptive yeast identification. Candida glabrata Candida parapsilosis Candida kefyr Candida krusei

Delta-beta thalassemia minor Decreases in both Hb A and A2 and an increase in Hb F correlates with delta-beta thalassemia minor. Delta-Beta Thalassemia results from a deletion in both the delta and beta genes on chromosome 11, preventing the appropriate production of hemoglobins A2 and A respectively. The gamma genes on the affected chromosome increase their production of gamma globin thereby increasing the amount of HbF. Beta thalassemia minor is the result of one beta gene on chromosome 11 being defective that will show a minor decrease in beta globin due to the fact that one gene is still producing functioning beta globins. Beta thalassemia major is the result of both beta genes on chromosome 11 being defective that leads to a severe decrease in beta globin. Alpha thalassemia major is a deletion of all four alpha globin genes on chromosome 16 that leads to hydrops fetalis. Most patients with this die soon after birth or in utero. Question Difficulty: Level 7

The hemoglobin electrophoresis pattern for patient #2 shows an increase in Hb F and a decrease in both Hb A and Hb A2. These results correlate best with which of these thalassemias? Beta thalassemia minor Beta thalassemia major Delta-beta thalassemia minor Alpha thalassemia major

Cystoisospora belli Cystoisospora belli is the correct response. The oocysts of Cystoisospora belli are large, measure up to 30 µm, and have a long oval shape. The oocysts have a thin, smooth outer wall and possess two intra-cytoplasmic sporocysts (immature oocysts may possess only a single sporocyst). In immunocompetent patients, disease with C. belli is typically self-limiting, but is usually more serious in immunocompromised patient. Giardia duodenalis cysts may present with only two nuclei, although as many as 4 may be observed. Each nucleus possesses a small karyosome that is eccentrically placed, a presentation not observed here. Dientamoeba fragilis does not have a cyst stage that has been identified and produces human infections only as a trophozoite. The trophozoite contains many food vacuoles and bacteria in its cytoplasm. Chilomastix mesnili oocysts contain only a single nucleus with a small central karyosome. Within the cytoplasm is a prominent vacuolated cytostome adjacent to the nucleus with a "shepherd crook" to one side. Question Difficulty: Level 5

The high power photograph was taken from a saline wet preparation of a stool specimen. The patient, a 45-year-old male with AIDS who recently returned from a vacation to Mexico City, was suffering from recurrent diarrhea. Based on the morphology of the oocyst, select from the multiple choices the most probable presumptive identification. Giardia duodenalis Cystoisospora belli Dientamoeba fragilis Chilomastix mesnili

Iodamoeba bϋtschlii cyst The cysts of Iodamoeba bϋtschlii may be readily identified by its size (approximately 12 μm) and by the presence of a well-defined glycogen mass. Furthermore, the large karyosome and absence of peripheral chromatin that constitutes the single nucleus help to distinguish them from the other amebic cysts. This organism is non-pathogenic. Entamoeba hartmanni cyst is a smaller version of Entamoeba histolytic. It is 5-10 μm with 1-4 nuclei, a small centrally located karyosome, and possibly a round, blunt, chromatoid body. It is non-pathogenic. Entamoeba coli cysts are typically 10-35 5-10 μm, may contain 5-8 visible nuclei each with a small eccentric karyosome. If the chromatoid body is visible, it typically has splintered ends. This organism is non-pathogenic. Endolimax nana cysts measures 5-10 μm, may contain 2-4 visible nuclei each with a small eccentric or centrally located slightly larger karyosome. There is typically no visible peripheral chromatin. Question Difficulty: Level 5

The illustration demonstrates a non-pathogenic amoeba described as being 5-20 um, containing a large glycogen mass, and a single nucleus with a large karyosome and no peripheral chromatin: Entamoeba hartmanni cyst Entamoeba coli cyst Endolimax nana cyst Iodamoeba bϋtschlii cyst

Sickle cells The cells are sickle cells, which are crescent-shaped red blood cells. These abnormal red blood cells contain hemoglobin S, which causes the fragility associated with these cells. Patients with sickle cell anemia can experience vaso-occlusive crises, where blood vessels become blocked with sickle cells and oxygen delivery beyond the blockage is decreased. In addition, individuals with sickle cell anemia are typically more likely to experience a higher infection risk due to sickle cells damaging splenic tissue. It is common to see a decreased hemoglobin and hematocrit with a higher reticulocyte count in patients suffering from sickle cell anemia since sickle cells have a shortened life span and new cells must be created faster to replace them. Ovalocytes, ovalo-macrocytes, are oval or elongated red cells. These cells are associated with megaloblastic anemia (e.g., vitamin B12 or folic acid deficiency) and other causes of macrocytosis (e.g., liver disease). Schistocytes are fragments of red cells. They form when red cells are ruptured in circulation, such as in case of disseminated intravascular coagulation (DIC) where fibrin strands are deposited in the vascular lumen. Acanthocytes have irregular projections on the surface. Presence of acathocytes are associated with severe liver disease or abeta-lipoproteinemia. Question Difficulty: Level 1

The image is a representative field from the peripheral blood smear. What cells are indicated by the arrows in this smear? Sickle cells Ovalocytes Schistocytes Acanthocytes

Leukemia with CNS involvement Allergic reactions, bacterial/viral meningitis do not cause the presence of blasts to be noted in the CSF. Leukemia with CNS involvement will show immature cells, similarly to the peripheral blood smear. An allergic reaction will show predominantly eosinophils. Bacterial meningitis will show mainly neutrophils. A broad spectrum of lymphocytes and monocytes would be present in a case of viral meningitis. Question Difficulty: Level 4

The image is a stained smear of cerebrospinal fluid. The cells present in this field may indicate what condition? Allergic reaction Bacterial meningitis Leukemia with CNS involvement Viral meningitis

Macrophages The three cells are macrophages, notice the large amount of cytoplasm and the vacuoles. These are normal cells that are not malignant. Macrophages can appear in the CSF as well as arachnoid mesothelial cells (the cell on the left). There are no eosinophils or neutrophils present in this image. Question Difficulty: Level 7

The image is a stained smear of cerebrospinal fluid. What type of cells are the three right cells in this field? Eosinophils Macrophages Malignant cells Neutrophils

They line the arachnoid space. The cells seen here are ependymal cells which are found in the tissues lining the ventricles, the neural canal, and the arachnoid space. Notice the less distinct cell borders and the nucleoli. Question Difficulty: Level 5

The image is a stained smear of cerebrospinal fluid. Which of the following statements is true about the cells shown at the right? Their numbers are increased when the patient has leukemia. Their numbers are increased when the patient has multiple sclerosis. They line the arachnoid space. They are capable of engulfing red cells.

Siderotic granules The correct answer is siderotic granules. Siderotic granules are iron granules of non-heme iron, resulting from an excess of available iron in the body. The granules appear blue/green with Prussian blue stain, as noted in this image. Pappenheimer bodies are also iron granules of non-heme iron, however, Pappenheimer bodies are seen in a Wright stain. It is important to note that even though Pappenheimer bodies and siderotic granules are the same inclusion, they are designated differently depending on the stain used. Howell-Jolly bodies are nuclear remnants of DNA that resemble a dark-purple, large dot. Howell-Jolly bodies will be seen with Wright stain, not a Prussian blue stain. Heinz bodies are large, dark-purple dots that result from denatured or precipitated hemoglobin. Heinz bodies can only be seen when using a supravital stain. Question Difficulty: Level 3

The image is of a peripheral blood smear stained with Prussion blue stain. What are the inclusions seen in the RBC indicated by the arrow? Siderotic granules Pappenheimer bodies Howell-Jolly bodies Heinz bodies

Erythrocytes Platelets and erythrocytes do not have CD 45 on their cell surfaces. Virtually all cells in the gated population have CD45 surface antigens and are therefore all leukocytes (white blood cells) - which includes all cells of lymphoid and myeloid origin, except for platelets and erythrocytes. Lymphocytes, monocytes and granulocytes all have CD 45 on their surface, and thus could be among the population that tested positive. Question Difficulty: Level 3

The image on the right contains the fluorescence data from CD45 from a flow cytometry analysis. Note that virtually all cells in the gated population have CD45 surface antigens. These cells could therefore be any of the following EXCEPT: Erythrocytes Lymphocytes Monocytes Granulocytes

Histogram with a shift to the left When compared to the nucleus of the lymphocyte present in the image, the majority of the red cells are microcytes. The histogram would be normal width due to the homogenous, single cell population present; but would demonstrate a left shift. A histogram with a double peak would be seen when a peripheral smear demonstrates two specific cell populations. A widened histogram would represent a heterogeneous red cell population. A histogram with a shift to the right would indicate the presence of macrocytic (larger than normal) red blood cells. Question Difficulty: Level 8

The image on the right is a representative field from a peripheral blood smear. What characteristics would describe the red cell distribution curve that you would expect to see? Histogram with two peaks Histogram with a shift to the left Histogram that is wider than normal Histogram with a shift to the right

Aspergillus niger The colony that is represented in this image is Aspergillus niger. A mature colony has a "peppered "effect, due to the thick black conidia covering the surface. Acremonium species typically produce a smooth, pastel rose pigmented colony. The colony of Microsporum canis is usually cottony white with a lemon-yellow apron. Scopulariopsis species produce a buff-brown colony with distinctive radial rugae. Question Difficulty: Level 2

The image on the right of a mold colony on an agar plate is most representative of which of the following molds? Acremonium species Microsporum canis Scopulariopsis species Aspergillus niger

Enterococcus spp., Resistant to vancomycin D is the correct answer. Enterococcus spp. are bile esculin positive and grow in 6.5% NaCl. If they grow on the 6 µg/mL vancomycin screen agar as this isolate does, it is vancomycin resistant. If there is no growth on the 6 µg/mL vancomycin screen agar, the isolate is susceptible to vancomycin. Streptococcus Group D, not Enterococcus will not grow in the 6.5% NaCl and should not be tested for vancomycin resistance. Staphylococcus epidermidis is catalase positive. Question Difficulty: Level 4

The images below represent a gram-positive, catalase-negative, non-motile coccus inoculated to bile esculin agar, 6.5% NaCl broth and to 6 µg/mL of vancomycin in Mueller Hinton agar. It should be reported as: Enterococcus spp., Susceptible to vancomycin Streptococcus Group D, not Enterococcus Staphylococcus epidermidis, Resistant to vancomycin Enterococcus spp., Resistant to vancomycin

Mycobacerium scrofulaceum The clinical manifestation of Mycobacterium scrofulaceum is scrofula, an enlargement of posterior cervical lymph nodes, as seen in the lower right image. This infection occurs most commonly in young children at the time they are cutting teeth, with commensal organisms in the posterior oropharynx accessing the lymphatic channels with extension to the regional lymph nodes. Mycobacterium tuberculosis causes pulmonary tuberculosis and usually involves the upper lobes, as shown in the lower left image. M. tuberculosis would be the most likely to produce the bilateral upper lobe infiltrates as shown. Mycobacterium marinum grows optimally at 30-32° C and most commonly causes subcutaneous skin infections, as seen in the upper right image. Usually infections are due to exposure or injury in freshwater or saltwater. Mycobacterium avium-intracellulare commonly produces heavy involvement of the bowel in patients with AIDS, with masses of bacteria seen within macrophages, as seen in the upper left image. Question Difficulty: Level 6

The images show disease presentations associated with Mycobacterium species infections. Which organism correlates to the disease presentation seen in the lower right image? Mycobacterium tuberculosis Mycobacterium marinum Mycobacerium scrofulaceum Mycobacterium avium-intracellulare

Blood cells or other particles are counted and sized based on changes in electrical resistance as they pass between two electrodes. The Coulter principle, developed by Walter Coulter in the late 1940 and early 1950s used "electrical impedance" to count and size particles. Cells or particles pass through two electrodes interrupting an electrical current. The number of interruptions represents the number of particles and the amount of resistance is proportional to the size of the particle. This principle is currently still being used by many manufacturers. Light scatter techniques can be used to count and categorize cells based on the degree to which light is deflected off particles. When combined with the use of stains, cells can be sorted and further differentiated by RBCs, Reticulocytes, WBC types and Platelets. Light scatter is not used in the Coulter principle for cell counting by electrical impedance. Diffraction gradient technique is not an aspect of the Coulter principle for cell counting by electrical impedance or resistance. Light transmission is not an aspect of the Coulter principle or cell counting by electrical impedance or resistance. Question Difficulty: Level 3

The impedance principle shown in this illustration is best described by the following statement: Blood cells and platelets are counted by the number of the times they scatter light as they pass in front of a mirror. Blood cells and platelets are counted utilizing a type of defraction gradient technique. Blood cells and platelets are counted by measuring the drop in transmitted light as they pass through a series of apertures. Blood cells or other particles are counted and sized based on changes in electrical resistance as they pass between two electrodes.

Chediak-Higashi syndrome Chediak-Higashi syndrome is characterized by the presence of large, fused granules in the cytoplasm of white blood cells and some tissue cells. It is an autosomal recessive disease associated with albinism, decreased immune function, and neurological complications. Toxic granulation of neutrophils can occur with infection and inflammation. These granules are darker and slightly larger than normal granules. Pelger-Huët anomaly is an autosomal dominant disorder characterized by decreased nuclear segmentation of neutrophils. The neutrophils in PHA have normal granules and function normally. Infectious mononucleosis affects lymphocytes and abnormal lymphocytes are usually present. The neutrophils usually appear normal. Question Difficulty: Level 4

The inclusions that are seen in the white cell indicated by the arrow in this image are characteristic of which of the following conditions? Chediak-Higashi syndrome Infection Pelger-Huët anomaly Infectious mononucleosis

Schistosoma mansoni Schistosoma mansoni eggs are yellowish, elongated, have a prominent lateral spine and range in size from 115 to 175 µm x 45 to 75 µm. The size, shape and lateral spine identify the parasite as Schistosoma mansoni. The eggs are typically found in stool. Schistosoma japonicum eggs are round, have a small curved rudimentary spine which may be obscured and range in size from 60 to 90 µm x 40 to 60 µm. The eggs are typically found in stool. The attached image is too large, has a large lateral spine, and is the wrong shape. Fasciola hepatica eggs are operculated and range in size from 130 to 150 µm x 60 to 90 µm. The eggs are typically found in stool. The attached image has no operculum. Ascaris lumbricoides eggs are oval, 45 to 75 µm x 35 to 50 µm. Most eggs have a bile stained mammilated outer layer. The eggs are typically found in stool. The attached image is too large and does not have the mammilated outer layer. Question Difficulty: Level 4

The intestinal parasite pictured was found in stool and measures 170 µm by 63 µm. What is the most likely organism? Schistosoma japonicum Fasciola hepatica Schistosoma mansoni Ascaris lumbricoides

Clostridium difficile Clostridium difficile is the correct response. Although the flat, gray-white spreading colonies with irregular outer margins growing on anaerobic incubated blood agar may be non-specific, the enhancement of growth on Cycloserine-cefoxitin-fructose agar (CCFA) agar provides for a presumptive identification of C. difficile. Beta hemolysis is not observed. This presumptive identification is further supported by the observation of long, slender gram-positive bacilli with production of distinctive sub-terminal spores. The biochemical reactions of positive esculin and gelatin hydrolysis are confirmatory. The presentation of antibiotic associated colitis with complication of pseudo-membanous colitis continues to be a complication among hospitalized patients. Propionibacterium acnes colonies are small, also enamel white, circular with smooth outer margins. Beta-hemolysis is not observed. Observed in gram stains are gram positive cocco-bacilli that are arranged singly, in short chains and more distinctly in diphtheroidal clusters, without production of spores. Gelatin hydrolysis is negative, and gelatin reactions are varying positive among different strains. P. acnes is most commonly considered as a contaminant when recovered in culture, but on occasion serve as the cause of skin wound and shunt infections. Actinomyces Israeli colonies on anaerobic blood agar are entire, gray-white and distinctly sunken centrally when mature, resembling a "molar tooth". Beta hemolysis is not observed. In Gram stains are observed thin, gram-positive slender branching filaments within which spores are not produced. Esculin hydrolysis is also positive, but gelatin production is negative. Cases of lymphadenitis are more commonly encountered rather than antibiotic associated colitis.. Bacteroides fragilis colonies are small, spherical, entire and non-spreading, gray and non-hemolytic on anaerobic blood agar. Small, gram negative rather than gram-positive cocco-bacilli with rounded ends are seen on gram stain. Spore production is not observed. Esculin hydrolysis and gelatin reactions are also non-discriminatory and additional biochemical assays may be required in certain instances to make a definitive identification. Question Difficulty: Level 1

The irregular-sized, gray-white colonies, with irregular margins as shown in the image to the left in the upper composite photograph were recovered from a stool specimen in a case of antibiotic associated colitis. The colonies are flat, gray-white and spreading with irregular margins. Some patients with this infection develop pseudo-membanous colitis that can be life threatening. Growth is enhanced when Cycloserine-cefoxitin-fructose agar (CCFA} is used, as seen in upper right photograph. The observation of elongated, gram positive bacilli with distinctive sub-terminal and central spores in gram-stain mounts provides for a presumptive identification. An additional key identifying biochemical reaction is the hydrolysis of esculin and gelatin. With these observations, select from the multiple choices the presumptive identification of this isolate. Propionibacterium acnes Clostridium difficile Actinomyces israeli Bacteroides fragilis

Osteoblast Osteoblasts are generally seen in clusters while plasma cells are often more diffusely distributed. Osteoblasts have delicate cytoplasm, whereas plasma cells have dense basophilic cytoplasm with a perinuclear halo. Myeloblasts have a reddish-purple nucleus with 2-3 nucleoli with a delicate, lacy evenly stained chromatin pattern. The deep blue to lighter blue staining cytoplasm is agranular. Stem cells are not morphologically recognizable. They are mononuclear cells that resemble small lymphocytes. Megakaryoblasts have scant basophilic cytoplasm with blunt cytoplasmic extensions. The nucleus of Megakaryoblasts are round with visible nucleoli and fine, distinct strands to dense reddish-purple to purple chromatin. Question Difficulty: Level 5

The large cell shown in the illustration to the right is occasionally seen in the bone marrow and can be mistaken for a plasma cell. What is this cell? Myeloblast Osteoblast Stem cell Megakaryoblast

Exserohilum species The genus name Exserohilum is derived from the nipple-like protrusion that extends from the hilar cell. These conidia are long and pencil-shaped, with multiple cells enclosed in sac-like distosepta. The conidia of Bipolaris and Drechslera species also are multi-celled with the cells separated by distosepta; however, they are more oval in outline and do not have a prominent hilar extension, as is characteristic of Exserohilum species, although blunt scar-like points of attachment may be observed. Candida species is a yeast not a dematiaceous fungus like Exserohilum species. Question Difficulty: Level 6

The long, pencil-shaped, multi-celled, thin, and smooth-walled macroconidia illustrated in this image are characteristic of which species? Exserohilum species Bipolaris species Drechslera species Candida species

Streptococcus pneumoniae The Gram stain illustrated here shows many background segmented neutrophils and a pure culture of Gram positive diplococci most consistent with Streptococcus pneumoniae. This bacterial species typically causes lobar pneumonia. Conditions that reduce host defenses, such as chronic alcoholism and malnutrition, or that compromise the mucociliary clearance mechanisms of the respiratory mucosa such as COPD and tobacco-related bronchitis predispose individuals to pneumococcal pneumonia. Klebsiella pneumoniae, Haemophilus influenzae, and Mycoplasma pneumoniae also cause pneumonia. However, K. pneumoniae and H. influenzae are Gram-negative. M. pneumoniae causes "atypical" pneumonia, as it lacks a cell wall and does not Gram stain. Question Difficulty: Level 7

The microscopic image shown here is a direct Gram stain of sputum obtained from a 70-year-old man complaining of cough, sputum production, and chest pain. This organism was alpha-hemolytic on blood agar, catalase negative, optochin ("P disk") susceptible, and bile soluble. What is the identity of this organism? Klebsiella pneumoniae Haemophilus influenzae Streptococcus pneumoniae Mycoplasma pneumoniae

Candida parapsilosis Illustrated in this photomicrograph are multiple satellite centers of growth with radial extensions of pseudohyphae, forming what have been called "spider" or "cross match stick" colonies. This cornmeal agar picture is characteristic of Candida parapsilosis. Torulopsis (Candida) glabrata does not produce pseudohyphae on cornmeal agar. Candida kefyr (pseudotropicalis) produces elongated blastoconidia that cluster in a "logs in stream" pattern whereas Candida tropicalis produces linear strands of pseudohyphae with irregularly scattered blastoconidia. Question Difficulty: Level 7

The morphology of yeasts inoculated to cornmeal agar can be helpful in making a species identification. The field of view shown in this photomicrograph is most consistent with the identification of: Candida kefyr (pseudotropicalis) Torulopsis (Candida) glabrata Candida parapsilosis Candida tropicalis

Stenotrophomonas maltophilia Darkly pigmented colonies are typically seen with bacterial species that produce pigments. Stenotrophomonas maltophilia does not produce any pigments, but can sometimes appear bluish on MacConkey agar. S. maltophilia would not appear dark on agar as shown in the image. Prevotella melaninogenica produces protoporphyrin, a dark pigment that causes colonies to turn brown to black with age. Chromobacterium violaceum produces violacein that produces a violet pigment that can appear dark, especially in older cultures. Pseudomonas aeruginosa produces a yellow-green or yellow-brown pigment called pyoverdin. Most strains also produce pyocyanin, which is a blue color. The mixture of the two pigments typically forms a green colony color. Some strains can also produce pyomelanin, which produces brown or black colonies. Question Difficulty: Level 8

The observation of darkly pigmented colonies on agar as illustrated in this photograph is somewhat of a surprise. The colonies of each of the following bacterial species may have an appearance similar to that seen here except: Prevotella melaninogenica Stenotrophomonas maltophilia Chromobacterium violaceum Pseudomonas aeruginosa

Between 10:00 A.M. and 2:00 P.M Between10:00 A.M. and 2:00 P.M is the correct response. The ovum illustrated in the photomicrograph is that of Schistosoma haematobium.These ova are excreted maximally after the first morning void, providing the optimum time for detection in the urine sediment. Immediately upon rising is an incorrect response for this exercise. The ova of Schistosoma haematobium are maximally excreted following the initial and not at the first morning void. Immediately before retiring is not the correct response for this exercise. The ova of Schistosoma haematobium are maximally excreted after the first morning void, tapering off during the daily activities. Between midnight and 2:00 A.M. is the incorrect response for this exercise.The ova of Schistosoma haematobium are maximally excreted after the first morning void and not present after a full day of activity, particularly minimal during the early hours of sleep. Question Difficulty: Level 9

The optimum time to collect a urine sample to maximize recovery of the ovum illustrated in this iodine-stained mount of urine sediment is: Immediately upon rising Prior to retiring Between 10:00 A.M. and 2:00 P.M Between midnight and 2:00 A.M

Erysipelothrix rhuziopathiae Erysipelothrix rhuziopathiae is associated with vertebrates and invertebrates including fish. It is considered an occupational hazard for fish handlers, farmers, food preparation workers and others who have direct contact with infected animals or animal products. This organism is characteristically described as a catalase negative, non-spore forming bacillus that is capable of producing H2S *********** of the TSI agar. Listeria monocytogenes is a non-spore forming Gram positive bacilli but it is differentiated from Erysipelothrix as it is catalase positive. It is also not able to produce H2S *********** of the TSI agar. Bacillus anthracis is a spore-forming Gram positive bacillus which differentiates it from Erysipelothrix. It is also associated with soil or various herbivores but not fish. Corynebacterium diphtheriae is a non-spore forming Gram positive bacillus that is catalase positive which differentiates it from Erysipelothrix. It is an opportunistic organism that is capable of colonizing the human nasopharynx but it is not associated with handling fish. Question Difficulty: Level 6

The organism pictured below was a Gram positive rod isolated from a sore on the hand of a fish market employee. It is shown on triple sugar iron agar. The organism is also catalase negative and non-spore forming. The most likely identification is: Listeria monocytogenes Bacillus anthracis Corynebacterium diphtheriae Erysipelothrix rhuziopathiae

Curvularia species Curvularia species have dark septate hyphae. The conidia are large and typically contain 4 cells, with transverse septations between the cells. The curved or boomerang effect is caused by swelling of the central cells, as shown by the arrows in the image. That central cell typically appears darker than the end cells. Bipolaris species also have dark septate hyphae. Conidiophores elongate and bend where the conidia are formed which gives a zigzag or bent appearance. The conidia are cylindrical with 3-5 septations. The conidia differ from Curvularia species because they are not curved and they do not have the central cell that swells and appears darker than the others. Exserohilum species also have dark septate hyphae and can also produce a zigzag or bent appearance from elongation of conidiophores. The conidia are long, fusiform and appear thick-walled. Each conidia cell usually has 7-11 septations. There is a dark square protrusion on each conidium called a hilum or scar of attachment. Alternaria species also have dark septate hyphae. Conidiophores and also appear zigzag. Conidia are large and have both transverse and longitudinal septations present. The conidia are also typically round at the end nearest to the conidiophore and narrow at the apex, producing a club-like shape. Question Difficulty: Level 4

The oval or curved multi-celled, dark-staining macroconidia divided by transverse septa seen in this image is characteristic of: Bipolaris species Curvularia species Exserohilum species Alternaria species

Sporothrix schenckii The lactophenol blue mount reveals tiny, ovoid microconidia, arranged in a daisy-head pattern at the tip of a straight conidiophore. This appearance is characteristic of the mold form of Sporothrix schenckii. By moving the focus up and down in a microscopic preparation, delicate hair-like attachments may be observed for each conidium. The mold form of Coccidioides immitis produces delicate, septate hyphae that may exhibit right-angle branches and racquet forms. With age, the hyphae break up into arthroconidia separated by empty or disjunctor cells, giving an alternatively staining appearance. The mold form of Blastomyces dermatitidis is characterized by septate and delicate hyphae and the production of single, smooth, pyriform microconidia, each borne on a single, short conidiophore which are said to resemble "lollipops". The mold form of Histoplasma capsulatum is characterized by spherical or pyriform smooth-walled macroconidia in young cultures that become roughened with age forming large, round, thick-walled knobby tuberculate macroconidia. Question Difficulty: Level 4

The ovoid microconidia arranged in a daisy-head pattern at the tip of a straight conidiophore, observed in the photomicrograph on the right, is characteristic of which of the following dimorphic molds? Sporothrix schenckii Coccidioides immitis Blastomyces dermatitidis Histoplasma capsulatum

Schistosoma japonicum Schistosoma japonicum is the intended response. The comparatively small size (80 um) of the ovum as shown, with its oval to spherical shape and the presence of a small knob extending from the side of the outer thin, smooth shell is distinctive for S. japonicum. The adult fluke resides in the small intestine and may invade the intestinal wall. A heavy proliferation of ova are most commonly detected in the microscopic examination of fecal specimens. Schistosoma haematobium is an incorrect response. S. haematobium ova are oval in outline and characterized by their large size (averaging 140 um) and the extension of a relatively small pointed spike from the shell at one of its narrow ends. These ova are also more commonly observed in the urine and only rarely found in the feces. Schistosoma mansoni is an incorrect response. S. mansoni ova are characterized by their large size (average of 140 um), oval outline and the distinctive large, pointed spike projecting from the side of the outer thin shell, rather than from one of the ends. Fasciola hepatica is an incorrect response. Fasciola ova are large, averaging 140 um. The outer shell is thin and smooth, but with an indistinct non-shouldered operculum at one of its narrow margins, rather than having the pointed spikes as seen with certain Schistosoma species. Question Difficulty: Level 9

The ovum shown in the high power photomicrograph, measuring 80 um, was observed in the stool specimen of a patient complaining of fever, diarrhea, and weight loss. Low grade eosinophilia of 12% was detected in a peripheral blood count. Based on these features, select the presumptive identification of this trematode species from the list of multiple choices. Schistosoma haematobium Schistosoma mansoni Fasciola hepatica Schistosoma japonicum

Basophilic stippling The intended response is basophilic stippling. Basophilic stippling represents particulate remains of an abnormal hemoglobin formed by defective heme synthesis. These particles are diffusely scattered and stained blue (see erythrocyte at tip of blue arrow), representing precipitates of ribosomes and polyribosomes (RNA). They are released in anemic conditions by the red cell proliferative response. A courser stippling may be present in thalassemia and lead poisoning. Malarial pigment is yellow-staining and found in phagocytes, not red blood cells. Pappenheimer bodies are much smaller and tend to group in pairs at the cell periphery; Howell-Jolly bodies usually occur singly at the cytoplasmic periphery in hemolytic anemia, but multiple Howell-Jolly bodies may be observed in cases of megaloblastic anemias. Question Difficulty: Level 2

The peripheral blood smear represented by the image on the right was submitted for hematologic review. The identification of the RBC inclusions shown are most likely identified as: Malarial pigment Pappenheimer bodies Howell-Jolly bodies Basophilic stippling

Staphylococcus lugdunensis In the vast majority of clinical settings, a Staphylococcus species that is coagulase positive can be identified as Staphylococcus aureus. However, microbiologists should remember that other Staphylococcus species may produce a positive coagulase test. Among the species listed here, coagulase positive strains of S. schleiferi have been recovered from human infections. Coagulase positive staphylococcal isolates from dog bite wounds should be tested for S. intermedius, some strains of which can be positive. Of the species listed, only Staphylococcus lugdunensis is always tube coagulase negative. It should be noted, however, that S. lugdunensis can produce a slide coagulase positive result (bound coagulase, or clumping factor). However, the slide test is considered obsolete. Question Difficulty: Level 6

The photograph illustrates a positive tube coagulase test (Tube A) as compared to the fluid, uncoagulated appearance of the negative control (Tube B). Each of the following Staphylococcus species may produce the reaction seen in Tube A except: Staphylococcus intermedius Staphylococcus schleiferi Staphylococcus lugdunensis Staphylococcus aureus

105 fL Most of the cells observed in the peripheral blood smear are slightly larger than normal red blood cells. This is based on the fact that the majority of the red blood cells are larger than the nucleus of the small lymphocyte in the field, which can be used as a reference for the normal size of a red blood cell. These red blood cells are classified as macrocytes. The reference interval for MCV is 80-100 fL. An MCV value below 80 fL correlates with a finding of microcytes; an MCV value above 100 fL correlates with a finding of macrocytes. 105 fL is the best option since the red blood cells are only slightly larger than the nucleus of the small lymphocyte. An MCV of 68 fL correlates with a finding of microcytes. An MCV of 82 fL correlates with a finding of normocytes. An MCV of 149 fL correlates with very large macrocytes, much larger than those seen in this peripheral blood smear. Question Difficulty: Level 4

The photomicrograph is a representative field from a peripheral blood smear. Which of the following MCV values correlates best with the peripheral blood picture? 68 fL 82 fL 105 fL 149 fL

Rhinocladiella The production of single conidia in succession both laterally and around the tip of a straight phialide is called the rhinocladiella type of sporulation, characteristic of Fonsecaea pedrosoi. Acrotheca type sporulation is also produced by F. pedrosoi; however, is characterized by the production of short chains of elliptical conidia in a circular arrangement from the tips of branching phialides. Acropetal is the term referring to a type of sporulation where chains of conidia are formed with each new daughter cell produced from the previous one, leaving the oldest cell at the base of the chain. This type of sporulation is characteristic of Aspergillus species and Penicillium species. Question Difficulty: Level 5

The photomicrograph on the right illustrates single conidia in succession both laterally and around the tip of a straight phialide. This type of sporulation, characteristic of certain species of dematiaceous mold, is called: Acrotheca Acropetal Rhinocladiella

Pyocyanin Pyocyanin is a phenazine dye that is uniquely produced by Pseudomonas aeruginosa, accounting for the blue pus that characterizes purulent infections caused by this organism. Phenylalanine is an amino acid that, upon deamination to phenyl pyruvic acid, produces a green color when reacted with ferric chloride. Fluorescein is also a pigment produced by P. aeruginosa; however, it is an iridescent yellow to the naked eye and produces a brilliant blue green fluorescence when observed with UV light. Bilverdin is an oxidative break down product of hemoglobin, which often is observed as a gray green discoloration of blood agar. Question Difficulty: Level 5

The pigment produced on the King's medium agar plate illustrated in this photograph is: Phenylalanine Fluorescein Pyocyanin Biliverdin

Serratia marcescens Phenylalanine deaminase is a key reaction for the presumptive identification of members of the Proteeae tribe, which includes the genera Proteus, Providencia, and Morganella (formerly classified in the genus Proteus) in the Enterobacteriaceae family. Therefore, from the choices listed, only Serratia marcescens does not have the capability of converting phenylalanine to phenylpyruvic acid. In addition, members of the Proteeae tribe do not ferment lactose. Serratia marcescens is a delayed lactose fermenter, and is positive for the ONPG test. Serratia species are also DNase positive, which is helpful in identification. Question Difficulty: Level 6

The positive phenylalanine deaminase reaction seen in the left tube (green pigmentation in the slant compared to the negative control on the right) may be produced by each of the following bacterial species EXCEPT: Proteus vulgaris Serratia marcescens Morganella morganii Providencia stuartii

Viral meningitis The cells presented are all mononuclear, and most appear to represent lymphocytes. Given the limited information, the most likely cause of this picture is viral meningitis which is the most common type of meningitis. While the most common type of leukocyte found in a normal centrifuged smear for a person of this age would be lymphocytes, the WBC count, combined with the symptoms do not suggest the sample is normal. A patient with bacterial meningitis would have neutrophils as the significant leukocyte population in the CSF. A patient with Alzheimer's disease is not likely have have any abnormal leukocytes changes in the CSF. Question Difficulty: Level 3

The predominant cells seen in this CSF are from a twelve-year-old female exhibiting fever, lethargy and a stiff neck. The WBC count on the sample was 2,000/microliter. The findings most likely indicate: Normal cytocentrifuged smear Viral meningitis Bacterial meningitis Alzheimer's disease

Trichophyton rubrum Trichophyton rubrum is the correct answer because the tiny microconidia are lined up in a "birds on the fence" arrangement along the hyphal strand transversing the field of view (yellow arrows). Two pencil-shaped, smooth walled macroconidia are also seen in the lower left field of view (red arrows). Epidermophyton floccosum is incorrect because of the inability of this dermatophyte to produce microconidia. Two to four-celled, club-shaped macroconidia are produced, usually in clusters of two or three. Trichophyton verrucosum is incorrect because they are irregularly arranged with little tendency to line up along the hyphae. Antler hyphae and string bean macroconidia are characteristic of this species. Microsporium audouinii is incorrect because they produce rare bizarre shaped macroconidia with few or absent microconidia. May only see terminal chlamydospores. Question Difficulty: Level 6

The profusion of tiny microconidia lining up along the hyphae in this photomicrograph is characteristic of which of the following organisms? Epidermophyton floccosum Trichophyton verrucosum Trichophyton rubrum Microsporium audouinii

Glucose oxidizer The lack of yellow conversion of either the slant or the deep of the TSI tube or both indicates that the unknown bacterial species is not a glucose or a lactose fermenter. The conversion of the open tube to a yellow color in comparison to the closed tube which remains green indicates that the bacterial species utilizes glucose oxidatively; therefore, is a glucose oxidizer. The production of a green pigment in the Pseudosel tube identifies this glucose oxidizer as Pseudomonas aeruginosa. A glucose fermenter would convert the deep portion of the TSI slant to yellow as the agar contains glucose. In addition, the closed and open tube would be yellow for the O/F Glucose indicating a fermenter. A Lactose fermenter would convert the slant and deep portion of the TSI tube to yellow indicating the organism ferments both glucose and lactose. In addition, the closed and open tube would be yellow for the O/F Glucose indicating a fermenter. An asaccharolytic organism is unable to ferment or oxidize carbohydrates. The organism would demonstrate no change in color for the TSI and no yellow pigment in either the open or closed OF tubes. Question Difficulty: Level 6

The reactions in the tubes illustrated in this exercise (reading from left to right: TSI, Pseudosel, OF glucose closed, and OF glucose open) indicate that the bacterial species in question is: Glucose fermenter Glucose oxidizer Lactose fermenter Asaccharolytic

Which of the following statements is TRUE for specific gravity measured by the reagent strip method? The reagent strip method is based on the relationship between ionic concentration and specific gravity. The reagent strip method is based on the fact that light is refracted in proportion to the amount of total solids dissolved in the urine. The reagent strip method is affected by the presence of x-ray contrast media in the urine specimen. An alkaline pH would not affect the specific gravity result using a reagent strip method.

The reagent strip method is based on the relationship between ionic concentration and specific gravity. The reagent strip method is based on the relationship between ionic concentration and specific gravity. Urine specific gravity increases as ionic concentration increases. If there were no solutes present, the specific gravity of urine would be 1.000, which is the same as pure water. Since all urine has some solutes present, a urine SG of 1.000 is not really possible. The upper limit of the test pad on a chemical reagent strip, which is typically 1.035, indicates a concentrated urine, one with many solutes with a smaller amount of water. The refractometer method is based on the fact that light is refracted in proportion to the amount of total solids dissolved in the urine. Unlike the refractometry method, the reagent strip method is NOT affected by the presence of x-ray contrast media in the urine specimen. When using the reagent strip method, an alkaline pH (6.5 or higher) would affect the specific gravity result by decreasing the reading. Question Difficulty: Level 7

Listeria monocytogenes Listeria monocytogenes produces a rectangular-shaped zone of accentuated hemolysis in the CAMP test. Because both group B, beta-hemolytic streptococci and L. monocytogenes can cause meningitis in neonates and young children, the rectangular shaped positive CAMP reaction may be a helpful clue to the correct identification in cases where the colonial morphology on primary isolation medium and gram stain features are equivocal. The Bacillus species are Gram-positive bacilli but it does not produce an enhanced zone of hemolysis on the CAMP test. Arcanobacterium (Corynebacterium) is a Gram-positive bacillus but it does not produce beta-hemolysis. Gardnerella vaginalis is a gram-positive bacillus and it produces beta hemolysis but only on agar containing human blood is used. Question Difficulty: Level 6

The red arrow in the photograph is pointing to a typical arrowhead-shaped zone of hemolysis that is produced by Streptococcus agalactiae with the CAMP test. A beta-hemolytic Gram-positive bacillus that produces a rectangular-shaped area of hemolysis as shown by the blue arrow is: Bacillus cereus Arcanobacterium (Corynebacterium) Listeria monocytogenes Gardnerella vaginalis

Pappenheimer bodies The inclusions are Pappenheimer bodies, also known as siderotic granules. In Wright stained smears the inclusions stain blue/purple. The granules would also stain positively with the iron stain Prussian blue. These inclusions can be seen post splenectomy, in hemolytic anemias, sideroblastic anemia, megaloblastic anemia, and in hemoglobinopathies. Heinz bodies can be seen in mature RBCs as a dark blue/purple inclusion of denatured hemoglobin when using a supravital stain such as new methylene blue. These inclusions can be seen in conditions such as hemoglobinopathies and G6PD deficiency. Basophilic stippling are multiple inclusions seen inside a RBC consisting of RNA. These inclusions can be seen in lead intoxication and thalassemia. Malarial ring forms are larger and distinctly ring-shaped, occupying up to 1/5 of the red cell diameter. Question Difficulty: Level 6

The red blood cell inclusions noted in the Wright stained peripheral smear to the right are called: Heinz bodies Basophilic stippling Malarial ring forms Pappenheimer bodies

Tryptophan Indole, along with pyruvic acid and ammonia, are the chemical products resulting from the deamination of the amino acid tryptophan, under the action of the enzyme tryptophanase, produced by indole-positive bacterial species. P-dimethylaminobenzaldehyde is the reagent added to the incubated media to detect the presence of indole. As stated above, pyruvate (or pyruvic acid) is one of the byproducts along with indole in the deamination of tryptophan. Peptone is added to the medium as an enrichment for bacterial growth. Indirectly, if the peptone contains large quantities of tryptophan, it could serve as a source of indole production. Nevertheless, the intended answer here is tryptophan. Question Difficulty: Level 5

The red ring at the top of the media in this tube indicates a positive indole reaction. The precursor substance in the medium from which the indole is produced is: Tryptophan p-dimethylaminobenzaldehyde Pyruvic acid Peptone

Lactose-fermenting gram-negative bacilli MacConkey agar is a selective and differential primary agar. It is selective for gram-negative bacilli as crystal violet in the agar inhibits the growth of gram-positive bacteria and fungi. It also contains lactose and a neutral red indicator allowing for the differentiation of lactose-fermenting and non-lactose fermenting bacteria. Non-lactose fermenting bacteria produce a colorless, translucent colony. Lactose-fermenting bacteria produce a pink to red colored colony due to the neutral red indicator detecting a lower pH due to acid production. MacConkey crystal violet that inhibits gram-positive bacilli and fungi from growing. MacConkey crystal violet that inhibits gram-positive bacilli and fungi from growing. Non-lactose fermenting gram-negative bacilli produce a colorless colony on MacConkey due to the lack of acid production to lower the pH. Question Difficulty: Level 2

The red/pink color of the colonies seen on this MacConkey agar plate is an indication of: Lactose-fermenting gram-positive bacilli Non-lactose fermenting gram-positive bacilli Lactose-fermenting gram-negative bacilli Non-lactose fermenting gram-negative bacilli

Paragonimus westermani Paragonimus westermani is the correct selection. Distinctive is the large size and the smooth, slightly thickened shell with a prominent shouldered operculum at one end, with absence of a knob at the opposite end. Developing larvae are observed within, retracting from the inner margin of the shell leaving a clear space. Diphyllobothrium latum is an incorrect response. D. latum ova, although of similar size, have a smooth thin shell with an indistinct, non-shouldered operculum at one of the narrow margins. The internal cleavage tends to extend to the inner margin of the shell. Clonorchis sinensis is an incorrect response. C. sinensis ova have a shouldered operculum at one end, but a distinctive knob at the opposite end. They are comparatively small, averaging 30 um and often are brown bile-stained as their origin has been within the hepatic duct system. Fasciolopsis buski is an incorrect response. F. buski ova are also large, ranging between 80 and 150 um, but have a thin, smooth shell l with an indistinct flat operculum at one end. The internal cleavage extends to the inner margin of the shell. Question Difficulty: Level 9

The relatively large ovum (100 um), as illustrated in the high-power photomicrograph, may be most commonly recovered in stool specimens from people with low grade abdominal pain and diarrhea. Ova may may also be recovered from sputum specimens as the adult worms may reside within lung pseudocysts. During periods of coughing, ova may released into the bronchi and observed in sputum samples. From the distinct features of the ova as presented in the photomicrograph, select from the multiple choices the presumptive identification. Diphyllobothrium latum Clonorchis sinensis Paragonimus westermani Fasciolopsis buski

Strongyloides stercoralis Strongyloides stercoralis is the correct response. Diagnostic is the short buccal cavity (arrow) as observed in the anterior section of the rhabditiform larva. Not observed in this photograph is the genital primordium that commonly is seen 1/3 the distance from the tail. Trichuris trichiura is an incorrect response. Trichuris larvae hatch soon after ingestion of an infective ovum and develop into adult worms in the small intestine producing eggs that are passed in stool. Ancylostoma duodenale is an incorrect response. The buccal cavities of the rhabditiform larvae of this hookworm species are long differentiating it from the short buccal cavity of Strongyloides. Necator americanus is an incorrect response. The buccal cavities of the rhabditiform larvae of this hookworm species are long differentiating it from the short buccal cavity of Strongyloides. Question Difficulty: Level 1

The rhabditiform larva shown in this image was observed in a mount prepared from a diarrheal stool specimen. This patient also complained of persistent cough and increased shortness of breath. From the list of answer choices below, what presumptive identification can be made? Strongyloides stercoralis Trichuris trichiura Ancylostoma duodenale Necator americanus

Prevotella species The production of colonies with black pigment, that also fluoresce red when viewed with a Wood's lamp, are characteristics by which Prevotella species and Porphyromonas species are separated from other anaerobic bacteria, particularly the closely related Bacteroides species. Prevotella species, which produce acids from several sugars (saccharolytic) are separated from Porphyromonas species which are asaccharolytic. Porphyromonas species, like the Prevotella species, produce black pigmented colonies that fluoresce red with Wood's lamp. But, unlike Prevotella, most of the Porphyromonas are asaccharolytic such as Porphyromonas asaccharolytica. Bacteroides species produce colonies with black pigment but they do not fluoresce. Fusobacterium species produce black pigment but do not fluoresce. Question Difficulty: Level 7

The saccharolytic anaerobe that produces red fluorescing colonies when illuminated with a Wood's lamp, as shown in this photograph, is: Porphyromonas asaccharolyticus Prevotella species Bacteroides distasonis Fusobacterium nucleatum

Phialophora verrucosum The segmented dark-staining grains seen in this photomicrograph are most commonly seen in cases of chromomycosis. Of the fungal species listed in this exercise, only Phialophora verrucosum is associated with chromomycosis and has the capability of producing the grains seen in the photograph. Although Scedosporium apiospermum may cause mycetoma and produce grains, they are soft, gray white and not segmented. Sporothrix schenckii is the agent of subcutaneous sporotrichosis, an infection that may result in granulomatous inflammation with the presence of multi-nucleated giant cells; however, grains or granules are not formed. Question Difficulty: Level 6

The segmented, dark-staining grains seen in this photomicrograph are most commonly seen in cases of chromomycosis. Which of the fungal species listed below is known to cause this disease? Scedosporium apiospermum Phialophora verrucosum Sporothrix schenckii

Streptococcus pyogenes (Group A) Streptococcus pyogenes (Group A) will have the initial observation of relatively small transparent colonies surrounded by broad zones of beta hemolysis provides for a presumptive identification of Streptococcus Group A. This identification can be confirmed by demonstrating susceptibility to bacitracin, as observed by the wide clear zone surrounding the A disc. Streptococcus agalactiae (Group B) colonies are also relatively small, transparent, and surrounded by a zone of beta hemolysis, commonly less in diameter than that observed with S. pyogenes. A presumptive identification can be made by demonstrating a positive CAMP test in which an arrow-head zone of hemolysis is observed at the interface of a beta hemolytic streptococcus with the streak line of Staphylococcus aureus. The A disk bacitracin test shows resistance. Streptococcus pneumoniae colonies are small, gray, and glistening with alpha hemolysis. The identification may require an optochin disc susceptibility instead of the bacitracin test. Streptococcus anginosus (Group F) colonies are pinpoint in size and surrounded by narrow zones of beta hemolysis. Identification can be made by demonstrating a positive Group F latex agglutination reaction. This species is commonly recovered from purulent, deep-tissue abscesses. It is resistant to the bacitracin test. Question Difficulty: Level 1

The small, transparent, gray-yellow 48 hour colonies incubated at 37°C. as illustrated in the upper photograph, are surrounded by wide zones of beta hemolysis. This culture was obtained from a throat swab of a patient with pharyngitis. The lower photograph demonstrates susceptibility of this isolate to the bacitracin "A" disc. What is the presumptive identification of this isolate? Streptococcus pyogenes (Group A) Streptococcus agalactiae (Group B) Streptococcus pneumoniae Streptococcus anginosus (Group F)

A 1:20 dilution is made for a manual WBC count. The four corner squares on both sides of a hemocytometer are counted. A TOTAL of 100 cells are counted (eight total squares). What is the white blood cell count in terms of a liter? 2.5 x 109/L 25 x 109/L 2500/L 25,000/L

2.5 x 109/L First, determine the number of WBC's from the hemocytometer as follows: WBC count = (dilution ratio x # of cells counted x 10) / (# mm2 area counted) Then: WBC count = (20 x 100 x 10) / (8) = 2500 WBC/mm3 (or 2500 WBC/µL or 2.5 x 103 WBC/µL) To find the WBC count per liter, multiply the WBC count/µL by the number of µL/L (there are 106 µL/L) So: (2.5 x 103 WBC/µL) x (106 µL/L) = 2.5 x 109 WBC/L Question Difficulty: Level 8

What is the standard deviation of the following data set, rounded to the nearest whole number? 15, 16, 18, 16, 14, 10, 20, 12, 14 3 4 5 6

3 Question Difficulty: Level 7

A technologist pipetted 200 microliters of serum in a test tube and added 5 milliliters of saline to the tube. What is the dilution ratio of serum to the total volume in the tube? 1:2.5 1:25 1:26 1:50

1:2.5 The correct answer is 1:26. There is 200 microliters of serum added to 5000 microliters of saline, for a total volume of 5200 microliters. 200 microliters of the total 5200 microliters is a dilution equaling 1:26. Question Difficulty: Level 7

The blood is diluted 1:100 and charged on the hemocytometer counting chambers on both sides. If the average platelet count from a counting chamber in one mm2 (one large square) is 68, what is the calculated platelet count? 680,000/mm3 6,800/mm3 68,000/mm3 34,000/mm3

68,000/mm3 A simple way to calculate platelet counts on the hemocytometer is to multiply the average platelet count between the two sides of the chamber by 1,000. In this case 68 x 1,000 = 68,000 platelets. The longer derivation is as follows: The standard dilution of blood for platelet counts is 1:100; therefore the dilution factor is 100. The volume of diluted blood used is based on the area and depth of the counting area. The area counted is 1 mm2 per side (since we are using the average platelet count, we only use the area of one side) and the depth factor is 10. ((Total number of cells counted x dilution factor x depth factor(mm)) / area in mm2) = platelets per mm3 Note: 103/mm3 = 103/µL = 109/L Question Difficulty: Level 7

What corrective action should be taken when rouleaux causes positive test results? A. Perform a saline replacement technique B. Perform an autoabsorption C. Run a panel D. Perform an elution

A Rouleaux may be dispersed or lessened by using the saline replacement technique. This involves recentrifuging the tube, then withdrawing serum and replacing it with 2 drops of saline. The tube is respun and examined for hemolysis. Harr, Robert R. Medical Laboratory Science Review (Page 143). F.A. Davis Company. Kindle Edition.

10^3 CFU/mL of a gram-negative bacillus There are less than ten colonies, so the colony count is 103 CFU/mL of a gram-negative bacillus is the correct answer. If it was 104, there would be more than 10 colonies and less than a hundred colonies. 105 CFU/mL would be 100 or more colonies. It is a gram-negative bacillus because it is growing on MacConkey agar. Gram-positive cocci and gram-positive rods are inhibited by the bile salts and crystal violet in MacConkey agar. Question Difficulty: Level 6

A clean catch urine was streaked to a sheep blood agar plate and a MacConkey plate with a one microliter (0.001 mL) loop. The images demonstrate what grew. How would you report the colony count and growth? 10^4 colony forming units (CFU) per milliliter (mL) of a gram-positive bacillus 10^3 CFU/mL of a gram-negative bacillus 10^5 CFU/mL of a gram-positive coccus 10^5 CFU/mL of a gram-negative bacillus

Day 7, R4s According to the charts, there was an R4s rule violation on day #7. The R4s rule applies to controls within a run. If two controls exceed 4SD, that is, if one control exceeds +2 SD and the other control (or another control, if more than 2 controls are tested) exceeds -2 SD, the run should be rejected. The 41s rule is violated when one QC level falls on the same side of the mean while exceeding (+/-) 1 SD of the mean four times, consecutively. Another way this rule may be violated is when both QC levels in two runs exceed (plus or minus) 1 SD from the mean. The 22s rule is violated when both control results in the same day exceed 2 SD from the mean. Both of the QC results will be greater than 2 SD or less than 2 SD. Another way this rule is violated is when one of the control results exceed 2 SD in a similar manner in the previous QC run or previous day. The 12s rule (also referred to as the warning rule) is violated when either of the two controls exceed 2 SD from either side of the mean. Question Difficulty: Level 8

A laboratory used the Westgard rules 22s, 41s, and R4s to determine when QC should be rejected. Referring to the Levey-Jennings plots on the right for normal (upper image) and abnormal (lower image) control values, on which day did a quality control error occur and what was the error? Day 3, 41s Day 7, R4s Day 8, 22s Day 10, 12s

6-8 microns Red blood cells that are a homogenous population of cells, 6-8 µm in diameter, will have a normal Gaussian distribution curve as shown on the right. If the red cells were 2-4 or 4-6 microns in diameter the distribution curve would be shifted to the left of normal. Red blood cells that are >8 microns will have a peak that is further to the right than the normal peak. Question Difficulty: Level 9

A medical laboratory scientist is working with a student on the teaching microscope. The student is using a microscope that has a micrometer for measurement of microscopic items. A normal red cell distribution curve for a patient is shown on the right. What should the range of red cell diameters be when the student measures the red cells with a micrometer? 2-4 microns 4-6 microns 6-8 microns 8-10 microns

Hereditary Hemochromatosis Target cells have a central area of hemoglobin surrounded by an area of pallor and a band of hemoglobin at the periphery of the cell. Their presence in disease is diverse, including severe liver disease, hemoglobinopathy, and beta thalassemia, as well as post-splenectomy, other thalassemias, and occasionally in iron deficiency anemia. In target cells, the surface area to volume ratio of the cell is increased. In a sense, target cells may be viewed in morphological contrast to spherocytes whose hemoglobin content fits tightly within the cellular membrane. Target cells may be macrocytic or normocytic. Hereditary hemochromatosis typically has normal erythropoiesis and abnormal red blood cell morphology is not usually seen. Question Difficulty: Level 6

A peripheral smear with red blood cells photographed in a typical field was submitted for review. All of the following conditions are most likely associated with the red blood cell population found here, EXCEPT: Severe liver disease Hemoglobinopathy Beta thalassemia Hereditary Hemochromatosis

None of the Above Individuals with the Bombay phenotype react as group O in forward and back type testing. However, individuals with the Bombay phenotype produce anti-H in addition to anti-A and anti-B expected in group O individuals. H substance (L-fucose) is present on the red cells of 99.99 percent of the population and is expressed to the greatest extent on the red cells of type O individuals. Therefore, it would be very dangerous to transfuse this patient with any red cells that express the H antigen. Such an individual can only receive blood from a donor of the Bombay phenotype. Question Difficulty: Level 9

A specimen from a 23-year-old female patient who is a Bombay phenotype arrives in the blood bank. You observe the following reactions upon tube testing. Which of the following statements is true? Type AB red blood cells can be transfused to this patient Type O red blood cells can be transfused to this patient in an emergency Type O NEG blood can be transfused to this patient None of the Above

When an unknown member of the Enterobacteriaceae family is recovered in primary culture, which key characteristics would lead you to suspect Klebsiella pneumoniae? Indole production Absence of motility Positive ornithine decarboxylase Positive phenylalanine deaminase

Absence of motility Klebsiella pneumoniae is characteristically nonmotile, in contrast to most other members of the Klebsiella, Enterobacter, Hafnia, and Serratia group which are all motile. Also, a key reaction for the identification of K. pneumoniae is a negative ornithine decarboxylase, as most other members of this group produce a positive reaction. The indole reaction is not discriminatory for K. pneumoniae. A positive phenylalanine deaminase reaction is most helpful in distinguishing Proteus species and Providencia species from other members of the Enterobacteriaceae, and has no discriminatory value in distinguishing K. pneumoniae. Question Difficulty: Level 7

A 36-year old woman is a known intravenous drug abuser, and gives a history of "several previous episodes of hepatitis". The laboratory workup is as follows: HBsAg- Reactive anti-HBs- Negative anti-HBc- Total Positive anti-HBc IgM- Negative anti-HAV- Total Positive anti-HCV- Positive anti-HAV IgM- Negative Which of the following diagnoses can be EXCLUDED based on laboratory data and current symptoms and history? Hepatitis D Virus (HDV) Acute hepatitis C Acute hepatitis A Chronic hepatitis B

Acute hepatitis A The positive total anti-HAV along with the negative anti-HAV (IgM) shows that the positive anti-HAV is due to IgG antibodies. This indicated that the patient has an immunity (IgG) to hepatitis A by a prior exposure to the virus. Therefore, the correct diagnosis of acute hepatitis A would not be possible. No testing was done to determine if HDV is present. Since it typically is a coinfection with HBV, which is present, it cannot be ruled out without further testing. The positive anti-HCV indicates a possible HCV infection. Additional testing must be performed to rule out a current infection. The positive reactions for HBsAg and anti-HBc point to a chronic hepatitis B infection. Question Difficulty: Level 7

The nitrite portion of the test strip can be used to: (Choose ALL correct answers) Monitor antibiotic therapy Detect a bladder infection in an early stage in pregnant women Screen individuals with recurrent infections All of the above

All of the above The nitrite portion of the test strip can be used to monitor antibiotic therapy, detect a bladder infection in an early stage in pregnant women, screen individuals with recurrent infections, and other conditions such as presence of cystitis. The test reaction on the urine chemical reagent strip pad for nitrite works by detecting when nitrite in the urine reacts with para-arsanilic acid to form a diazonium compound. This diazonium compound in turn couples with 1,2,3,4-tetrahydrobenzo(h)quinoline-3-ol to produce a pink color. Question Difficulty: Level 8

Bifidobacterium species Bifidobacterium species is the correct answer. Colonies are irregular in size, smooth, entire, convex, and non-hemolytic, ranging from gray-white to light yellow. The Gram stain appearance of the slender Gram positive bacilli with extensive branching and terminal protuberances that simulate "dog bones" is distinctive. Most species are biochemically inactive except for the fermentation of glucose and lactose. Propionibacterium acnes colonies are relatively small, gray-white, circular, convex, glistening, and opaque on blood agar after anaerobic incubation. Narrow zones of beta hemolysis may be observed. Examination of Gram stains reveal cocco-bacilli arranged singly, in short chains and more distinctly in diphtheroidal clusters without branching or formation of terminal protuberances. Biochemical reactions include fermentation of glucose; lactose is negative. Indole and catalase reactions are positive. Actinomyces Israeli colonies on anaerobic blood agar are entire, gray-white and distinctly sunken centrally when mature, resembling a "molar tooth". The Gram stain observation of thin, Gram-positive slender filaments with extensive branching that are devoid of terminal "dog bone" protuberances. Glucose is fermented; lactose is negative. Esculin is hydrolyzed and nitrates are reduced. Clostridium septicum colonies on anaerobic blood agar are flat, semi-translucent and spreading, with an outer zone of beta hemolysis. Gram-positive bacilli may be long and slender without branching or terminal protuberances, and are distinctive for the production of sub-terminal spores. Glucose and lactose are also fermented. Positive biochemical reactions include esculin hydrolysis and production of gelatinase. Question Difficulty: Level 9

Although an uncommon isolate in most microbiology laboratories, this bacterial species is included in the microbiota of the mouth and intestinal tract. The colonies on bloovd agar are irregular in size, smooth, non-hemolytic, entire, convex, and ranging from gray-white to light yellow. Distinctive is the "dog bone" appearance of branching Gram-positive bacilli as illustrated in this photomicrograph of a Gram stain. Biochemical activity is limited to fermentation of glucose and lactose. With these observations, select the presumptive identification Bifidobacterium species Propionibacterium acnes Actinomyces israeli Clostridium septicum

Yersinia enterocolitica The clinical syndrome described in the question is characteristic of the mesenteric adenitis in children and young adults caused by Yersinia enterocolitica and Yersinia pseudotuberculosis. It is not uncommon for this infection to clinically simulate acute appendicitis. Citrobacter spp. have shown wide variety of health care associated infections of the respiratory tract, urinary tract, blood, and several other normal sterile sites. It will most commonly infect hospitalized and seriously debilitated patients. Shigella species infections will show acute inflammatory colitis and bloody diarrhea. Infections with Shigella sonnei may produce watery diarrhea. Infections with enteroinvasive strains of E. coli may cause necrosis, ulceration, and inflammation of the large bowel. Question Difficulty: Level 5

An 8-year-old boy underwent a laparotomy for clinical signs and symptoms of acute appendicitis. Instead, the appendix did not appear inflamed, but the mesenteric lymph nodes were enlarged and edematous. The photomicrograph is a close-in H & E section of an area within one of the lymph nodes, showing hyperplasia and focal necrotizing inflammation. What bacterial species most likely causing this reaction? Citrobacter freundii Shigella sonnei Yersinia enterocolitica Enteroinvasive Escherichia coli

A major difference between Salmonella enterica and Shigella infections is that ONLY in salmonellosis can which of the following be observed? Animals serve as a reservoir of infection. Diarrhea becomes the major symptom. Endotoxin plays a role in the disease process. Exotoxin produces profuse, watery stools.

Animals serve as a reservoir of infection. "Animals serve as a reservoir of infection" is the correct answer because Shigella only infects humans while Salmonella is found in many animals. Both have diarrhea as the major symptom. Endotoxin is produced by all gram-negative bacteria, and exotoxin is only produced by Shigella. Question Difficulty: Level 7

A physician suspects his patient might have rheumatoid arthritis. Which of the following markers should be ordered? Antimitochondrial antibodies Anti-IgG Antineutrophilic antibodies Antimyocardial antibodies

Anti-IgG Rheumatoid arthritis commonly presents with an increase of IgM antibodies that are directed toward the Fc portion of IgG. These anti-IgG antibodies are called rheumatoid factor (RF). Patients with primary biliary cirrhosis will have an increase in antimitochondrial antibodies. Wegener's granulomatosis presents with antineutrophilic antibodies. Antimyocardial antibodies are important markers in patients who have rheumatic fever. Question Difficulty: Level 7

Acquired hemophilia A (not classic hemophilia A) may be the result of which of the following conditions? Anti-factor VIII inhibitor Factor VIII deficiency Warfarin therapy Thrombosis complications

Anti-factor VIII inhibitor Patients with acquired hemophilia A are suffering from a coagulation factor inhibitor, specifically against factor VIII. On the other hand, inherited (classic) hemophilia A is caused by a deficiency in factor VIII. Neither warfarin therapy (anticoagulant that has no effect on factor VIII) nor thrombosis complications can cause acquired hemophilia. Question Difficulty: Level 7

All of the following are likely the causes of an abnormal thrombin time (TT) EXCEPT: Fibrin split products Heparin Aspirin Dysfibrinogenemia

Aspirin The thrombin time is performed by adding thrombin to citrated plasma. Deficiencies in fibrinogen typically affect thrombin times. However, aspirin affects platelet function, and thus will not affect the thrombin time. Platelet studies would need to be performed to detect the effects of aspirin. The thrombin time is prolonged by the presence of fibrin split products, heparin, and in cases of dysfibrinogenemia, all of which affect fibrinogen levels and function. Question Difficulty: Level 7

A patient's blood gas results are: pH = 7.50, PCO2 = 55 mm Hg, HCO3- = 40 mmol/L These results indicate: A. Respiratory acidosis B. Metabolic alkalosis C. Respiratory alkalosis D. Metabolic acidosis

B A pH above 7.45 corresponds with alkalosis. Both bicarbonate and PCO2 are elevated. Bicarbonate is the conjugate base and is under metabolic (renal) control, while PCO2 is an acid and is under respiratory control. Increased bicarbonate (but not increased CO2 ) results in alkalosis; therefore, the classification is metabolic alkalosis, partially compensated by increased PCO2 . Harr, Robert R. Medical Laboratory Science Review (Page 193). F.A. Davis Company. Kindle Edition.

Catalase Streptococci are catalase negative while the Staphylococci are catalase positive, which is helpful in establishing a genus identification. CNA agar will inhibit gram negative organism, staphylococci, Bacillus spp., and coryneforms, making it useful for specimens with mixed flora. Therefore, it is a selective type of agar and not an identification agar. The specific group antigen can be demonstrated by follow-up serological tests. Detection of antigens is possible using latex agglutination or enzyme-linked immunosorbent assay (ELISA) technologies. These commercial kits have been reported to be very specific, but false-negative results may occur if specimens contain low numbers of S. pyogenes. A screening test for vancomycin susceptibility is often useful for differentiating among many alpha-hemolytic cocci. Since the hemolysis pattern is beta-hemolytic, this would not be a useful test. Question Difficulty: Level 9

Beta hemolytic colonies grew from the blood culture bottle after 18 hours incubation (see image). If the gram stain shows gram positive cocci, which of following tests would be helpful with making a preliminary identification? Catalase Regrow on CNA plate Serological testing Vancomycin susceptibility

Codocytes (target cells) are NOT an expected finding in which of the following phenotypes of beta thalassemia? Beta thalassemia minima Beta thalassemia minor Beta thalassemia intermedia Beta thalassemia major

Beta thalassemia minima Red blood cell morphology is typically normal in beta thalassemia minima. Target cells are only seen on occasion and therefore would not be an expected finding. Target cells are slightly increased in the minor phenotype, moderately increased in the intermedia phenotype, and markedly increased in the major phenotype. Question Difficulty: Level 8

The preliminary identification of bacterial species often is made based on the odor produced by colonies recovered on primary isolation media. Which of the following odors would be expected for Eikenella corrodens? Bleach Burnt chocolate Fruity Butterscotch

Bleach Eikenella corrodens exhibits a characteristic bleach or chlorine-like odor. It can also be identified by the characteristic pitting of the agar. Haemophilus species can also have a mousy or bleach-like odor. Burnt chocolate is an odor that describes Proteus species. Proteus mirabilis and most Proteus vulgaris also exhibit characteristic swarming on BAP agar. Fruity odors can be seen with a variety of gram negative bacilli including Alcaligenes fecalis, Achromobacter species, and Pseudomonas species (typically more grape-like). Butterscotch odors are seen with certain species of the Viridans Streptococci, typically Streptococcus anginosus. Question Difficulty: Level 7

Each of the following bacterial species are commonly associated with wound infections following a dog bite except? Staphylococcus intermedius Bordetella bronchiseptica Pasteurella multicida Capnocytophaga cynodegmi

Bordetella bronchiseptica Bordetella bronchiseptica is an agent causing respiratory tract infections in animals (tracheobronchitis or "kennel cough" in dogs, atrophic rhinitis in pigs, pneumonia and otitis media in rabbits and guinea pigs). Although humans, particularly those who are immunosurppressed, may acquire B. bronchiseptica respiratory infections by contact with dogs, wound infections following dog bites is not part of the clinical spectrum of this organism. In contrast, Staphylococcus intermedius, Pasteurella multicida and Capnocytophaga cynodegmi are all known to be associated with dog bites, to the point that when one of these species is recovered, either from a wound or a blood culture, an animal source must be presumed. Question Difficulty: Level 7

An aerobic gram negative coccobacillus was isolated from a nasopharyngeal swab 48 hours after culture from a 6 month old with the following culture characteristics on Bordet-Gengou agar: Small zones of beta-hemolysis Urease: positive Oxidase: negative Motility: negative The MOST probable identification of this isolate is: Pasteurella multocida Bordetella pertussis Bordetella parapertussis Bordetella bronchiseptica

Bordetella parapertussis The clinical and laboratory findings most closely match that of a Bordetella species; particularly a Bordatella parapertussis infection. Bordetella pertussis is oxidase positive but urease negative, while B. parapertussis is oxidase negative and urease positive. B. bronchosepticus is positive for both enzymes. Question Difficulty: Level 8

Which of the following markers is associated with normal mature B cell expression? CD19 CD8 CD14 C42

CD19 Normal mature B cells express CD19 (also CD20, and Kappa or Lambda). CD8 is expressed by T suppressor/cytotoxic T cells. CD14 is expressed by Monocytes. CD42 is expressed by Megakaryocytes. Question Difficulty: Level 8

Human dog bite infections may be caused by each of the following bacterial species except: Pasteurella multocida Capnocytophaga ochracea Capnocytophaga cynodegmi Neisseria weaveri

Capnocytophaga ochracea Capnocytophaga ochracea has its natural habitat in the oropharynx of humans and would not be involved in dog bite infections. All of the other bacterial species listed in this question reside in the oropharynx of dogs and other canines, and may cause human dog bite infections. Question Difficulty: Level 8

When using a flow cytometer, forward scatter measures which of the following parameters? Cell size Clonality Cytoplasmic complexity (granularity) Fluorescence

Cell size Forward scatter is directly proportional to particle or cell size. Flow cytometry can be used to determine clonality through the use of fluorescently labeled monoclonal antibodies. Side scatter is proportional to surface and cytoplasmic complexity. Cytoplasmic granules and vacuoles increase side scatter. Flow cytometers depend on the fluorescence of labeled monoclonal antibodies to help identify and quantify patient cells. These fluorescently labeled monoclonal antibodies typically bind to antigens on the surface of the patient's cells. Question Difficulty: Level 7

Iron deficiency anemia A sideroblast is a nucleated red cell that has increased iron present in its cytoplasm. The iron staining particles in the mitochondria surrounding the nucleus of the red blood cells can form ringed sideroblasts. Sideroblastic anemia may be a component of myelodysplasia. Ringed sideroblasts may appear in impaired production of protoporphyrin following drug toxicities, chronic alcoholism, lead poisoning, and the use of certain antibiotics, particularly chloramphenicol. Conditions of defective globin synthesis, including thalassemia, may promote sideroblast formation. Although the red cells in sideroblastic anemia are hypochromic, this condition is not the result of iron deficiency, marrow iron is actually overabundant. Question Difficulty: Level 6

Cells, as shown in this iron-stained bone marrow preparation, are found in each of the following conditions EXCEPT: Alcohol abuse Chloramphenicol therapy Iron deficiency anemia Thalassemia

Which one of the following drugs/drug classes is the MOST COMMON cause of drug-induced immune hemolytic anemia? Levodopa Quinidine Cephalosporins Levofloxacin

Cephalosporins Each of the drugs/drug classes listed above have been known to cause drug-induced immune hemolytic anemia, (DIIHA), although cephalosporins are the MOST COMMON cause. Cephalosporins can cause drug-induced immune hemolytic anemia when a patient produces antibodies to the particular cephalosporin drug in the presence of red blood cells. The drugs can alter the membrane appearance of the red blood cells, causing the body to mistake them as foreign. Complement becomes activated due to these antibodies; red cells are then destroyed causing hemolytic anemia. Dark urine, caused by intravascular hemolysis, is one of the most common symptoms associated with this condition. Question Difficulty: Level 7

Which one of the following statements regarding factors that affect the mobility or rate of migration in electrophoresis is NOT correct? Charged particles migrate toward the same charged electrode. The velocity of migration is controlled by the net charge of the particle. The velocity of migration is controlled by the strength of the electric field. The velocity of migration is controlled by the electrophoretic temperature.

Charged particles migrate toward the same charged electrode. Electrophoresis consists of five components: the driving force (electrical power), the support medium, the buffer, the sample, and the detecting system. Charged particles migrate toward the opposite charged electrode. The velocity of the migration is controlled by the net charge of the particle, the strength of the electric field, chemical and physical properties of the supporting medium, and the electrophoretic temperature. Question Difficulty: Level 7

Aspergillus species Aspergillus species is the correct selection. A suggested genus identification of Aspergillus can be made if distinctive uniform septate hyphae are observed, characterized by dichotomous branching at 45 degree angles. Curvularia species is incorrect. Curvularia species is a cause of phaeohyphomycosis and yellowish to brown hyphal elements with or without budding cells can be seen in tissue specimens. However, since other species can cause phaeohyphomycosis, a fungal culture must be performed for fungal identification. Penicillium species is incorrect because this species forms regular transparent septate hyphae without dichotomous branching. Microsporum canis is incorrect because this superficial dermatophyte does not have hyphae that would be observed in tissue sections. Question Difficulty: Level 5

Choose the fungi that may be identified to a genus level, when the fungal structures that are seen in this photomicrograph are present in tissue sections. Curvularia species Aspergillus species Penicillium species Microsporum canis

Each of the tests below are appropriately matched with a chemical responsible for producing a positive result, EXCEPT: ONPG - ß-galactosidase Citrate - alpha naphthol Indole production - dimenthylaminobenzaldehyde H2S production - sodium thiosulfate

Citrate - alpha naphthol The correct answer is citrate - alpha naphthol. Simmon's citrate agar is based on the principle that if an organism can utilize citrate as its sole carbon source, it will produce alkaline products which will convert the bromothymol blue indicator to a blue color. Alpha naphthol is used in the Voges-Proskauer test. In the ONPG test, an organism will produce ß-galactosidase if it's able to degrade lactose. Indole production is detected by observing a red color when dimethylaminobenzaldehyde or tetramethylaminobenzaldehyde are added. H2S production requires a sulfur source. Sodium thiosulfate is commonly used. Question Difficulty: Level 8

The antecubital area is usually the site used for venipuncture because of its accessibility. Which of the following veins is NOT located in the antecubital area. Median cubital vein Femoral vein Basilic vein Cephalic vein

Femoral vein The femoral vein is located in the groin area along with the femoral artery. It is not used for routine venipuncture. The remaining three veins are located in the antecubital area of the arm as shown in the image. Question Difficulty: Level 2

Which of the following is the bacterial agent associated with antibiotic-associated pseudomembranous colitis? Campylobacter jejunii Clostridium difficile Shigella dysenteriae Bacillus cereus

Clostridium difficile Clostridium difficile is the causative agent of antibiotic-associated pseudomembranous colitis. The diagnosis of this infection is based on clinical symptoms and the detection of a C. difficile cytotoxin. Campylobacter jejuni produces a characteristic bloody diarrhea with white blood cells after the consumption of infected food sources. Culture detection is sufficient for diagnosis. Shigella dysenteriae produces dysentery with white blood cells. It is associated with contaminated water. Bacillus cereus produces watery diarrhea with white blood cells and vomiting. The infection is associated with the consumption of a pre-formed toxin from a food source such as meats, vegetables, and rice. Question Difficulty: Level 7

Which of the following organisms causes Q fever? Coxiella burnetii Anaplasma spp. Orientia tsutsugamushi Rickettsia rickettsii

Coxiella burnetii Q fever, an acute systemic infection affecting the lungs, is caused by Coxiella burnetii. Anaplasma spp. causes human granulocytic anaplasmosis. Orientia tsutsugamushi causes scrub typhus. Rickettsia rickettsii causes Rocky Mountain spotted fever. Question Difficulty: Level 8

Match the complications that are most likely to be associated with each of the two yeast diseases that are listed in the drop-down box: Cryptococcosis, Candidiasis, Cryptococcosis Meningoencephalitis, Esophagogastritis, Cranial nerve palsy, Onychomycosis, Renal abscess, Thrush

Cryptococcosis Meningoencephalitis Candidiasis Esophagogastritis Cryptococcosis Cranial nerve palsy Candidiasis Onychomycosis Candidiasis Renal abscess Candidiasis Thrush Although there is crossover in the complications that may occur during the disease processes of both candidiasis and cryptococcosis, central nervous system involvement including meningoencephalitis and cerebral nerve palsies are more likely to occur in cryptococcosis. All of the other items listed are more likely to occur in candidiasis, although not to the total exclusion of occasionally occurring in cryptococcosis as well. Esophagogastritis, onychomycosis and thrush are common complications of candidiasis and would be extremely unusual in cryptococcosis. The urinary tract can be involved in cryptococcosis and organisms can frequently be recovered in the urine. However, in most instances the lesions are occult in which cryptococcal cells may be seen within the glomeruli or tubules, but with little inflammation. Hematogenous spread of the yeast cells of Candida albicans to the kidneys commonly results in foci of suppurative inflammation in the cortex and medulla, that can progress to abscess formation. Question Difficulty: Level 8

The most common screening test for Hb S, the hemoglobin solubility test, is based on which of the following principles? Decreased solubility of deoxygenated Hb S in solution produces visible turbidity. The reduction of iron from the ferrous to the ferric state produces visible turbidity. Increased solubility of deoxygenated HbS in solution produces visible turbidity. The fact that any unstable hemoglobin will result in visible turbidity.

Decreased solubility of deoxygenated Hb S in solution produces visible turbidity. The insolubility of hemoglobin S when combined with a reducing agent will result in visible turbidity which is considered a positive result. This test does not differentiate Hb S disease from Hb S trait. The reduction of iron results in ferrous (Fe+2 ) iron and not the ferric (Fe+3 ) state. Increased solubility would not result in turbidity. There are several other variants (i.e. Hb C-Harlem, Hb C-Memphis) that will give a positive solubility, but there are many unstable variants that will be negative. Question Difficulty: Level 7

Which of the following represent other hemoglobin gene loci that occur on the same chromosome as the beta chain loci? Alpha and delta Delta and gamma Gamma and zeta Zeta and epsilon

Delta and gamma The loci for globin chain production are found on Chromosomes 11 and 16. Alpha and zeta are both found on chromosome 16. Beta, delta, epsilon, and gamma are all found on chromosome 11. Genes for the production of alpha chains are found on chromosome 16, and genes for the production of delta chains are found on chromosome 11. Genes for the production of gamma chains are found on chromosome 16, and genes for the production of zeta chains are found on chromosome 11. Genes for the production of zeta chains are found on chromosome 11, and genes for the production of epsilon chains are found on chromosome 16. Question Difficulty: Level 7

Which of the following is the most common method for diagnosing malaria? Serological testing Polymerase chain reaction (PCR) techniques Demonstration of the organism in peripheral blood Biochemical reactions

Demonstration of the organism in peripheral blood Diagnosis of malaria often requires thick smears to screen for the presence, as well as conventional thin blood smears to identify the species of Plasmodium. Today, Giemsa stained smears are still the specimen of choice for diagnosing malaria. Though serological testing and PCR are useful in ruling out malaria as a cause of fever of unknown origin and confirming malarial speciation, respectively; they are often not necessary. Biochemical reactions are useful for speciation of bacteria, not sporozoa like Plasmodium. Question Difficulty: Level 3

A two-year old male patient has the following hemogram results: Hgb = 6.7g/dL Hct = 20% Platelets = 355 x 109/L RBC = 3.0 x1012/L WBC = 8.75 x 109/L Differential = 6% eos, 20% segs, 68% lymphs, 6% monos Which of the following is the MOST likely diagnosis? Dietary iron deficiency Idiopathic thrombocytopenia Lymphocytic leukemia Lead poisoning

Dietary iron deficiency Iron deficiency anemia is the most likely diagnosis because the RBC, Hct, and Hgb are all very low. Idiopathic thrombocytopenia can be ruled out since the platelet count is normal. Lymphocytic leukemia can also be ruled out because the WBC is normal. Finally, lead poisoning is ruled out since this condition does not usually cause severe anemia. Question Difficulty: Level 7

Which one of the following is an immunochemical electrophoresis that uses antisera and quantitates an unknown antigen? Southern blotting Immunofixation electrophoresis Two-dimensional electrophoresis Electroimmunoassay electrophoresis

Electroimmunoassay electrophoresis Immunofixation electrophoresis and electroimmunoassay are two types of immunochemical electrophoresis. In electroimmunoassay electrophoresis (also known as rocket immunoelectrophoresis), peaks are created at the precipitin line proportional to the concentration of antigen in the sample. The height of each peak is compared to standards of known antigen concentration in order to quantify the antige in the sample. Immunofixation electrophoresis uses antisera but only identifies the presence or absence of an unknown, a qualitative measurement. Question Difficulty: Level 7

ESBL- Extended-Spectrum Beta Lactamase with chromosomal AmpC The correct answer is ESBL with chromosomal AmpC. All Enterobacters are AmpCs as demonstrated for this organism, with cefoxitin being resistant and cefepime susceptible. AmpCs hydrolyze all penicillins (not seen here), cephamycins (cefoxitin), monobactams (aztreonam) and cephalosporins (except cefepime). AmpC beta-lactamases can be inducible or constitutive. With inducible production, the enzyme is produced at low levels unless the organisms is exposed to inducing agents. Induction is a reversible mechanism so if the inducing agent is withdrawn, the enzyme production returns to previous low levels. Constitutive cephalosporinase production is not reversible. Keyholes are extended areas of clearance between cefotaxime and ceftazidime clav as well as cefepime and ceftazidime-clav, indicating an ESBL. A clavulanic effect is also observed between ceftazidime and ceftazidime-clav. All cephalosporins that test susceptible(as seen with cefepime)should be modified to resistant if the new February 21015 CLSI Breakpoints is used. This post-analytic comment should be added to the susceptibility reports upon recovery of all E. cloacae isolates: "This organism is known to possess inducible beta-lactamases. Isolates may become resistant to all cephalosporins after initiation of therapy. Avoid beta-lactam-inhibitor drugs." There is no carbapenem effect so this organism is not a KPC. Ertapenem and imipenem were not hydrolyzed. KPCs hydrolyze all penicillins, cephalosporins, cephamycins, carbapenems and monobactams. Question Difficulty: Level 9

Enterobacter cloacae colonies were isolated from a blood culture taken from a 45-year-old woman undergoing chemotherapy for breast cancer. Observe this Kirby-Bauer susceptibility plate and the result report form for this organism. From the multiple choices, identify the resistance mechanism (if any) that this organism demonstrates. KPC - Klebsiella pneumoniae Carbapenemase ESBL- Extended-Spectrum Beta Lactamase with chromosomal AmpC None of the above

Which of the following factors is known as Hageman factor? Factor X Factor XII Factor V Factor VII

Factor XII Factor XII is known as Hageman factor. Factors X, V, and VII are known as Stuart factor, proaccelerin, and proconvertin or stable factor, respectively. Question Difficulty: Level 7

Which of the following is used to analyze risk and highlight aspects of a process that should be targeted for improvement? Voice of customers (VOC) Quality control plan (QCP) Supplier, inputs, process, outputs, and customer (SIPOC) diagram Failure mode and effects analysis (FMEA)

Failure mode and effects analysis (FMEA) FMEA is used primarily to evaluate a process. This tool is used to analyze risk and highlight aspects of a process that should be targeted for improvement. VOC is a tool that can be used to understand what the customers want from the customers' perspective. It is used to identify key drivers of customer satisfaction. A quality control plan (QCP) is a written document describing the practices and procedures performed by your laboratory to reduce the chance of possible failures and errors in test processes. The SIPOC diagram is used in Six Sigma to help identify the key elements in a process: supplier, inputs, outputs and customer. This is a high-level map that encourages system thinking by focusing the team to see the process through the customer's eyes. Question Difficulty: Level 8

Each of the following characteristics will differentiate between Listeria monocytogenes and Erysipelothrix rhusiopathiae except: Hydrolysis of esculin Motility Catalase Fermentation of glucose

Fermentation of glucose In order to differentiate between the two organisms, there should be one organism that has a positive reaction to the biochemical, and one that has a negative reaction to the biochemical. Both Listeria monocytogenes and Erysipelothrix rhusiopathiae ferment glucose, so this testing would not differentiate between the two organisms. Listeria monocytogenes is motile at room temperature incubation (umbrella shaped motility), hydrolyzes esculin and is catalase positive. Erysipelothrix rhusiopathiae is non-motile, does not hydrolyze esculin, and is catalase negative. Each of these biochemicals provides a positive and negative result with the respective organisms and thus can differentiate the two. Another way to differentiate the two organisms is H2S production. Erysipelothrix rhusiopathiae is H2S positive and Listeria monocytogenes is H2S negative. Question Difficulty: Level 7

Frame A The correct answer is frame A. In Frame A are tear drop cells, a red blood cell morphology highly associated with myelofibrosis. In Frame B, burr cells are present, representing artifacts of smear preparation or true burr cell presentation accompanying uremia. In Frame C, schistocytes are present, which is a common marker in disseminated intravascular coagulation. ln Frame D, acanthocytes are present, which accompany lipid disorders, including abetalipoproteinemia. Question Difficulty: Level 7

From the peripheral blood smears shown in the images to the right which image most likely corresponds with the blood smear that would be found from a patient with myelofibrosis? Frame A Frame B Frame C Frame D

Neisseria species Neisseria species is the correct answer because gram-negative cocci that occur in pairs with their adjacent sides flattened are typical of Neisseria species, including Neisseria meningitidis and Neisseria gonorrhoeae. The bacteria in the gram stain that is represented by the image is Neisseria gonorrhoeae. Streptococcus pneumoniae is incorrect because this species is gram positive cocci in pairs and chains. They appear oval in shape and are known as lancet-shaped gram positive cocci. Staphylococcus species is incorrect because Staphylococcus species are gram positive cocci in clusters. Micrococcus species is incorrect because Micrococcus species are large gram positive cocci that can appear in pairs, tetrads, and clusters. Question Difficulty: Level 2

Gram-negative cocci that occur in pairs with their adjacent sides flattened, giving them a "coffee bean" appearance (indicated by the arrows in the image), are typical of which of the following bacteria? Streptococcus pneumoniae Neisseria species Staphylococcus species Micrococcus species

Also known as the "Right to Know" law, which of these OSHA regulations first dealt with specific information related to the contents of chemicals used in the workplace? Blood Borne Pathogens 1910.1030 Formaldehyde 1910.1048 Occupational Exposure 1910.1450 Hazard Communication 1910.1200

Hazard Communication 1910.1200 According to OSHA, Hazard Communication 1910.1200 has the purpose of ensuring that the hazards of all chemicals produced or imported are evaluated, and that information concerning their hazards is transmitted to employers and employees. Question Difficulty: Level 7

With the exception of beta thalassemia minima, which hemoglobin is decreased in beta thalassemia? Hb A Hb A2 Hb F Hb S

Hb A Hemoglobin A is decreased in beta thalassemias,with the exception of beta thalassemia minima. Hb A2 is increased in beta thalassemia and increased levels of Hb A2, usually between 3.5-7%, where normal levels are always less than 3.5%. Hb F is produced in utero by the fetus and does not play a role in beta thalassemia. Hb S is an abnormal hemoglobin and is typically associated with sickle cell anemia, but may also be present in beta thalassemia with hemoglobin S where it is increased. Question Difficulty: Level 7

The usual radiation source in atomic absorption instruments is the: Xenon arc Deuterium lamp Tungsten lamp Hollow cathode lamp

Hollow cathode lamp Hollow cathode lamps are commonly used as the radiation source in atomic absorption spectroscopy. Inside the lamp, which is filled with argon or neon gas, is a cylindrical metal cathode containing the metal for excitation, and an anode. After a high voltage is applied across the anode and cathode, gas particles are ionized and the gaseous ions acquire enough energy to eject metal atoms from the cathode. Xenon, deuterium, and tungsten are continuum sources that are widely used in the clinical laboratory. Deuterium provides UV radiation in analytical spectrometers, Question Difficulty: Level 7

Intracellular gram-negative diplococci The most complete report is "Intracellular gram-negative diplococci." It is important to state that the organisms are located intracellularly. If this sample were collected from a male with urethritis, the appearance of gram-negative diplococci inside polymorphonuclear leukocytes is diagnostic. Stating just gram-negative, gram negative cocci, or intracellular gram-negative cocci does not give a complete and accurate depiction of the Gram stain and could be misleading in some clinical scenarios. Question Difficulty: Level 4

How should the organisms that are indicated by the arrows be reported? Gram-negative organisms seen Gram-negative cocci Intracellular gram-negative cocci Intracellular gram-negative diplococci

The bone marrow in alpha thalassemia major usually demonstrates: Normoplasia Hypoplasia Aplasia Hyperplasia

Hyperplasia The bone marrow in alpha thalassemia major often demonstrates erythroid hyperplasia, as it tries to compensate for the anemia that is present. Erythroblasts appear abnormal with minimal cytoplasm, uneven membranes, and basophilic stippling. Normoplaisa (normal), hypoplasia (decreased), or aplasia (absent) erythroid hematopoiesis are not commonly seen in the bone marrow of alpha thalassemia major patients. Question Difficulty: Level 7

Rapid urease

Illustrated in this photomicrograph of a gastric biopsy specimen are a few thin, curved and S-shaped bacteria (arrows). This picture is suspicious for Helicobacter pylori. An additional test helpful in confirming this identification is: Indoxyl acetate Rapid urease Hippurate hydrolysis Growth at 42° C

Artifact The correct answer is artifact. Although this suspicious form resembles an intestinal nematode larva, the internal structures necessary for it to function as well as to identify it as a parasite are lacking. Hookworm rhabditiform larvae are rarely seen in stool, but if observed, have a large buccal cavity. Strongyloides rhabditiform larva have a short buccal cavity and a prominent genital primordium. Strongyloides filariform larvae are generally a cause of reinfection when the rhabditiform larva hatch while still in the intestine and migrate into the circulation, thus they are not normally found in stool. Question Difficulty: Level 3

Identify this form found in a stool sample: Artifact Hookworm rhabditiform larva Strongyloides rhabditiform larva Strongyloides filariform larva

Patients with which of the following conditions would benefit most from washed red cells: Warm autoimmune hemolytic anemia Cold autoimmune hemolytic anemia IgA deficiency with anti-IgA Multiple red cell alloantibodies

IgA deficiency with anti-IgA Washing not only reduces the number of leukocytes and platelets that are often responsible for febrile reactions, but also eliminates plasma proteins, such as IgA. Warm autoimmune hemolytic anemia, cold autoimmune hemolytic anemia, and alloantibodies all involve patient antibody binding to antigens on the donor red blood cells. Washing would not remove the antigens from the red blood cells so washing has no advantage in these cases. Question Difficulty: Level 7

For transfusion services in the United States, which of the following incidents must be reported to the Food and Drug Administration (FDA) because of a biological product deviation? Incident A: A unit was issued with an incorrect expiration date. The expiration date was incorrectly marked as one day earlier than the actual expiration date. Incident B: A nurse in ICU misidentified the patient and initiated the transfusion of Rh positive blood to an Rh negative patient. Incident C: The wrong specimen was used to crossmatch a unit and the unit was issued. Incident D: Donor reports information that is disqualifying based on revised questions. Previous collected units were distributed.

Incident C: The wrong specimen was used to crossmatch a unit and the unit was issued. According to 21 CFR 606.171, an event is reportable, if it occurred while the product was under the control of the transfusion service, is a deviation of standard practice that affects the safety, purity or potency of the product, and if the unit was issued. Incident C is reportable to the FDA because of a biological product deviation. In this case, an error was made in the blood bank and the unit was issued. It is reportable regardless of the harm to the patient. In Incident A, the outdate was shortened; therefore, there is no concern for the safety, purity or potency of the product. This is not reportable. Incident B did not occur within the jurisdiction of the blood bank and is not reportable as a biological product deviation. There was no safety, purity or potency issue related to the product issued by the transfusion service. However, if the patient dies as a result of a transfusion reaction, the FDA must be notified, but not through the biological product deviation reporting process. Incident D is not a qualifying event because the donor would have been acceptable with previous guidelines in place and did not have a change in previously-qualifying information. Question Difficulty: Level 9

What may prevent the detection of lupus anticoagulant in a plasma sample if the blood used for testing is not centrifuged for a sufficient time? Residual red blood cells in the plasma sample Increased platelets in the plasma sample Residual white blood cells in the plasma sample Centrifugation time would not affect the detection of lupus anticoagulant in a plasma sample

Increased platelets in the plasma sample Increased platelets in the plasma could prevent the detection of lupus anticoagulant (antiphospholipid antibody). Platelet membranes contain a high content of lipids that can cause the antiphospholipid antibody to bind to the platelet membrane, thereby neutralizing the antibody so that it is not detected. Blood specimens should be centrifuged for a sufficient time to ensure a residual platelet concentration of less than 10 x 109/L. Although red or white blood cells do have phospholipid membranes, they do not contain a high content of lipids in their membranes and would not specifically affect the lupus anticoagulant test. Question Difficulty: Level 7

Which of the following statements is true regarding cardiovascular disease and adipose tissue? Inflammatory cytokines, synthesized and released by adipose tissue, contribute to the development of cardiovascular disease. Increased synthesis and secretion of PAI-1 in metabolic syndrome contributes to cardiovascular disease by increasing blood pressure. Obesity in metabolic syndrome contributes to the development of cardiovascular disease by increased synthesis and secretion of adiponectin. None of the above

Inflammatory cytokines, synthesized and released by adipose tissue, contribute to the development of cardiovascular disease. Adipose tissue secretes a large number of pro- and anti-inflammatory adipokines. Adipokines modulate inflammation and insulin resistance. The expression of pro-inflammatory adipokines is enhanced with obesity, which induces insulin resistance. The increase in inflammatory cytokines and the abnormal lipids and lipid levels often present in metabolic syndrome increase the risk of cardiovascular disease. Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of fibrinolysis, the physiological process that degrades blood clots. PAI-1 is increased in obesity, is associated with insulin resistance, and is an early inflammatory predictor of type 2 diabetes. Adiponectin is synthesized and secreted almost exclusively by the adipocytes and is an anti-inflammatory cytokine. Levels of adiponectin are decreased in weight gain, obesity, and in those who are insulin resistant. Question Difficulty: Level 7

What is the mechanism that causes megaloblastic anemia? Defective stem cell production Interruption of hemoglobin production Interruption of DNA Synthesis Interruption of development of precursor cells

Interruption of DNA Synthesis Interruption of DNA synthesis results in the development of a megaloblastic anemia. Defective stem cell production results in the development of aplastic anemia. Interruption of hemoglobin production results in thalassemia. Interruption in the development of precursor cells is an anemia that is caused by chronic renal disease. Question Difficulty: Level 7

Which one of the following conditions is NOT associated with hereditary spherocytosis? Increased osmotic fragility An MCHC greater than 37% Intravascular hemolysis Extravascular hemolysis

Intravascular hemolysis Hereditary spherocytosis(HS) is a genetic defect in a RBC cytoskeletal or transmembrane protein which results in a loss of membrane protein causing spherocytes to form. Intravascular hemolysis occurs inside the blood vessels releasing hemoglobin into the plasma. Intravascular hemolysis does not occur when a patient is suffering from hereditary spherocytosis. Instead macrophages in the spleen and liver remove the spherocytes from circulation; a process called extravascular hemolysis. The Mean Cell Hemoglobin Concentration, MCHC, is a measure of the average relative hemoglobin concentration in the RBC and is expressed in grams/deciliter (g/dL). A typical reference range for MCHC is 32-36 g/dL. In hereditary spherocytosis, the MCHC is increased due the decreased surface to volume ratio of the red cell. Spherocytes also have increased osmotic fragility. The osmotic fragility test uses different solutions of NaCl and measures the susceptibility of a patient's red cells to hemolyze in decreased NaCl (hypotonic) solutions. Due to their inability to respond to the osmotic changes that occur in hypotonic solutions, spherocytes will hemolyze at a higher NaCl concentration than normal RBCs. This is increased osmotic fragility. Question Difficulty: Level 7

All of the following are usually increased in alpha thalassemia EXCEPT? Iron binding capacity Percent iron saturation Lactate dehydrogenase Bilirubin

Iron binding capacity The iron binding capacity is normal or even decreased in alpha thalassemia because iron may remain in excess as inadequate amounts of hemoglobin are being formed. Percent iron saturation is increased because iron it is not being incorporated into hemoglobin as normal. Additionally, the anemia experienced in alpha thalassemia is treated with (multiple) transfusions. Lactate dehydrogenase and bilirubin are both increased due to increased hemolysis (removal of abnormal erythrocytes). Question Difficulty: Level 7

Bacillus anthracis Bacillus anthracis is the correct response. It is important to immediately recognize the large, flat, spreading, non-hemolytic gray-yellow colonies on blood agar with a ground-glass surface and irregular margins with comma-shaped extensions. The presumptive identification of Bacillus anthracis is supported by the peak like extension from the tip of an inoculating wire and the long chains of elongated, spore-bearing gram positive bacilli arranged in long branching chains. With these observations, the culture should be immediately referred to the local state laboratory to confirm this anthrax-producing agent of bio-terrorism. Corynebacterium jeikeium colonies are small, 0.5 - 1.0 mm, gray white, without peripheral extensions and are non-hemolytic. Microscopically are observed short Gram-positive bacilli arranged in V-forms or palisades, never in chains. Spores are not produced. Lactobacillus species colonies on sheep blood agar after 24 hours incubation are small, gray white, convex, and smooth without peripheral extensions. Light alpha hemolysis may be observed. Microscopic examination of Gram stained mounts reveal long, slender, non-spore forming positive bacilli also arranged in chains. Listeria monocytogenes colonies growing on blood agar are small, smooth, gray-white, and surrounded by narrow zones of soft beta hemolysis. Microscopically are observed small non-spore forming gram-positive bacilli with rounded ends lying singly in loose diphtheroidal-like clusters. The CAMP test is positive but with rectangular external rather than inverse zones of hemolysis. Question Difficulty: Level 1

It is important to make a presumptive identification of the large, flat, spreading, gray-white, non-hemolytic colonies, with comma-like extensions growing on blood agar, as illustrated in the upper photograph. When mucoid colonies are observed, peak-like extensions may be observed when the colony is lifted with an inoculating loop (lower left image in the composite). Long, spore-bearing, Gram positive bacilli, often in straight and branching chains, are observed on Gram stain. Based on the results given, select the presumptive identification of this isolate. Corynebacterium jeikeium Bacillus anthracis Lactobacillus species Listeria monocytogenes

In order to identify an isolate as Yersinia enterocolitica, it must be lysine-negative and demonstrate which of the following? K/A on Kligler's iron agar Agglutinate in O polyvalent antisera Grow on XLD agar as a red colony with black centers Produce gas from glucose

K/A on Kligler's iron agar The correct answer is K/A on Kligler's iron agar. Although Y. enterocolitica is A/A on triple sugar iron agar (TSIA), it ferments sucrose which is not present in Kligler's iron agar. Antisera typing is required to identify Salmonella and Shigella but not Y. enterocolitica. Salmonella is a red colony with black centers on XLD. Y. enterocolitica is not identified on the basis of gas production. Question Difficulty: Level 7

All of the following are sites of active hematopoiesis in the adult EXCEPT: Skull Ribs Liver Pelvis

Liver Except for the liver, each of the sites listed above are areas where hematopoiesis occurs in adults. Yolk sac, liver, and spleen are sites of hematopoiesis during the fetal months. Question Difficulty: Level 8

A patient initially has a prolonged PT. After reviewing the patient's case and laboratory findings, the physician administers intravenous vitamin K. The repeat PT results are normal after 24 hours of vitamin K therapy. What clinical condition is MOST likely to produce these results? Liver disease Factor XI deficiency Fibrinogen deficency vWF deficency

Liver disease In liver disease, vitamin K deficiency results from decreased bile salt synthesis, which leads to impaired vitamin K absorption and deficiency. Vitamin K dependent blood coagulation proteins include II, VII, IX, X, and proteins C, S, and Z. Factor XI, fibrinogen, and vWF are not vitamin K dependent, thus treatment with vitamin K would have no effect on those deficiencies. Question Difficulty: Level 7

Which of the following species of Mycobacterium might be associated with contamination of the hot water system in large institutions such as hospitals? M. xenopi M. ulcerans M. marinum M. haemophilum

M. xenopi The optimum growth temperature of M. xenopi is 42°C, which enables it to survive and replicate as an environmental contaminant in hot water systems. Human infections caused by M. xenopi are very rare but have been reported. The majority of clinically significant Mycobacterium species grow optimally at 37°C or lower. Question Difficulty: Level 8

Nucleus A Nucleolus B Cytoplasm C Generally we consider 2 compartments in the cell when detecting autoantibodies in systemic rheumatic disease: the nucleus, indicated by letter A and cytoplasm, indicated by letter C. Staining of the nucleus includes staining inside the nucleoli, indicated by letter B. Question Difficulty: Level 2

Match each letter in this image of a tissue cell that is used as a substrate in ANA testing to the structure that it is indicating. Nucleus Nucleolus Cytoplasm A B C

Bacillus anthracis Bacillus anthracis is a large, gram-positive rod with square ends appearing in single and short chains. Yersinia pestis is fat, gram-negative rod in single or short chains with bipolar staining. Francisella tularensis is a very tiny, weakly stained gram-negative coccobacilli and it is difficult to see individual cells. Brucella species is a very small, gram-negative coccobacilli that may stain gram-positive. The individual cells are evident. Question Difficulty: Level 7

Match the Gram-stained image to the organism it MOST closely represents. Bacillus anthracis Yersinia pestis Francisella tularensis Brucella species

Monotrichous A Peritrichous B Amphitrichous C A- Monotrichous B- Peritrichous C- Amphitrichous Question Difficulty: Level 6

Match the illustrations with their correct description: Monotrichous Peritrichous Amphitrichous

What is the rare phenotype found exclusively in male patients that is caused by X-linked inheritance from a carrier mother, often demonstrating a chronic but well-compensated anemia as well as muscle and nerve disorders? Fy (a- b-) McLeod Jk (a- b-) U-

McLeod The correct answer is the McLeod phenotype, which also is indicated by a lack of the Kx and Km antigens, depressed expression of other Kell Blood Group antigens, and may be associated with X-linked chronic granulomatous disease (but this association is not always present). The Fy (a- b-) phenotype is found primarily in the African American population and is associated with resistance to malaria caused by P. vivax. The Jk (a- b-) phenotype is a very rare phenotype, but when present, is most often found in the Polynesian population. The U- phenotype is very rare and only exists in individuals who are both S- and s-. Question Difficulty: Level 9

Which assay, using 24-hour urine, is considered the BEST single screening test for pheochromocytoma? Catecholamines Vanillylmandelic acid (VMA) Homovallic acid (HVA) Metanephrines

Metanephrines The most reliable screening tests for diagnosis of pheochromocytoma is measurement of plasma-free fractionated metanephrines and urinary fractionated metanephrines. Pheochromocytoma is an adrenal or extraadrenal neoplasm that secretes catecholamines. Patients with pheochromocytoma often exhibit persistent and paroxysmal hypertension. Urinary free catecholamines, and vanillylmandelic acid are also elevated. Question Difficulty: Level 7

Peripheral blood smear findings of microcytes or microspherocytes, target cells, and nucleated red blood cells should be reported. Macrocytes are not present. The MCV result correlates with a finding of microcytes. A few red blood cell fragments may be seen, but sickle cells are not present. The inclusion that is noted in this field is a cell nucleus in a nucleated red blood cell and not a blood parasite. Homozygous hemoglobin E is common in Southeast Asia and presents with very mild anemia and seldom requires transfusion. Over 30 million people in the world are HbE carriers, making this abnormal hemoglobin almost as common as HbS. Hemoglobin E is uncommon in North America and in Europe, but with changing immigration patterns, Hb E cannot be ignored. Clinically, a very important and severe syndrome is hemoglobin E/beta thalassemia in which there is hemolysis requiring repeated transfusions. The patient would have a severe anemia, low MCV, and high RBC. This is characteristic of Hgb E/beta thalassemia. Question Difficulty: Level 5

Microcytes (microspherocytes), target cells, nucleated red blood cells Macrocytes, target cells, nucleated red blood cells Sickle cells, target cells, and malarial parasites Microcytes, target cells, and malarial parasites

Which of the following situations suggest a traumatic tap occurred? More blood is in tube 1 than tubes 2, 3 or 4. Immediate centrifugation reveals pink supernatant. All collected specimens have oily appearance. 3+ turbidity is present.

More blood is in tube 1 than tubes 2, 3 or 4. If tube #1 contains blood and subsequent tubes contain diminishing amounts of blood, a traumatic tap has most likely occurred. Blood clots would also indicate a traumatic tap. If the sample is centrifuged within one hour of collection and the supernatant is pink, the color in the CSF is not the result of a traumatic tap, or may not be entirely the result of a traumatic tap. Oily appearance could be due radiographic contrast media. Turbidity could result from a variety of causes. Question Difficulty: Level 9

Tyrosine These are tyrosine crystals, they are usually found in acid/neutral urine and appear as fine needle clumps or rosettes. They are indicative of liver disease. Leucine crystals are associated with liver disease. They are found in acid to neutral pH urine specimens and are yellow in color. Concentric circles and the radial striations are noted microscopically. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. Question Difficulty: Level 4

Name the crystals present on this slide. Leucine Tyrosine Cholesterol Cystine

Bence-Jones proteinuria can be seen in all of the following conditions except: Amyloidosis Nephrotic syndrome Multiple myeloma Macroglobulinemia

Nephrotic syndrome Bence-Jones proteins are monoclonal light chains excreted in the urine, seen with multiple myeloma, and other neoplasms of lymphoid cells. Small amounts can be missed by urine dipsticks, which are more sensitive to albumin than globulins. They are best detected by urine protein electrophoresis, immunoelectrophoresis, or immunofixation. Large amounts cause renal tubular damage, resulting in myeloma kidney. Bence-Jones proteins have unusual heat solubility properties, in that they precipitate between 50- 60 degrees C and redisolve at 90 -100 degrees C. Historical detection methods often utilized this unusual property. Question Difficulty: Level 7

Patterns of hydrolysis of tyrosine, xanthine and casein are characteristics helpful in making species identifications within which genera? Actinomyces Mycobacterium Corynebacterium Nocardia

Nocardia The correct answer is Nocardia. The selective ability to hydrolyze tyrosine, xanthine and casein are characteristics helpful in the species identification of the aerobic actinomycetes, including Nocardia species. These tests have not been used in the identification of any of the other genera of bacteria listed in this question, even though they do have other characteristics in common with Nocardia species. Question Difficulty: Level 7

The following aerobic, branching, filamentous gram-positive species is weakly acid fast and known to cause mycetomas and lung infections in immunocompromised individuals: Nocardia species Mycobacterium species Streptomyces species Corynebacterium species

Nocardia species Nocardia species are branching, gram-positive bacilli that are partially acid-fast organisms due to the presence of mycolic acid in the cell wall. These species cause skin infections such as mycetomas, lymphocutaneous infections, skin abscesses and cellulitis. It may also cause lung and disseminated infections in immunosuppressed patients. Mycobacterium species are strongly acid-fast but do not demonstrate branching as the Nocardia species. Mycobacterium species are noted for causing lung infections. Streptomyces are branching gram-positive, non-acid-fast bacilli that cause mycetomas. Corynebacterium species are most commonly known as skin flora with few species, such as C. diphtheriae, being a significant pathogen. These organisms are non-branching gram-positive, non-acid-fast bacilli. Question Difficulty: Level 7

Which of the following organisms is an acid-fast aerobic actinomycete? Streptomyces spp. Nocardia spp. Actinomadura spp. Nocardiopsis spp.

Nocardia spp. Nocardia spp. are variably acid-fast. Streptomyces spp., Actinomadura spp., and Nocardiopsis spp. are non-acid-fast. Nocardia spp. contain mycolic acid in their cell walls, the other three organisms listed do not have mycolic acid in their cell walls. Question Difficulty: Level 7

Postsplenectomy syndrome The intended response is postsplenectomy syndrome. The scattered atypical RBC's seen in the photograph may be produced in small numbers in normal people; however, the spleen is efficient in removing these from the circulation so that they are not found in a peripheral blood smear of a disease free, untreated patient. However, following splenectomy, scattered acanthocytes, echinocytes, target cells, spherocytes, schistocytes, and Howell-Jolly bodies remain in the circulation. In hemolytic anemia, the significant morphological finding is microspherocytes. In disseminated intravascular coagulation (DIC), the significant morphological findings are schistocytes. In thalassemia minor, the significant morphological findings are target cells. Question Difficulty: Level 5

Note the view of a peripheral blood smear in the photograph. Pictured are scattered acanthocytes, echinocytes, target cells, spherocytes, schistocytes and a Howell-Jolly Body . The condition in which each of these atypical RBC's may be found in the same patient's peripheral blood smear is: Hemolytic anemia Postsplenectomy syndrome Disseminated intravascular coagulation Thalassemia minor

Necator americanus The correct answer is Necator americanus. Necator americanus is one of the hookworms. This species can be identified by observing the rhabditiform larvae that characteristically have a long buccal cavity as illustrated in the photograph. Strongyloides stercoralis rhabditiform larvae have a short buccal cavity. On further examination, a prominent genital primordium may also be observed about one-third the distance from the tail. Enterobius vermicularis does not have an external host and rhabditiform larvae are not formed. Only adult worms and ova are observed in humans. Enterobius can be excluded from this exercise. Ascaris lumbricoides larvae develop into adult worms within the human intestine. The adult worms measure between 15 and 35 cm and may be best recognized by their curved tail. A buccal cavity is not distinctive. Question Difficulty: Level 9

On occasion in cases of heavy infection, rhabditiform nematode larvae, measuring up to 1.5 cm long, may be observed in mounts prepared from stool specimens. A presumptive species identification can be made by microscopically observing the buccal cavity as illustrated in the photograph. What is the most likely species of this nematode? Strongyloides stercoralis Enterobius vermicularis Necator americanus Ascaris lumbricoides

In an electrophoretic separation, if the zones appear artifactually crescent-shaped, what is the MOST likely cause? Insufficient amount of sample Overload of sample Use of phosphate-borate buffer Inadequate fixation prior to staining Voltage setting too high

Overload of sample Sample overload in electrophoresis tends to cause a streak instead of a band. The streaking can look like a crescent-shape. Question Difficulty: Level 7

Which of the following viruses is MOST often reported as the cause of infection leading to aplastic crisis in a patient with sickle cell disease? Adenovirus Epstein-Barr virus Parvovirus B19 Zoster-simplex virus

Parvovirus B19 Parvovirus B19 is the most common causative agent of aplastic crisis in sickle cell disease. An aplastic crisis can accompany or follow a viral, bacterial, or mycoplasmal infection. In this temporary stop to RBC production, in conjunction with the chronic anemia, the anemia worsens. Parvovirus can also halt erythropoiesis in otherwise normal patients (patients without sickle cell anemia), but with a normal RBC lifespan, erythropoiesis is restored before significant changes to RBC concentration happen. Question Difficulty: Level 7

What is the BEST type of microscopy for performing manual platelet counts? Electron Dark-field Light Phase contrast

Phase contrast Phase contrast microscopy can help to better define the outline of the platelets over regular light microscopy, making them easier to count and allowing for more accurate results. Dark-field and electron microscopes are not used for platelet counting. Electron microscopy uses a beam of electrons to create an image of the specimen and is capable of higher magnifications than light microscopy. Dark-field microscopy has the light source blocked causing light to scatter as it hits the specimen. It is used for refractive elements and allows illumination of the specimen against a dark background. Light microscopy is used when performing cellular estimates or differentials with a stained specimen at various magnifications, most commonly 10x, 100x, and 1000x. Question Difficulty: Level 7

Pink, 1 cell thick, No, Yes Pink, 1 cell thick, No, Yes is the correct answer because this image represents a Gram stained smear that is properly prepared and stained. The host cells and background material are stained pink, the cells are evenly distributed (not clumped together), and there is no evidence of precipitated stain. Pink, >1 cell thick, No, Yes is incorrect because the smear does not represent a gram stain that is too thick. Blue, 1 cell thick, No, Yes is incorrect because the smear is pink in color instead of blue. Blue coloring could result in under decolorizing due to a smear being too thick. Blue, >1 cell thick, Yes, No is incorrect because the smear is pink in color, not too thick, no stain precipitate present, and the smear does represent a gram stain appropriate to read. Question Difficulty: Level 4

Pink, 1 cell thick, No, Yes Pink, >1 cell thick, No, Yes Blue, 1 cell thick, No, Yes Blue, >1 cell thick, Yes, No

The cytochrome oxidase-positive bacterial species that is DNAse negative, ornithine decarboxylase positive, and is associated with gastroenteritis in children after the ingestion of contaminated water is most likely: Aeromonas hydrophila Salmonella enterica Plesiomonas shigelloides Shigella sonnei

Plesiomonas shigelloides Pleisiomonas is an oxidase positive organism that is associated with gastrointestinal infections in children. This infection is typically acquired after the ingestion of contaminated water. It is also DNAse and ornithine decarboxylase negative. Aeromonas hydrophila is similar to Pleisiomonas as they are both oxidase positive, associated with contaminated water, and cause gastrointestinal infections in children. However, Aeromonas hydrophilaproduces DNAse and it does not hydrolyze ornithine, two key characteristics by which they are separated from Plesiomonas shigelloides. Salmonella enteritidis is similar to Pleisiomonas as it causes gastrointestinal infections and it is ornithine decarboxylase positive and DNAse negative. The key characteristic that differentiates it from Pleisiomonas is that it is oxidase negative. Shigella sonnei is similar to Pleisiomonas as it can cause gastroenteritis. It is also ornithine decarboxylase positive and DNAse negative; however, it differs from Pleisiomonas as it is cytochrome oxidase negative. Question Difficulty: Level 7

Which of the following is an expected or common laboratory finding in patients with hereditary hemochromatosis (HH)? Elevated hemoglobin and hematocrit Decreased transferrin saturation Presence of HFE mutation Decreased serum ferritin

Presence of HFE mutation Hereditary hemochromatosis (HH) is an inherited condition where there is increased iron absorption in the gut with iron overload over time. Typical laboratory findings in HH include the presence of an HFE mutation. Elevated hemoglobin and hematocrit are not typically associated with patients who have hereditary hemochromatosis. Patients with hereditary hemochromatosis will generally present with an elevated transferrin saturation. Patients with hereditary hemochromatosis will generally present with an elevated serum ferritin. Question Difficulty: Level 7

Plasmodium vivax Plasmodium vivax is the correct response. The affected erythrocyte is distinctively enlarged and the lights pink-staining cytoplasm shows delicate stippling in the form of "Schüffner's dots". The developing trophozoite is enlarged with ameboid extension of its cytoplasm. Plasmodium falciparum is an incorrect response. The infected erythrocytes of P. falciparum are not enlarged and the trophozoites remain in the small circular form and often are plastered on the inner membrane of the infected erythrocytes in an "appliqué" form. Schüffner's dots are not seen. Plasmodium malariae is an incorrected response. The infected erythrocytes are not enlarged and the developing trophozoites extend to the margins of the erythrocyte membrane in the form of a broad "bridge". Schüffner's dots are absent. Plasmodium ovale is an incorrect response. Infected P. ovale erythrocytes of are only slightly enlarged, but are distinctly oval in outline and typically have small ring-like trophozoites. The cytoplasm may show a few aggregates of Schüffner's dot like granules. Question Difficulty: Level 1

Presented in the photomicrograph is a close-in view of an enlarged erythrocyte infested with a malarial trophozoite. Which Plasmodium species is represented with these characteristics? Plasmodium vivax Plasmodium falciparum Plasmodium malariae Plasmodium ovale

A flagellar stain would show peritrichous flagella for each of the following organisms except: Bordetella bronchiseptica Alcaligenes faecalis Pseudomonas aeruginosa Escherichia coli

Pseudomonas aeruginosa The correct answer is Pseudomonas aeruginosa. Pseudomonas aeruginosa, and other Pseudomonas species, are motile via a single polar flagellum. All of the other motile strains listed possess peritrichous flagella. Peritrichous flagella are flagella that occur on all sides of the bacterium. Polar flagella are flagella that extend from one end of the bacterium. Lophotrichous flagella are polar flagella that multiply in tufts at one end or the other. Question Difficulty: Level 8

Which type of electrophoresis is used to separate larger DNA fragments (>50 kb)? Polyacrylamide gel electrophoresis Capillary electrophoresis Isoelectric focusing Pulsed field electrophoresis

Pulsed field electrophoresis Fragments of DNA > 50 kb will not separate in most types of electrophoresis due to limited mobility from their large size. In pulsed field electrophoresis, pulses of electricity are applied in alternating dimensions to better allow for migration. Polyacrylamide gel electrophoresis, or PAGE, is used for small DNA fragments or single-stranded DNA samples. Capillary electrophoresis typically serves as an alternative testing method to high-performance liquid chromatography (HPLC) and is used to separate organic chemicals and inorganic ions. Isoelectric focusing separates proteins based on their isoelectric point, or the pH at which the protein has no charge and does not move. Question Difficulty: Level 7

Within a run, one control is above +2 SD and the other below - 2 SD units from the mean. What do these results indicate? R4S rule is violated due to random error. 22S rule is violated due to random error. R4S rule is violated due to systematic error. 22S rule is violated due to systematic error.

R4S rule is violated due to random error. This is showing that the R4S rule is violated. One control value exceeding +2SD and another exceeding -2SD is how the R4S rule is violated. This allows detection of random error. The 22S rule fail is where two control observations consecutively exceed the same +2S or -2S. This gives high sensitivity to systematic error. Question Difficulty: Level 7

Precision is a measure of: Method accuracy Random variability Method reliability Biological variability

Random variability Precision is the reproducibility of a test demonstrating how close a number of measurements of the same quantity agree with each other. The precision of a test can be reduced by the random errors present in the set of values. Random error is caused by unpredictable changes in the readings of a laboratory instrument, or in the laboratorian's interpretation of the result. There are many other causes of random error also, including interference of the environment with the measurement process. Overall, the higher the precision of a laboratory instrument, the smaller the variability of the small changes in its readings (random errors). Question Difficulty: Level 9

Ideally, a molecular section will have designated and separated areas for which of the following groups of activities? (Choose all that apply.) Specimen login, specimen extraction and reagent preparation, detection and identification Reagent preparation, sample preparation and extraction, amplification and detection/identification Specimen login and reagent preparation, specimen preparation and extraction, amplification and detection/identification Specimen login, reagent preparation, specimen prep and amplification, detection and identification

Reagent preparation, sample preparation and extraction, amplification and detection/identification Specimen login, reagent preparation, specimen prep and amplification, detection and identification The ideal molecular space will provide a "clean" area for the preparation of master mixes and reagents, in the absence of any clinical material. The next separated area would be dedicated to specimen preparation and extraction, and would be removed from the area where amplification occurs, in order to prevent contamination of samples with amplicons from previously processed samples. A third area would be dedicated for amplification, detection and identification. The second and fourth choices provide the desired separation of functions to prevent contamination. The first choice is not correct because it places specimen extraction and reagent prep in the same area. The third choice is not correct because it places specimens during the login process, in the same area where reagents are prepared, which introduces an avenue for reagent contamination. Question Difficulty: Level 9

Paragonimus westermani egg The correct answer is Paragonimus westermani egg. Paragonimus westermani is a fluke egg known to be found in human sputum. The characteristic size, shape and the presence of an obvious operculum aid in its identification. Schistosoma mansoni eggs possess a large lateral spine, Hymenolepsis nana eggs contain a six-hooked oncosphere within a rigid membrane with two polar thickenings, and Diphyllobothrium latum eggs possess an operculum, are smaller than Paragoniumus westermani but are typically found in the intestines. Question Difficulty: Level 5

Recovered from a sputum sample, this suspicious form measures 112 µm by 55 µm. What is the organism? Schistosoma mansoni egg Paragonimus westermani egg Hymenolepsis nana egg Diphyllobothrium latum egg

A A shift is characterized by six consecutive points lying on the same side of the mean. This occurs from day 15 to day 20. Shifts are caused by a change in the assay conditions that affect the accuracy of all results, such as a change in the concentration of the calibrator; change in reagent; a new lot of reagent that differs in composition; or improper temperature setting, wavelength, or sample volume. The term kurtosis refers to the degree of flatness or sharpness in the peak of a set of values having a Gaussian distribution. Harr, Robert R. Medical Laboratory Science Review (Page 230). F.A. Davis Company. Kindle Edition.

Referring to the Levy-Jennings chart, what analytical error is present during the second half of the month? A. Shift B. Trend C. Random error D. Kurtosis

A ficin (enzyme) treated panel can be a useful tool for determining the identity of an antibody. On a ficin-treated panel, reactions with which system would be enhanced? Rh Duffy MNS Kell

Rh Ficin treatment alters the surface of red blood cells such that interactions with Rh, Lewis, and Kidd system antibodies are enhanced. Reactions with MNS (s is variably affected) and Duffy system (Fya and Fyb) antibodies are destroyed. Reactions with Kell system antibodies are unaffected. Question Difficulty: Level 9

On MacConkey (MAC) agar, an isolate from a stool sample produced clear, colorless colonies. On Hektoen enteric (HE) agar, colonies were green with black centers, indicative of H2S production. Additional biochemical tests were positive for methyl red, and negative for indole, VP, citrate, and PAD. From the choices listed, which species best matches the characteristics described? Salmonella Typhi Proteus mirabilis Shigella sonnei Escherichia coli

Salmonella Typhi Salmonella Typhi is the correct response, matching the colony type and biochemical tests listed. In addition to Salmonella Typhi, Proteus mirabilis will produce green colonies with black centers on HE, but Salmonella Typhi may be separated from Proteus mirabilis by its negative PAD. Proteus mirabilis is also a non-fermenter producing green colonies with black centers on HE. In most cases, it is negative for indole, and positive for methyl red and PAD. On HE agar, Shigella sonnei produces green colonies without black centers (negative for H2S). It is a delayed fermenter on MAC (after 48 hours), and is negative for indole, VP, citrate, and PAD. Escherichia coli does not produce H2S, and usually appears as a lactose-fermenter on MAC (pink colonies). It is positive for indole and methyl red, and negative for VP and citrate. Question Difficulty: Level 8

B Basophils contain histamine and heparin in their granules that are released during immediate hypersensitivity/type I hypersensitivity reactions causing inflammation. (Frame B). Frame A contains an eosinophil. Eosinophils are mediators of basophil responses and are increased in parasitic infection. The granules do not contain histamine and heparin. Frame 3 contains a neutrophil with abnormal, aggregated lysosomes that are characteristic to the inherited condition Chediak-Higashi. The granules do not contain histamine and heparin. Frame 4 contains a monocyte that has phagocytized bacteria. Question Difficulty: Level 6

Select the letter representing the cell that contains histamine and heparin responsible for immediate hypersensitivity reactions. A B C D

You are evaluating the effectiveness of a new, office-based rapid test for Influenza B. Among 1000 patients tested for Influenza B, 20 tested positive using this rapid test whereas the remaining 980 patients tested negative. In addition to the 20 patients who tested positive, 10 more patients were infected with influenza B, but tested negative when using this particular rapid test. What is the sensitivity and specificity of this test? Sensitivity = 66% and Specificity = 100% Sensitivity = 100% and Specificity = 75% Sensitivity = 66% and Specificity = 75% Sensitivity = 75% and Specificity = 2%

Sensitivity = 66% and Specificity = 100% To approach this question, we need to know the values for True Positive, True Negative, False Positive, and False Negative. There were 20 true positive patients for Influenza B (number of individuals having the disease correctly identified by the test) and 970 patients were true negative (number of individuals without the disease correctly identified by the test as native). There were 0 false positive patients (number of nondiseased individuals incorrectly identified by the test as positive) and 10 false negative patients (number of diseased individuals incorrectly identified by the test as negative). To calculate for sensitivity and specificity, please refer to the following: Sensitivity = True Positives/(True Positives + False Negatives) Sensitivity = 20/(20 + 10) = 66% Specificity = True Negatives/(True Negatives + False Positives) Specificity = 970/(970 + 0) = 100% Question Difficulty: Level 9

Howell-Jolly bodies Howell-Jolly bodies are composed of DNA and appear as small round ball-like inclusions inside the red cells. Usually only one Howell-Jolly body will be present in each red cell. However, cells may rarely present with more than one Howell-Jolly body. Heinz bodies are composed of denatured hemoglobin. They are visualized with a supravital stain such as new methylene blue. Heinz bodies may appear singly or in multiples within the erythrocyte. Basophilic stippling presents with numerous fine to course blue/purple granules within erythrocytes. These granules are typically evenly distributed throughout the erythrocyte. Basophilic stippling is composed of RNA. Cabot rings are rarely seen in erythrocytes. They are remnants of the mitotic spindle. They appear as fine dark blue/purple granules in a loop or figure eight. Question Difficulty: Level 2

Single erythrocyte inclusions which are large, round, smooth, and purplish-blue staining are most likely: Howell-Jolly bodies Heinz bodies Basophilic stippling Cabot rings

What does the equation in parenthesis measure? (TN/TN+FP) Specificity Sensitivity Precision Variance

Specificity The correct answer is specificity. It is important to differentiate specificity from sensitivity. The specificity of a test is defined as the proportion of cases with absence of the specific disease or condition that gives a negative test result. Specificity = [True Negatives/(True Negatives + False Positives)] x 100 The sensitivity of a test is defined as the proportion of cases with a specific disease or condition that give a positive test result. Sensitivity = [True Positives/(True Positives + False Negatives)] x 100 Precision describes how close the test results are to one another when repeated analyses of the same material are performed. Precision refers to the reproducibility of test results. Variance is the fluctuations in the measurement of a substance away from the desired norm. Question Difficulty: Level 9

In which of the following conditions would one see Pappenheimer bodies on the peripheral blood smear? Iron deficiency anemia Malarial infections G6PD deficiency Splenectomies

Splenectomies Pappenheimer bodies can be found in patients who have had a splenectomy since the spleen typically removes these cells from the peripheral blood. Therefore, if the spleen is no longer present, these RBC's with Pappenheimer bodies can be found in peripheral smears. Iron Deficiency anemia could produce a normocytic, normochromic blood picture until the iron stores are depleted. Then a microcytic, hypochromic would be present. Malaria parasites can appear as ring forms with one or two chromatin dots or as gametes or merozoites inside red blood cells. Heinz bodies would be seen in patients with G6PD deficiency. Question Difficulty: Level 7

Which of the following species are gram positive: Streptococcus Neisseria Listeria Lactobacillus

Streptococcus Listeria Lactobacillus Streptococcus, Listeria, and Lactobacillus are examples of gram-positive organisms. Question Difficulty: Level 7

A 6-year-old girl was seen in the emergency department with pain and tenderness in her lower right quadrant. A CBC showed a high white blood cell count with increased segmented neutrophils and bands. The child was admitted to surgery with a diagnosis of appendicitis. During surgery the appendix appeared normal, but an enlarged node was removed and cultured. A diagnosis of mesenteric lymphadenitis was made. Gram-negative rods were isolated. Which of the following biochemical results are most likely produced by the suspect organism? Triple sugar iron agar (TSIA) acid over acid, H2S negative, lysine positive, indole positive, urea negative TSIA acid over acid, H2S negative, lysine negative, indole variable, urea positive TSIA alkaline over acid, H2S positive, lysine negative, indole negative, urea variable TSIA acid over acid, H2S positive, lysine positive, indole variable, urea negative

TSIA acid over acid, H2S negative, lysine negative, indole variable, urea positive The correct answer is TSIA acid over acid, H2S negative, lysine negative, indole variable, urea positive. This case is typical of Yersinia enterocolitica and the biochemical reactions listed are consistent for this organism.Y. enterocolitica generally presents as severe lower abdominal pain mimicking appendicitis, but infects the mesenteric lymph nodes and may infect the appendix and ileum. TSIA acid over acid, H2S negative, lysine positive, indole positive, urea negative is typical of Escherichia coli. TSIA alkaline over acid, H2S positive, lysine negative, indole negative, urea variable, as well as TSIA acid over acid, H2S positive, lysine positive, indole variable, urea negative are both H2S positive, which is not descriptive of Y. enterocolitica. Question Difficulty: Level 7

Presumptive malignant cells The cells indicated by the arrows in Image A are presumptive malignant cells. Note the large size of the cells, the high nuclear:cytoplasm ratio, vacuolation, and nuclear irregularities. Question Difficulty: Level 1

The arrows in the images below indicate cells that may be observed in CSF samples. Match each image to the cell's identification. Choroidal cells Monomacrophages Presumptive malignant cells Lymphocytes

Rouleaux formation In rouleaux, red blood cells appear as stacked coins. This formation occurs as the result of elevated globulins or fibrinogen in conditions such as inflammatory disorders, multiple myeloma, and lymphoma. Over-drying a blood smear, cold agglutinins (commonly causes clumping of RBCs), and sickle cell anemia (commonly see drepanocytes) are not common reasons for rouleaux formation. Question Difficulty: Level 1

The RBCs indicated by the arrows in this image are the result of: Over drying the blood smear Rouleaux formation Cold agglutinins Sickle cell anemia

Lecithinase production From the Bacillus species commonly encountered in clinical laboratories, only B. cereus, B. anthracis, and B. mycoides produce lecithinase; therefore, this is not a distinguishing characteristic between these three species and thus is the correct answer by exclusion in this exercise. Bacillus cereus is motile, hydrolyzes gelatin, and produces acid fermentatively from salicin. Bacillus anthracis is negative for each of these, which therefore become important differentiating characteristics between these two species. Question Difficulty: Level 7

The beta hemolysis seen around the opaque, flat, spreading colonies illustrated in this photograph of a 5% blood agar plate is helpful in differentiating Bacillus cereus (hemolytic) from Bacillus anthracis (not hemolytic). Each of the following characteristics is also helpful in differentiating these two species EXCEPT: Motility Hydrolysis of gelatin Lecithinase production Fermentation of salicin

White blood cells (WBCs) The cells are white blood cells (WBCs). They have a rough appearance and contain granules and multilobed nuclei which fill out the cytoplasm of the cell. Red blood cells (RBCs) are slightly smaller than WBCs and have a smooth, non-nucleated appearance. Yeast cells appear sometimes similar to RBCs, but they are oval instead of round. They usually appear as budding yeast and in severe infections they can be in the branched mycelial forms. Squamous epithelial cells are the largest cells found in the urine sediment and can even be seen under low-power field. They may appear as clumps of cells and have a very large irregular-shaped cytoplasm with a prominent centrally located nucleus. Question Difficulty: Level 2

The cells that are indicated by the arrows in this urine sediment (using phase contrast microscopy) are: Red blood cells (RBCs) White blood cells (WBCs) Yeast cells Squamous epithelial cells

Cholesterol crystals These are cholesterol crystals. Cholesterol crystals appear in acid urine as large, flat, transparent plates with notched corners. They are soluble in hot alcohol and ether. Leucine crystals are associated with liver disease. They are found in acid to neutral pH urine specimens and are yellow in color. Concentric circles and the radial striations are noted microscopically. Bilirubin crystals are gold-orange, needle-like crystals that may appear in clumps. They are found in acid urine and are associated with liver disease. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. Question Difficulty: Level 2

The crystals seen in this image are ____? Leucine crystals Cholesterol crystals Bilirubin crystals Cystine crystals

Phialophora verrucosum The correct answer is Phialophora verrucosum. Phialophora verrucosum, one of the agents of chromomycosis grows slowly, producing colonies no more than 1 cm in diameter after 7 days incubation. All of the other fungi listed grow rapidly, forming mature colonies within 5-7 days of incubation. The dematiaceous molds can be broadly separated into two major groups: those that take 7 or more days of incubation to mature (slow growers) and those that take only 5-7 days of incubation to mature (rapid growers). These are all possible causes of phaeohyphomycosis (mycotic infections caused by dematiaceous fungi). Question Difficulty: Level 6

The dematiaceous colony illustrated here grew to a diameter of 3 - 4 cm in 5 days. Which of the following fungi can be ruled out based on the information given? Phialophora verrucosum Exserohilum species Alternaria species Ulocladium species

Nocardia asteroides Nocardia asteroides is the correct response. The relatively rapid growth of indented gray-yellow colonies on chocolate agar in five days are suggestive of Nocardia species. The delicate, long, branching bacilli seen microscopically that are acid-fast are also supportive of a presumptive identification. The negative reactions for casein, tyrosine, and xanthine hydrolysis on casein agar provide for a more definitive identification. Most infections occur in immunocompromised hosts or patients on long term cortisone therapy. Respiratory infections are most common. Nocardia brasiliensis colonies are also dry and chalky in consistency, heaped or folded, but distinctive for a deep yellow-orange pigmentation. The gram stain morphology of branching bacilli is similar to those of N. asteroides, although individual cells may be wider. Distinctive is the hydrolysis of casein and tyrosine. Infections are primarily subcutaneous, endemic in many rural regions in South America where field laborers work barefoot in bacterial contaminated soil. Mycobacterium fortuitum colonies grow relatively rapidly within three to four days, are smooth with a waxy consistency, and are gray-white without yellow pigmentation. The bacterial cells in acid-fast preparations are acid fast and consist of a mixture of short, thick rods and filamentous forms. M. fortuitum is reactive for most biochemical tests used for the identification of Mycobacterium species. Casein agar tests are not performed. Mycobacterium fortuitum is ubiquitous as soil and water organisms that contaminate potable water supplies, including various reagents and wash solutions used in homes and hospitals. Streptomyces species colonies growing on Middlebrook agar are relatively small, smooth, entire and gray-white. In acid fast stains, long, slender branching bacilli are observed but are distinctively acid-fast negative. Casein, tyrosine, and xanthine hydrolysis reactions are positive. Most isolates have been recovered from sputum or other respiratory specimens, and from samples obtained from superficial skin wounds. Question Difficulty: Level 1

The dry, chalky, indented, gray-yellow colonies growing in five days on chocolate agar as illustrated in the upper image were recovered from an expectorated sputum sample of a patient with bronchopneumonia. Illustrated in the lower image are delicate, branching, acid-fast bacilli. Key to the identification is negative hydrolysis of casein, tyrosine, and xanthine on casein agar. With these observations, what is the genus/species identification of this isolate? Nocardia asteroides Nocardia brasiliensis Mycobacterium fortuitum Streptomyces species

Necator americanus Necator americanus is the correct response. Characteristic of the genus is the thin, smooth, transparent shell with the developing internal yolk sack retracting from the shell leaving an open clear space. Enterobius vermicularis is an incorrect response. E. vermicularis ova are oval in outline and asymmetrical, with one side flattened and simulating a deflated football. The shell is slightly thickened, smooth, and transparent. A well-developed larva is often observed within the ovum when mature. Trichuris trichiura ova are among those most easy to recognize. They are distinctly barrel-shaped, with characteristic retractile, protruding convex, hyaline polar plugs at either end. The shell is smooth, but relatively thick with an internal developing embryo reaching the inner surface without leaving a space. Ascaris lumbricoides is an incorrect response. Ascaris ova are characteristically yellow-brown (bile-stained), oval or spherical, and have a thick, transparent, hyaline shell, covered by an albuminous coat. Fertilized eggs can be recognized by the cleavage of the internal yolk. A distinct larva may be seen in later stages of development. Question Difficulty: Level 9

The human infections related to the 60 X 40 µm ovum, as illustrated in the image, are reported by the World Health Organization to involve several million people worldwide. Symptoms vary from nausea and diarrhea in patients with light infection, to peripheral edema, anemia, dehydration, and congestive heart failure in those with heavy infections. Select the most likely genus/species identification. Enterobius vermicularis Necator americanus Trichuris trichiura Ascaris lumbricoides

Extensive burns Atypical, fragmented, and triangular erythrocytes devoid of central pallor (schistocytes) are found in conditions of erythrocytic membrane damage. These changes follow as red blood cells are forced through a dense fibrin mesh of clot formation. Severe burns, disseminated intravascular coagulation (DIC), and thrombotic thrombocytopenic purpura (TTP) are all associated with fragmented red cells. In Babesiosis, intracellular forms of the parasite may be seen, but not schistocytes. In Sickle cell disease, affected red cells assume sickled or curved morphology. In von Willebrand's disease, no red cell morphological anomaly is observed. Question Difficulty: Level 6

The presence of erythrocytes with altered morphology as indicated by the arrows in the image has a close association with which of the following conditions? Extensive burns Babesiosis Sickle cell disease Type I von Willebrand's disease

25°C It is common practice in clinical laboratories to incubate the SIM motility tube at room temperature (25°C) when confirming the identification of an unknown species as Listeria monocytogenes. Although motility will be observed at 30°C, this is not the optimum temperature to demonstrate this property. The flagella are inactive at temperatures above 30°C and therefore motility will not be detected at the normal incubator temperatures of 35°C or 37°C or higher (such as 42°C ). Question Difficulty: Level 6

The subsurface umbrella-shaped zone of motility seen in this SIM tube (arrow) is characteristic of Listeria monocytogenes. The optimum temperature of incubation to best illustrate this property is: 25°C 30°C 35°C 42°C

Many gram-positive cocci in pairs, many polymorphonuclear white blood cells (PMNs) The smear is most accurately reported as "Many gram-positive cocci in pairs, many PMNs." It is important to quantitate and describe the morphology (bacilli, cocci, etc.) of the microorganisms that are observed as thoroughly as possible. Include the arrangement of the cells (pairs, clusters, etc.) and report the presence and quantity of host cells (PMNs, epithelial cells, etc.) that are observed on the smear. Question Difficulty: Level 3

This Gram stain was prepared from a lower respiratory tract specimen. How should this Gram stain be reported? Gram-negative cocci Gram-positive cocci Many gram-positive cocci in pairs Many gram-positive cocci in pairs, many polymorphonuclear white blood cells (PMNs)

Moraxella lacunata Moraxella lacunata is the correct answer because performing Gram stains on a smear prepared from the margin of growth inhibition by a 10 µg/ml penicillin disk in a disk diffusion test is a valuable method for differentiating Moraxella species from Neisseria species. This will help determine if the organism in question is a true cocci or has elongated. The bacterial cells of Moraxella species, under the influence of the sub-optimal concentrations of penicillin at the outer margin of growth inhibition, form the elongated, pleomorphic filaments seen here. The bacterial cells of Neisseria species, under these same conditions, remain spherical. Neisseria gonorrhoeae is incorrect because the Gram stain demonstrates elongated, pleomorphic filaments rather than true cocci. Neisseria sicca is incorrect because the Gram stain demonstrates elongated, pleomorphic filaments rather than true cocci. Acinetobacter baumannii is a true Gram negative rod that can demonstrate a Gram negative coccobacilli morphology. Acinetobacter species can resist decolorization causing them to appear as gram positive instead of gram negative. The organism can also be mistaken for a Neisseria species due to the coccobacilli morphology when staining gram negative. Acinetobacter species are oxidase negative while Neisseria species are oxidase positive. Question Difficulty: Level 6

Tiny translucent gray colonies were recovered on blood agar from a patient with purulent conjunctivitis. Gram negative diplococci were seen on Gram stain. The preparation illustrated in this photomicrograph was obtained from colonies growing at the margin of inhibition of a 10 µg/ml penicillin disk. The most likely identification is: Neisseria gonorrhoeae Moraxella lacunata Neisseria sicca Acinetobacter baumannii

The following organism causes White Piedra which infects hairs on the face, scalp, and body areas: Microsporum canis Trichosporon beigelii Piedraia hortae Microsporum audouiniI

Trichosporon beigelii White piedra, caused by Trichosporon beigelii, is a superficial fungal infection of the hair shaft. Infected hairs grow white/light brown nodules (~1.0 - 1.5 mm) along the shaft. Hair damage usually results as the infection invades the hair cortex. This infection is most commonly found in young adults. Microsporum canis is a dermatophyte that is capable of causing tinea (ringworm) infections of the skin and hair. It is transmitted through contact with dogs and cats with ringworm. Piedraia hortae causes black piedra which is a fungal infection of the hair. It produces a hard nodule that attaches to the shaft of the hair. The Microsporum species are one of the dermatophytes that cause tinea (ringworm) infections of the skin and hair. Microsporum audouiniI is an anthropophilic organism. It is spread directly from contaminated objects like hats and combs. Question Difficulty: Level 8

Which of the following is NOT associated with immediate hypersensitivity? Hay fever Urticaria (Hives) Tuberculin reaction Anaphylactic shock

Tuberculin reaction Hay fever, urticaria, and anaphylactic shock are all associated with immediate hypersensitivity reactions, which generally appears within 30-60 minutes of an antigen challenge. These reactions are due to the binding of IgE antibodies to receptors on mast cells and basophils, triggering them to release vasoactive mediators. The tuberculin skin reaction is a delayed hypersensitivity reaction that is due to the effects of T lymphocytes and cytokines, and appears 48-72 hours after antigen exposure. Question Difficulty: Level 7

Select from the multiple choices the specimen that is inadequate for the recovery of anaerobes and should be summarily rejected upon receipt in the microbiology laboratory. Swab specimens taken from of deep sub-cutaneous abscess Needle aspirate in an anaerobic E-swab tube Syringe aspirate hand-carried to microbiology laboratory Uterine cervical swab in Cary-Blair transport medium

Uterine cervical swab in Cary-Blair transport medium Uterine cervical swab in Cary-Blair transport medium is the correct response. Decisions on the criteria for rejection of specimens sent for culture will be determined within each microbiology laboratory. In general, swab specimens of superficial infections are considered inadequate for the recovery of anaerobes as most species will not survive after exposure to environmental oxygen. Cary-Blair transport medium is specifically formulated to enhance the recovery of enteric bacterial pathogens and anaerobes may not survive. Swab specimens taken from deep subcutaneous abscesses are not excluded for culture as exposure to oxygen has been minimal and anaerobes will be recovered as long as an anaerobic transport tube has been used. Needle aspirates submitted in an anaerobic E-swab tube is the ideal method for collection and transport of specimens for the culture recovery of anaerobic bacteria. Syringe aspirates that are hand carried to the microbiology laboratory immediately after collection are suitable for recovery of anaerobes. Syringes used for aspiration extend deep into the substance of an infection where environmental exposure to oxygen is minimal. The amount of time required to hand carry an aspirated specimen within a syringe to the laboratory does not provide sufficient time to affect the recovery of anaerobes that may be present. Question Difficulty: Level 9

In the preliminary identification of the Enterobacteriaceae, it is helpful to separate the various species into tribes. Which of the following is the biochemical characteristic for which the tribe Klebsielleae can be recognized? Phenylalanine deaminase + + - - IMViC reactions Voges Proskauer Hydrogen sulfide

Voges Proskauer The production of acetyl methyl carbinol, positive Voges Proskauer (VP), is common to all members of the Tribe Klebsielleae. Phenylalanine deaminase activity is linked to the tribe Proteeae. + + - - IMViC reactions are characteristic of the tribe Escherichieae. IMViC stands for indole, methyl red, Voges Proskauer and citrate. Hydrogen sulfide, although not unique, separates the tribe Edwardsielleae, from the Tribe Escherichieae. Question Difficulty: Level 7

None This slide contains normochromic, normocytic red blood cells with no inclusions. Polychromasia would be present when some of the cells appeared slightly larger with a gray to bluish tinge. This indicates the presence of reticulocytes. Howell-Jolly bodies are RBC inclusions and are composed of nuclear (DNA) remnants. They are typically associated with megaloblastic anemias. Basophilic stippling are RBC inclusions that composed of precipitated RNA and mitochondrial remnants. Basophilic stippling is often associated with lead poisoning. Question Difficulty: Level 3

What abnormality is present in this slide? None Polychromasia Howell-Jolly body Basophilic stippling

Burr cells (echinocytes) These are burr cells (echinocytes). Notice that the projections are short, rounded and evenly spaced around the cell surface. Sickle cells (drepanocytes) are thin, dense elongated cells that are pointed at both ends. They are often curved or sickle shaped. Acanthocytes are cells with irregularly spaced projections around the cell surface. The projections vary in length, but often tend to be longer than burr cells. Elliptocytes are abnormally shaped cells demonstrating an elliptical or cigar-shape. There are usually no abnormal projections on the surface of an elliptocyte. Question Difficulty: Level 2

What type of red cells are indicated by the arrows in this image? Sickle cells (drepanocytes) Burr cells (echinocytes) Acanthocytes Elliptocytes

Polychromatophilic RBCs These cells are classified as polychromatophilic RBCs. They have a blue-gray appearance when compared to the other RBCs in the field and are larger in size than mature RBCs. They also have diminished central pallor. While the cells most likely represent reticulocytes they cannot be definitively identified as such from a Wright-stained smear. A supravital stain such as New Methylene Blue must be used for confirmation. The cells are not normal mature RBCs, as they are larger than normal (> 8-9 microns in diameter), have a blue-gray appearance and lack the typical central pallor of a normal mature RBC. Mature RBCs are generally red-orange in color, between 6-8 microns in diameter and have a distinct central pallor that takes up approximately 1/3 of the cell. The stain on this smear and the distribution area is acceptable and therefore, the color and appearance of these cells would not be considered staining artifact. Question Difficulty: Level 1

While performing a peripheral blood smear review, you observe the cells indicated by the arrows on this Wright-Giemsa stained slide. How would you classify these cells? Reticulocytes Normal mature red blood cells (RBCs) Polychromatophilic RBCs Staining artifacts

From the choices listed below, select the characteristic that would immediately rule out a presumptive identification of Mycobacterium tuberculosis: Positive niacin accumulation reaction Acid-fast bacilli arranged in parallel bundles Yellow pigmented colonies after exposure to light Positive reactions for nitrate reduction and urease

Yellow pigmented colonies after exposure to light Yellow pigmented colonies after exposure to light is the correct response. The colonies of Mycobacterium tuberculosis remain rough, buff, and do not develop pigmentation either initially upon recovery in culture, or in particular after exposure to light, or nonchromogenic. Presumptive identifications of Mycobacterium tuberculosis can be made, and not ruled out, by demonstrating the positive yellow color in a niacin reagent tube that is a positive indicator of niacin accumulation, by observing in acid fast stained slide mounts prepared from colonies the red-staining elongated bacilli arranged in parallel bundles, and the positive reactions for nitrate reduction and urease for which M. tuberculosis is positive for both reactions. Question Difficulty: Level 9

The gene loci for the alpha globin chains are adjacent to the locus for which other globin chain? Beta Delta Epsilon Zeta

Zeta The order of globin gene loci on chromosome 16 is Zeta, Alpha 2, and Alpha 1. Beta globin gene, delta globin gene, and epsilon globin genes are found on chromosome 11. Question Difficulty: Level 7

Which genotype is associated with alpha thalassemia minor? -α/αα -α/-α --/-α --/--

-α/-α Deletion of two out of four alpha chain gene loci results in alpha thalassemia minor. The deletions may be homozygous or heterozygous. In the homozygous state (-α/-α), both parents contribute one missing gene locus. In the heterozygous state (--/αα), one parent contributes a normal gene while the other one a gene with both alpha chain gene loci deleted. The genotype -α/αα phenotypically is a silent carrier (normal). The genotype --/-α phenotypes as Hemoglobin H disease (chronic, moderately severe hemolytic anemia). The genotype --/-- phenotypes as hydrops fetalis (fatal). Question Difficulty: Level 8

Which of the following conditions will interfere with the measurement of LD? A. Slight hemolysis during sample collection B. Storage at 4°C for 3 days C. Storage at room temperature for 16 hours D. Use of plasma collected in heparin

A RBCs are rich in LD-1 and LD-2, and even slight hemolysis will falsely elevate results. Hemolytic, megaloblastic, and pernicious anemias are associated with LD levels of 10-50 times the URL. LD is stable for 2 days at room temperature or 1 week at 4°C; however, freezing causes deterioration of LD-5. The activity of LD is inhibited by EDTA, which binds divalent cations; serum or heparinized plasma should be used. Harr, Robert R. Medical Laboratory Science Review (Page 265). F.A. Davis Company. Kindle Edition.

SITUATION: The Ortho Provue reports a type on a woman who is 6 weeks pregnant with vaginal bleeding as O negative. The woman tells the emergency department physician she is O positive and presents a blood donor card. The medical laboratory scientist performs a test for weak D and observes a 1+ reaction in AHG phase. A Kleihauer-Betke test is negative. Is this woman a candidate for RhIg? A. No, she is Rh positive B. Yes, she is a genetic weak D C. No, there is no evidence of a fetal bleed D. Yes, based upon the Provue results

A The negative Kleihauer-Betke test confirms that the positive reaction of the woman's RBCs with anti-D at IAT is not the result of a fetal-maternal bleed. The woman is weak D positive, and, therefore, is not a candidate for RhIg. Typically, a test for weak D is not done as part of the obstetric workup. In such cases, if the rosette test is positive, the mother is given RhIg. Harr, Robert R. Medical Laboratory Science Review (Page 159). F.A. Davis Company. Kindle Edition.

Hemolytic uremic syndrome (HUS) The intended response is hemolytic uremic syndrome(HUS). The presence of polychromatic erythrocytes (blue arrow in the upper photograph) and scattered spherocytes support a hemolytic process. Scattered schistocytes and helmet cells are present in HUS. A platelet count of 85,000/uL (normal range 150,000-450,000/uL) is compatible with thrombotic thrombocytopenic purpura (TTP). Spherocytes would appear as the predominate erythrocytes in a case of hereditary spherocytosis. Hemoglobin is often normal, but infection, fever, and stress can cause the spleen to destroy more red blood cells. If this had occurred, the hemoglobin would be low, but the patient would also appear jaundiced due to an increase in bilirubin. Unlike TTP, HUS is characterized by association with an E.coli O157:H7 infection in roughly 80% of cases. This can lead to renal failure due to destruction of red blood cells. Though there are cell fragments/poikilocytosis in hereditary pyropoikilocytosis. This autosomal recessive trait is usually seen in infancy with an MCV that is most likely to be much lower than 50 (range of 25-55 fL). The fragmentation is due to heat for these patients not from a bacterial infection. Question Difficulty: Level 6

A 3-year-old girl was brought to a physician's office because of fever and bacterial-type illness symptoms. Her blood pressure was elevated. Gram stain of peripheral blood shows Gram-negative rods. Hemogram: hemoglobin 9.1g/dL (normal 12.0 - 16.0 g/dL), hematocrit 28% (normal 37 - 48%), MCV 80 fl (normal 86 - 98 fl), RDW 13.1% (normal 11 - 15%), platelets 85.1 X 109/L (normal 150 - 450 X 109/L) WBC 9.9x109/L (normal 4.3 - 10.8 x 109/L). The peripheral blood smear is represented in the photograph. Which of the following is the most likely associated condition? Hereditary spherocytosis Thrombotic thrombocytopenic purpura (TTP) Hemolytic uremic syndrome (HUS) Hereditary Pyropoikilocytosis (HPP)

An immunosuppressed man has several episodes of pneumonia, intestinal pain, sepsis with gram-negative rods, and a history of military service in Southeast Asia 20 years earlier. The most likely cause is infection with: A. Trypanosoma cruzi B. Strongyloides stercoralis C. Naegleria fowleri D. Paragonimus westermani

B A latent infection with S. stercoralis acquired years before may cause severe symptoms in the immunosuppressed patient ("autoinfective" capability of life cycle and migratory route of the larvae through the body). Harr, Robert R. Medical Laboratory Science Review (Page 470). F.A. Davis Company. Kindle Edition.

In a patient with diarrhea, occasionally Entamoeba histolytica/E. dispar (four nucleated cysts, no chromatoidal bars) are identified as being present; however, these cells, which are misdiagnosed as protozoa, are really: A. Macrophages B. Polymorphonuclear leukocytes C. Epithelial cells D. Eosinophils

B As polymorphonuclear leukocyte (PMN) nuclei in stool begin to fragment and appear to be four nuclei, they will resemble E. histolytica/E. dispar cysts. However, E. histolytica/E. dispar cysts are rarely seen in cases of diarrhea. The species name E. histolytica is reserved for the true pathogen, whereas E. dispar is used for the nonpathogenic species. Unfortunately, morphologically they look identical. The only time E. histolytica could be identified morphologically would be from trophozoites containing ingested red blood cells (RBCs). Nonpathogenic E. dispar would not contain ingested RBCs. The correct way to report these organisms is Entamoeba histolytica/E. dispar (no trophozoites containing ingested RBCs) or Entamoeba histolytica (trophozoites seen that contain ingested RBCs). Physicians may treat based on patient symptoms. Harr, Robert R. Medical Laboratory Science Review (Page 463). F.A. Davis Company. Kindle Edition.

A neonate was readmitted to the hospital with a diagnosis of meningitis. The CSF revealed gram-negative straight rods. At 24 hours, the organism grew on 5% sheep blood and chocolate agars displaying a yellow pigment. On MacConkey agar, it appeared as a non-lactose fermenter. Colonies were oxidase, DNase, and gelatinase positive, and oxidized glucose and mannitol. What is the most likely identification? A. Haemophilus influenza B. Chryseobacterium meningosepticum C. Stenotrophomonas maltophilia D. Acinetobacter baumannii

B Chryseobacterium meningosepticum can cause septicemia and meningitis in neonates and immunocompromised adults. The ability to encapsulate, produce proteases, and survive in chlorinated tap water are factors that contribute to hospital-acquired infections with this bacterium. Harr, Robert R. Medical Laboratory Science Review (Page 414). F.A. Davis Company. Kindle Edition.

The following characteristics of an obligate anaerobic gram-negative bacilli best describe which of the listed genera? Gram stain: long, slender rods with pointed ends Colonial appearance: dry bread crumbs or "fried-egg" appearance Penicillin 2-unit disk test: Susceptible A. Bacteroides spp. B. Fusobacterium spp. C. Prevotella spp. D. Porphyromonas spp.

B Fusobacterium spp. are usually spindle-shaped, slim rods, whereas the other genera are small rods (variable length for Bacteroides spp. and tiny coccoid rods for Prevotella and Porphyromonas spp.). Fusobacterium spp. and Porphyromonas spp. are susceptible to penicillin 2-unit disks, while most Bacteroides spp. and Prevotella spp. are resistant. Harr, Robert R. Medical Laboratory Science Review (Page 437). F.A. Davis Company. Kindle Edition.

A fetal screen yielded negative results on a mother who is O negative and infant who is O positive. What course of action should be taken? A. Perform a Kleihauer-Betke test B. Issue one full dose of RhIg C. Perform a DAT on the infant D. Perform an antibody screen on the mother

B If the fetal screen or rosette test is negative, indicating the fetal maternal blood is negligible in a possible RhIg candidate, standard practice is to issue one dose of RhIg. Harr, Robert R. Medical Laboratory Science Review (Page 158). F.A. Davis Company. Kindle Edition.

SITUATION: A shipment from a laboratory supply company arrived over the weekend. The shipment consisted of glass slides, latex gloves, and plastic test tubes—all nonperishable items. It was left on the outside loading dock overnight. Are these supplies useable for patient care/testing? A. Yes, with no further quality assurance testing required B. Yes, but only after quality analysis is performed to ensure they were not affected adversely C. No, the latex gloves might be contaminated, but the slides and test tubes may be used D. No, all supplies left outside for 24 hours unattended must be discarded

B Laboratories must have written policies for determining whether laboratory reagents and supplies may be used. Nonperishable items should be inspected for contamination, damage, and manufacturing defects. Because items left in an uncontrolled environment may be exposed to adverse conditions such as extreme temperatures, they should be inspected and tested to ensure that their performance is unaffected. Harr, Robert R. Medical Laboratory Science Review (Page 534). F.A. Davis Company. Kindle Edition.

Which mycobacterium of the M. tuberculosis complex fails to grow in culture and has a characteristic "croissant-like" morphology in stained smears? A. M. africanum B. M. microti C. M. bovis D. M. leprae

B M. microti is found in guinea pigs, rabbits, cats, and other warm-blooded animals. It is a cause of tuberculosis in immunocompromised humans, but is also known to cause tuberculosis in immunocompetent persons as well. M. microti cannot be cultured in vitro, but can be distinguished from M. leprae by its distinctive "croissant-like" morphology. Diagnosis is confirmed by NAT. Harr, Robert R. Medical Laboratory Science Review (Page 443). F.A. Davis Company. Kindle Edition.

A bone marrow specimen was obtained from an immunocompromised patient who tested positive for HIV. The organism grew rapidly at 3 days showing a mold form (at 25°C), displaying conidiophores with four to five terminal metulae with each having four to six phialides. The conidia at the end of the phialides were oval and in short chains. They appear as a fan or broom when viewing under 10× and 40×. At 37°C, the yeast form grew more slowly, showing conidia that formed hyphal elements breaking at the septa to produce oval arthroconidia. This thermodimorphic mold is most likely: A. Paecilomyces spp. B. Penicillium marneffei C. Rhizomucor spp. D. Aspergillus fumigatus

B Other Penicillium spp. are differentiated from P. marneffei (thermally dimorphic) through conversion from the mold to yeast phase. P. marneffei are seen as yeast at 35°C-37°C on 5% sheep blood agar or in BHI broth. Other Penicillium spp. do not display a yeast phase. P. marneffei are recovered from blood, skin, lymph nodes, bone marrow, and internal organs of immunocompromised patients. Harr, Robert R. Medical Laboratory Science Review (Page 454). F.A. Davis Company. Kindle Edition.

A 15-year-old female complained of a severe eye irritation after removing her soft-contact lenses. A swab of the infected right eye was obtained by an ophthalmologist, who ordered a culture and sensitivity test. The culture was plated on blood agar and MacConkey agar. At 24 hours, growth of a gram-negative rod that tested positive for cytochrome oxidase was noted. The Mueller-Hinton sensitivity plate showed a bluish-green "lawn" of growth that proved highly resistant to most of the antibiotics tested except amikacin, tobramycin, and ciprofloxacin. What is the most likely identification? A. Burkholderia cepacia B. Pseudomonas aeruginosa C. Stenotrophomonas maltophilia D. Acinetobacter baumannii

B P. aeruginosa is an opportunistic organism that is not part of the human normal flora. Contact lens solution contamination, eye injury, or contact lens eye trauma are factors that contribute to P. aeruginosa eye infections. The characteristic blue-green pigment on Mueller-Hinton agar (pyocyanin pigment) produced by P. aeruginosa and the high resistance to antibiotics aid in its identification. Harr, Robert R. Medical Laboratory Science Review (Page 404). F.A. Davis Company. Kindle Edition.

Smooth gray colonies showing no hemolysis are recovered from an infected cat scratch on blood and chocolate agar but fail to grow on MacConkey agar. The organisms are gram-negative pleomorphic rods that are both catalase and oxidase positive and strongly indole positive. The most likely organism is: A. Capnocytophaga spp. B. Pasteurella spp. C. Proteus spp. D. Pseudomonas spp.

B Pasteurella multocida (P. canis) is part of the normal mouth flora of cats and dogs and is frequently recovered from wounds inflicted by them. It produces large amounts of indole and therefore an odor resembling colonies of E. coli. Pseudomonas spp. are also catalase and oxidase positive but can be ruled out because they grow on MacConkey agar and do not produce indole. Harr, Robert R. Medical Laboratory Science Review (Page 409). F.A. Davis Company. Kindle Edition.

What is the component of choice for a patient with chronic granulomatous disease (CGD)? A. FFP B. Granulocytes C. Cryoprecipitate D. RBCs

B Patients with CGD cannot fight bacterial infections due to dysfunctional phagocytic enzymes; granulocyte concentrates are the product of choice for these patients. Harr, Robert R. Medical Laboratory Science Review (Page 150). F.A. Davis Company. Kindle Edition.

Anti-E is detected in the serum of a woman in the first trimester of pregnancy. The first titer for anti-E is 32. Two weeks leater, the antibody titer is 64 and then 128 after another 2 weeks. Clinically, there are beginning signs of fetal distress. What may be done? A Induce labor for early delivery B. Perform plasmapheresis to remove anti-E from the mother C. Administer RhIg to the mother D. Perform an intrauterine transfusion using E-negative cells

B Plasmapheresis removes excess anti-E from the mother and provides a temporary solution to the problem until the fetus is mature enough to be delivered. The procedure may need to be performed several times, depending upon how quickly and how high the levels of anti-E rise. Administration of RhIg would not contribute to solving this problem caused by anti-E. Intrauterine transfusion would not be performed before week 20, and would be considered only if there is evidence of severe hemolytic disease. Harr, Robert R. Medical Laboratory Science Review (Page 160). F.A. Davis Company. Kindle Edition.

Fecal immunoassays have become more commonly used to diagnose infections with: A. Endolimax nana and Blastocystis hominis B. Giardia lamblia and Cryptosporidium spp. C. Ascaris lumbricoides and Trichuris trichiura D. Strongyloides stercoralis and Trichomonas vaginalis

B Rapid fecal immunoassays have become more widely used for the diagnosis of infections with G. lamblia and Cryptosporidium. For these two organisms, the fecal immunoassays are more sensitive than the routine O&P examination. Harr, Robert R. Medical Laboratory Science Review (Page 468). F.A. Davis Company. Kindle Edition.

A germ tube-negative, pink yeast isolate was recovered from the respiratory secretions and urine of a patient with AIDS. Given the following results, what is the most likely identification? CORNMEAL TWEEN 80 AGAR Blastoconidia = + Pseudohyphae = Neg Arthroconidia= Neg Urease = + A. Candida albicans B. Rhodotorula spp. C. Cryptococcus spp. D. Trichosporon spp.

B Rhodotorula spp. produce pink- to coral-colored colonies on Sabouraud's agar and cornmeal agar. It is usually considered a contaminant but is an opportunistic pathogen, and must be identified when found in specimens from immunosuppressed patients. Harr, Robert R. Medical Laboratory Science Review (Page 448). F.A. Davis Company. Kindle Edition.

How can a false-negative PCR test caused by the presence of an inhibitor of the reaction in a patient's sample be detected? A. Using a positive control B. Using an internal control C. Performing each test in duplicate D. Performing serial dilutions of the sample

B Some samples may contain inhibitors of the PCR reaction. For example, a sample in which DNA was extracted using a cation chelator to prevent DNA degradation may be contaminated with residual chelating reagent. Since DNA polymerase requires Mg +2, this will inhibit amplicon production. An internal control can identify this problem. The sample is mixed with the internal control, a DNA molecule with the same primer binding region. The internal control should always be amplified, but the product can be distinguished from the target amplicons. Failure of a sample to demonstrate the internal control product in an assay where positive and negative control reactions are valid indicates the presence of an inhibitor in the sample. Harr, Robert R. Medical Laboratory Science Review (Page 504). F.A. Davis Company. Kindle Edition.

When preparing a patient for an oral glucose tolerance test (OGTT), which of the following conditions will lead to erroneous results? A. The patient remains ambulatory for 3 days prior to the test B. Carbohydrate intake is restricted to below 150 g/day for 3 days prior to test C. No food, coffee, tea, or smoking is allowed 8 hours before and during the test D. Administration of 75 g of glucose is given to an adult patient following a 10-12-hour fast

B Standardized OGTTs require that patients receive at least 150 grams of carbohydrate per day for 3 days prior to the test in order to stabilize the synthesis of inducible glycolytic enzymes. The 2-hour OGTT test is no longer recommended for screening and should be reserved for confirmation of diabetes in cases that are difficult to diagnose, such as persons who lack symptoms and signs of fasting hyperglycemia. Harr, Robert R. Medical Laboratory Science Review (Page 206). F.A. Davis Company. Kindle Edition.

In which condition is the measurement of acid phosphatase clinically useful? A. Measuring the prostatic isoenzyme to screen for prostate cancer B. Measuring the enzyme in a vaginal swab extract C. The diagnosis of hemolytic anemia D. As a marker for bone regeneration

B The PSA test is clinically more sensitive than prostatic acid phosphatase in detecting prostatic cancer. The clinical use of prostatic acid phosphatase is confined to the investigation of sexual assault. Acid phosphatase activity > 50 IU/L establishes the presence of seminal fluid in the vaginal sample. Tartrate-resistant acid phosphatase is used as a cytochemical marker for hairy-cell leukemia, and may be measured in serum to identify diseases with increased osteoclast activity, particularly malignancies involving bone. Harr, Robert R. Medical Laboratory Science Review (Page 277). F.A. Davis Company. Kindle Edition.

In a condition resulting from the accidental ingestion of eggs, the human becomes the intermediate rather than the definitive host. The correct answer is: A. Trichinosis B. Cysticercosis C. Ascariasis D. Strongyloidiasis

B The accidental ingestion of T. solium eggs can result in the disease called cysticercosis. The cysticerci will develop in a number of different tissues, including the brain, and the human is the accidental intermediate host. Harr, Robert R. Medical Laboratory Science Review (Page 471). F.A. Davis Company. Kindle Edition.

A transplant patient on immunosuppressive drugs developed increasing diarrhea. The most likely combination of disease and diagnostic procedure is: A. Trichinosis and trichrome stain B. Microsporidiosis and modified trichrome stain C. Toxoplasmosis and Gram stain D. Paragonimiasis and wet preparation

B The fact that the patient has received a transplant, is on immunosuppressive drugs, and has continuing diarrhea suggests microsporidiosis; the appropriate diagnostic test would be modified trichrome staining of fecal material. Harr, Robert R. Medical Laboratory Science Review (Page 472). F.A. Davis Company. Kindle Edition.

Why do Rh-negative women tend to have a positive antibody screen compared to Rh-positive women of childbearing age? A. They have formed active anti-D B. They have received RhIg C. They have formed anti-K D. They have a higher rate of transfusion

B The most common reason an Rh-negative woman has a positive antibody screen is because of previously receiving RhIg or passive anti-D. Harr, Robert R. Medical Laboratory Science Review (Page 161). F.A. Davis Company. Kindle Edition.

A gram-negative S-shaped rod recovered from selective media for Campylobacter species gave the following results: Catalase = + Oxidase = + Motility = + Hippurate hydrolysis = + Growth at 42°C = + Nalidixic acid = Susceptible Pigment = Neg Grape odor = Neg Cephalothin = Resistant The most likely identification is: A. Pseudomonas aeruginosa B. Campylobacter jejuni C. Campylobacter fetus D. Pseudomonas putida

B The only Campylobacter spp. that hydrolyze hippurate are C. jejuni and subsp. doylei. However, some strains of P. aeruginosa grow on agar selective for Campylobacter at 42°C. C. fetus will not grow at 42°C but will grow at 25°C and 37°C. Harr, Robert R. Medical Laboratory Science Review (Page 406). F.A. Davis Company. Kindle Edition.

SITUATION: John Smith donated a unit of whole blood in May. Red blood cells made from the whole blood were transfused to a recipient of a community hospital in June with no apparent complications. The blood supplier notified the medical director of the hospital that the donor reported high-risk behavior with another male in April, although viral tests remain negative and the donor is healthy. What course of action should be taken? A. No action should be taken B. The recipient's physician should be notified C. The recipient's physician and the recipient should be notified D. The recipient should be notified

B The recipient's physician should be notified by the medical director to ascertain the current health status of the recipient, if known, and determine what treatment, if any, the recipient should receive. Harr, Robert R. Medical Laboratory Science Review (Page 163). F.A. Davis Company. Kindle Edition.

A 76-year-old female diagnosed with urosepsis was transfused 2 units of packed red blood cells. Her type was AB positive with a negative antibody screen. The units transfused were AB positive. Upon receiving the second unit, the patient became hypoxic with tachypnea. The clerical cehck was acceptable and DAT negative. She received 269 mL from the second unit before a reaction was called. Her temperature fell from 38 degrees Celsius to 36.4, her pulse increased from 72 to 90, and respiration rose from 35 to 41. Her BP was 110/70. The patient expired approximately 12 hours from the time the reaction was called. What type of reaction was most likely present? A. Febrile B. Symptoms not related to transfusion C. Allergic D. TRALI

B This case emphasizes the statistic that not all causes of death are related to transfusion. The temperature dropped ruling out a febrile reaction; there was no evidence of pulmonary edema or hypotension seen with TRALI (and plasma products are more associated with TRALI than red cells); and there was no sign of hives or itching, which are often associated with an allergic reaction. Harr, Robert R. Medical Laboratory Science Review (Page 147). F.A. Davis Company. Kindle Edition.

SITUATION: A urine sample with a pH of 6.0 produces an abundance of pink sediment after centrifugation that appears as densely packed yellow- to reddish-brown granules under the microscope. The crystals are so dense that no other formed elements can be evaluated. What is the best course of action? A. Request a new urine specimen B. Suspend the sediment in prewarmed saline, then repeat centrifugation C. Acidify a 12-mL aliquot with three drops of glacial acetic acid and heat to 56°C for 5 minutes before centrifuging D. Add five drops of 1N HCl to the sediment and examine

B Urates are yellow- or reddish-brown granules and form in acid or neutral urine. They often form following refrigeration of urine and can be dissolved by addition of warm saline or dilute NaOH. Amorphous phosphates are colorless and form in neutral or alkaline urine. They dissolve in dilute acetic acid but precipitate if heated. Harr, Robert R. Medical Laboratory Science Review (Page 346). F.A. Davis Company. Kindle Edition.

SITUATION: A patient tested positive for HIV-1 infection using a reverse transcriptase-polymerase chain reaction (RT-PCR) method. However, 1 week later a second blood sample was collected and sent to a reference lab that performed a confirmatory test by Western blot. The Western blot test was negative. What best explains these results? A. The samples for RT-PCR and Western blot were not from the same patient B. RT-PCR is more sensitive for early detection C. The RT-PCR result was falsely positive D. The RT-PCR test detected HIV-2 and the Western blot is specific for HIV-1

B Western blot is a test for antibodies to HIV, and sufficient antibodies are not usually present in the first 3-4 weeks of infection to cause a positive test. In some persons, antibodies do not appear until 3 months after initial HIV infection. RT-PCR detects viral RNA, and reduces the window phase of infection to approximately 1 week. Real-time PCR tests for HIV-1 have 100% specificity at a cutoff of 20-40 copies RNA/mL. PCR is the preferred test for neonates because it avoids detection of maternal antibody, and is replacing Western blot as the confirmatory test of choice. Harr, Robert R. Medical Laboratory Science Review (Page 462). F.A. Davis Company. Kindle Edition.

Which of the following statements concerning vancomycin resistance in Enterococci is TRUE? Van A and Van C are the most clinically significant phenotypes. Van B confers intrinsic low level resistance to vancomycin only. High level vancomycin resistance is characteristic of E. gallinarum and E. casseliflavus. Both ampicillin and vancomycin resistance are found more frequently in E. faecium than in E. faecalis.

Both ampicillin and vancomycin resistance are found more frequently in E. faecium than in E. faecalis. The correct answer is both ampicillin and vancomycin resistance are found more frequently in E. faecium than in E. faecalis. Van C confers low level intrinsic resistance to vancomycin and is characteristic in E. gallinarum and E. caseliflavus. Of the six described phenotypes of glycopeptide resistance in enterococci, Van A and Van B are the most clinically significant. Van A confers high level resistance to both vancomycin and teicoplanin; Van B confers moderate to high resistance to vancomycin only. Low level vancomycin resistance is characteristic of E. gallinarum and E. casseliflavus, not high. Question Difficulty: Level 7

What organism produced outside a bioterrorism event causes glanders disease? Burkholderia mallei Francisella tularensis Yersinia pestis Variola virus

Burkholderia mallei Burkholderia mallei is the causative agent for Glanders which primarily affects animals such as donkeys, mules, and horses. Human infection is rare and usually occurs in people working with infected animals or laboratory workers handling the organism. Glanders is a respiratory illness that forms nodular lesions in the lung tissue and can cause ulcers leading to sepsis and death. Francisella tularensis is the causative agent of tularemia. Humans are most commonly infected from the bite of an infected tick or fly. Other means of infection include direct contact with the blood of infected animals when skinning game, eating contaminated meat, drinking contaminated water, or inhaling the organisms produced by aerosols. The WHO estimates that 50 kg of the organism could infect 125,000 people and cause up to 19,000 deaths. Yersinia pestis is found primarily in rodents, but can also be found in several other animal species. Human-to-human transmission occurs by either flea bite or respiratory droplets. This causes an overwhelming disease known as pneumonic plague, or Black Death, which is the most likely form that would be implicated in the event of a bioterrorist attack. Variola virus is a double stranded virus that causes smallpox. There has been a vaccination developed which eradicated this disease in 1977 and the WHO declared the world smallpox-free in 1980. It was typically transmitted through droplets or direct contact with scabs. Question Difficulty: Level 7

Given a situation where screening cells, major crossmatch, autocontrol, and DAT (anti-IgG) are all positive, what procedure should be performed next? A. Adsorption using rabbit stroma B. Antigen typing of patient cells C. Elution followed by a cell panel on the eluate D. Selected cell panel

C A positive DAT using anti-IgG indicates that antibodies are coating the patient cells. An eluate would be helpful to remove the antibody, followed by a cell panel in order to identify it. Harr, Robert R. Medical Laboratory Science Review (Page 142). F.A. Davis Company. Kindle Edition.

Which immunfluorescence pattern indicates the need for ENA testing by Ouchterlony immunodiffusion, Multiplex, or ELISA assays? A. Homogeneous or solid B. Peripheral or rim C. Speckled D. Nucleolar

C A speckled pattern is often due to the presence of antibodies against the extractable nuclear antigens, such as Sm, RNP, SSA, and SSB. Homogenous and rim patterns suggest antibodies to double-stranded DNA. The homogeneous pattern may also be seen with antibodies to deoxyribonuclear protein, which is not an ENA. Nucleolar patterns often indicate antibodies to RNA or fibrillarin. Harr, Robert R. Medical Laboratory Science Review (Page 100). F.A. Davis Company. Kindle Edition.

Screening cells, major crossmatch, and patient autocontrol are positive in all phases. Identify the problem. A. Specific cold alloantibody B. Specific cold autoantibody C. Abnormal protein or nonspecific autoantibody D. Cold and warm alloantibody mixture

C An abnormal protein or nonspecific autoantibody would cause antibody screen, crossmatch, and patient autocontrol to be positive. Alloantibodies would not cause a positive patient autocontrol. Harr, Robert R. Medical Laboratory Science Review (Page 142). F.A. Davis Company. Kindle Edition.

Protozoan cysts were seen in a concentration sediment and tentatively identified as Entamoeba coli. However, the organisms were barely visible on the permanent stained smear because: A. The organisms were actually not present in the concentrate sediment B. There were too few cysts to allow identification on the stained smear C. E. coli cysts were present but poorly fixed D. The concentrate and permanent stained smear were not from the same patient

C As E. coli cysts mature, the cyst wall becomes more impenetrable to fixatives. Consequently, the cysts may be visible in the concentrate sediment but appear very distorted or pale on the permanent stained smear. Harr, Robert R. Medical Laboratory Science Review (Page 471). F.A. Davis Company. Kindle Edition.

How would autoantibodies affect compatibility testing? A. No effect B. The DAT would be positive C. ABO, Rh, antibody screen, and crossmatch may show abnormal results D. Results would depend on the specificity of autoantibody

C Autoantibodies may cause positive reactions with screening cells, panel cells, donor cells, and patient cells. The DAT will be positive; however, the DAT is not included in compatibility testing. Harr, Robert R. Medical Laboratory Science Review (Page 140). F.A. Davis Company. Kindle Edition.

Confirmation of an infection with microsporidia can be achieved by seeing: A. The oocyst wall B. Sporozoites within the spore C. Evidence of the polar tubule D. Organisms stained with modified acid-fast stains

C Confirmation of an infection with microsporidial spores can be achieved by seeing evidence of the polar tubule within the spores (horizontal or diagonal line across/within the spore). Harr, Robert R. Medical Laboratory Science Review (Page 474). F.A. Davis Company. Kindle Edition.

Cryoprecipitate may be used to treat all of the following, except: A. von Willebrand's disease B. Hypofibrinogenemia C. Idiopathic thrombocytopenic purpura (ITP) D. Factor XIII deficiency

C Cryoprecipitate may be used to treat von Willebrand's disease, hypofibrinogenemia, and factor XIII deficiency, but is not indicated in ITP. IVIG is the product of choice for ITP. Harr, Robert R. Medical Laboratory Science Review (Page 151). F.A. Davis Company. Kindle Edition.

Patients with severe diarrhea should use "enteric precautions" to prevent nosocomial infections with: A. Giardia lamblia B. Ascaris lumbricoides C. Cryptosporidium spp. D. Cystoisospora belli

C Cryptosporidium oocysts (unlike those of C. belli) are immediately infective when passed in stool, and nosocomial infections have been well documented with this coccidian. Harr, Robert R. Medical Laboratory Science Review (Page 472). F.A. Davis Company. Kindle Edition.

In which case would eGFR derived from the plasma creatinine likely give a more accurate measure of GFR than measurement of plasma cystain C? A. Diabetic patient B. Chronic renal failure C. Post-renal transplant D. Chronic hepatitis

C Cystatin C is eliminated almost exclusively by the kidneys and plasma levels are not dependent on age, sex, or nutritional status. However, plasma levels are affected by some drugs, including those used to prevent renal transplant rejection. Increased plasma levels have been reported in chronic inflammatory diseases and cancer. Formulas are available to calculate eGFR from plasma cystatin C, but unlike for creatinine, the formulas must be matched to the method of assay. The eGFR derived from cystatin C can detect a fall in GFR sooner and may be more sensitive for diabetic and other populations at risk for chronic kidney disease. As a screening test for eGFR, it has about the same predictive value as eGFR derived from creatinine. Harr, Robert R. Medical Laboratory Science Review (Page 240). F.A. Davis Company. Kindle Edition.

A Gram stain from a gum lesion showed what appeared to be amoebae. A trichrome smear showed amoebae with a single nucleus and partially digested PMNs. The correct identification is: A. Trichomonas tenax B. Entamoeba histolytica/E. dispar C. Entamoeba gingivalis D. Entamoeba polecki

C E. gingivalis is known to be an inhabitant of the mouth and is characterized by morphology that resembles Entamoeba histolytica/E. dispar. However, E. gingivalis tends to ingest PMNs, whereas Entamoeba histolytica/E. dispar do not. Harr, Robert R. Medical Laboratory Science Review (Page 464). F.A. Davis Company. Kindle Edition.

Which method of analysis is considered the most reliable means of detecting mutations of BRCA, p53, BRAF, and other genes linked to cancer? A. FISH B. Immunohistochemistry C. Sequencing D. STR analysis

C Genes such as BRCA1 and BRCA2 are large and thousands of point mutations have been identified, making it impossible to perform an assay using DNA probes. When many mutations of a gene are possible, the most widely used detection method is sequencing. Next generation sequencing has made clinical applications affordable. The process involves creating a library of templates, copying them by PCR, separating the copied strands, and determining their base order by PCR using a reversible dye termination reaction. When a fluorescent-labeled nucleotide is added a laser determines its emission and the base is identified. The blocking group and fluorescent dye are removed and the process repeated for the next base added. Harr, Robert R. Medical Laboratory Science Review (Page 521). F.A. Davis Company. Kindle Edition.

β-Hemolytic streptococci, more than 50,000 col/mL, were isolated from a urinary tract catheter urine specimen. Given the following reactions, what is the most likely identification? CAMP test = Neg Hippurate hydrolysis = ± Bile solubility = Neg 6.5% salt = + PYR = + Bile esculin = + SXT = Resistant Bacitracin = Resistant Optochin = Resistant A. Group A streptococci B. Group B streptococci C. Enterococcus faecalis D. Nongroup A, nongroup B, nongroup D streptococci

C Group A streptococci are sensitive to bacitracin and negative for bile esculin and 6.5% salt broth. Group B streptococci will grow in 6.5% salt broth but are negative for bile esculin and PYR. The nongroup A, B, or D streptococci will not grow in 6.5% salt broth and are sensitive to SXT. Some group D streptococci will hydrolyze hippurate. Enterococcus faecalis is positive for bile esculin, 6.5% salt broth, and PYR. Harr, Robert R. Medical Laboratory Science Review (Page 422). F.A. Davis Company. Kindle Edition.

A technologist performs an antibody study and finds 1+ and weak positive reactions for several of the panel cells. The reactions do not fit a pattern. Several selected panels and a patient phenotype do not reveal any additional information. The serum is diluted and retested, but the same reactions persist. What type of antibody may be causing these results? A. Antibody to a high-frequency antigen B. Antibody to a low-frequency antigen C. High titer low avidity (HTLA) D. Anti-HLA

C HTLA antibodies may persist in reaction strength, even when diluted. These antibodies are directed against high-frequency antigens (such as Cha ). They are not clinically significant but, when present, are responsible for a high incidence of incompatible crossmatches. Harr, Robert R. Medical Laboratory Science Review (Page 137). F.A. Davis Company. Kindle Edition.

A patient's blood gas results are as follows: pH = 7.26, dCO2 = 2.0 mmol/L, HCO3- = 29 mmol/L These results would be classified as: A. Metabolic acidosis B. Metabolic alkalosis C. Respiratory acidosis D. Respiratory alkalosis

C Imbalances are classified as respiratory when the primary disturbance is with PCO2 because PCO2 is regulated by ventilation. PCO2 = dCO2 /0.03 or 60 mm Hg (normal 35-45 mm Hg). Increased dCO2 will increase hydrogen ion concentration, causing acidosis. Bicarbonate is moderately increased, but a primary increase in NaHCO3 causes alkalosis. Thus, the cause of this acidosis is CO2 retention (respiratory acidosis), and it is partially compensated by renal retention of bicarbonate. Harr, Robert R. Medical Laboratory Science Review (Page 193). F.A. Davis Company. Kindle Edition.

If too small a peak-trough difference is seen for a drug given orally, then: A. The dose should be decreased B. Time between doses should be decreased C. Dose interval should be increased D. Dose per day and time between doses should be decreased

C Increasing the dosing interval will reduce the trough concentration of the drug, and increasing the dose will increase the peak concentration of the drug, resulting in a greater peak-trough difference. The peak-trough ratio is usually adjusted to 2 with the dose interval set to equal the drug half-life. Under these conditions, both peak and trough levels often fall within the therapeutic range. Harr, Robert R. Medical Laboratory Science Review (Page 296). F.A. Davis Company. Kindle Edition.

A 6-year-old female patient was admitted to the hospital following 2 days of severe diarrhea. Cultures from three consecutive stool samples contained blood and mucus. Patient history revealed a hamburger lunch at a fast-food restaurant 3 days earlier. Which pathogen is most likely responsible for the following results? Growth on: XLD agar = yellow colonies HE agar = yellow colonies Mac agar = light pink and dark pink colonies Mac with sorbitol agar - few dark pink and many colorless colonies A. Salmonella spp. B. Shigella spp. C. E. coli O157:H7 D. Yersinia enterocolitica

C Inflammation with bleeding of the mucosa of the large intestine (hemorrhagic colitis) is a result of an enterohemorrhagic E. coli (EHEC) infection associated with certain serotypes, such as E. coli O157:H7. The source of the E. coli infection is from ingestion of undercooked ground beef contaminated with fecal matter or drinking raw milk. Harr, Robert R. Medical Laboratory Science Review (Page 398). F.A. Davis Company. Kindle Edition.

A technologist removed 4 units of blood from the blood bank refrigerator and placed them on the counter. A clerk was waiting to take the units for transfusion. As she checked the paperwork, she noticed that one of the units was leaking onto the counter. What should she do? A. Issue the unit if the red cells appear normal B. Reseal the unit C. Discard the unit D. Call the medical director and ask for an opinion

C Leaking may indicate a broken seal or a puncture, which indicates possible contamination of the unit, even if the red cells appear normal. The unit should be discarded. Harr, Robert R. Medical Laboratory Science Review (Page 141). F.A. Davis Company. Kindle Edition.

A gram-positive coccus recovered from a wound ulcer from a 31-year-old diabetic patient showed pale yellow, creamy, β-hemolytic colonies on blood agar. Given the following test results, what is the most likely identification? Catalase = + Glucose OF: positive open tube, negative sealed tube Mannitol salt = Neg Slide coagulase = Neg A. Staphylococcus aureus B. Staphylococcus epidermidis C. Micrococcus spp. D. Streptococcus spp.

C Micrococcus spp. utilize glucose oxidatively but not under anaerobic conditions (sealed tube). Staphylococcus spp. utilize glucose oxidatively and anaerobically. The catalase differentiates the Micrococcaceae family (positive) from the Streptococcaceae family (negative). Harr, Robert R. Medical Laboratory Science Review (Page 419). F.A. Davis Company. Kindle Edition.

Which of the following conditions will prevent any migration of proteins across an electrophoretic support medium such as agarose? A. Using too high a voltage B. Excessive current during the procedure C. Loss of contact between a buffer chamber and the medium D. Evaporation of solvent from the surface of the medium

C Movement of proteins is dependent upon the presence of a salt bridge that allows current to flow via transport of ions to the electrodes across the support medium. If the salt bridge is not intact, there will be no migration, even if voltage is maintained across the electrodes. For agarose and cellulose acetate, heat causes evaporation of solvent from the buffer. This increases the ionic strength, causing current to rise during the run. Excessive heat can damage the support medium and denature proteins. Power = E (voltage) × I (current) × t (time); since E = I × R (resistance), heat is proportional to the square of current (P = I 2 × R × t). Constant current or power mode is used for long runs to prevent heat damage. Harr, Robert R. Medical Laboratory Science Review (Page 248). F.A. Davis Company. Kindle Edition.

An antibody is detected in a pregnant woman and is suspected of being the cause of fetal distress. The antibody reacts at the IAT phase but does not react with DTT-treated cells. This antibody causes in vitro hemolysis. What is the most likely antibody specificity? A. Anti-Le^a B. Anti-Lu^a C. Anti-Lu^b D. Anti-Xg^a

C Of the antibodies listed, only Lu b is detected in the IAT phase, causes in vitro hemolysis, may cause HDN, and does not react with DTT-treated cells. Harr, Robert R. Medical Laboratory Science Review (Page 137). F.A. Davis Company. Kindle Edition.

A PCR reaction is performed, and the negative control demonstrates the presence of a detectable number of PCR products (amplicons) by capillary electrophoresis. What is the most likely cause? A. False-positive post-PCR hybridization reaction due to low stringency B. Dimerization of PCR primers C. Contamination of control sample with a trace amount of template DNA D. Background signal from gel fluorescence or inadequate removal of unbound probe

C PCR and other methods of DNA amplification have a great potential for error caused by contamination of sample or reagents with template DNA. This can derive from other samples, positive controls, or amplicons from preceding samples, but the most common source of contamination is by amplicons. Each run must contain a negative (as well as positive) control. The negative control contains all PCR reagents except the template DNA and should produce no detectable amplicons. However, PCR reactions that detect product by enzymatic, fluorescent, or chemiluminescent methods instead of gel or capillary electrophoresis will generate a signal for the negative control. This signal should be comparable to that for a substrate blank. Signals above a predetermined cutoff point will invalidate the test. Harr, Robert R. Medical Laboratory Science Review (Page 504). F.A. Davis Company. Kindle Edition.

A serum thyroid panel reveals an increase in total T4 , normal TSH, and normal free T4 . What is the most likely cause of these results? A. Primary hyperthyroidism B. Secondary hyperthyroidism C. Euthyroid with increased thyroxine-binding protein D. Subclinical hypothyroidism

C Patients with a normal TSH are euthyroid, and most commonly an increase in total T 4 in these patients is caused by an increase in TBG. An increase in TBG causes an increase in total T 4 but not free T 4 . Subclinical hypothyroidism is usually associated with a high TSH, but normal free T 3 and free T 4 . When TSH is indeterminate, the diagnosis is made by demonstrating an exaggerated response to the TRH stimulation test. Harr, Robert R. Medical Laboratory Science Review (Page 292). F.A. Davis Company. Kindle Edition.

What protocol is followed when screening whole blood donors for HIV-1 RNA? A. Pools of 10 are tested; if the pool is nonreactive, donors are accepted B. Pools of 20 are tested; if the pool is reactive, samples are tested individually C. Pools of up to 16 donors are tested; if pool is reactive, individual samples are screened D. All donors are screened individually; if samples are reactive, blood is discarded

C Pools of up to 16 donors are tested by nucleic acid amplification technology. If the pool is reactive, samples from each individual donor are tested. Harr, Robert R. Medical Laboratory Science Review (Page 162). F.A. Davis Company. Kindle Edition.

Which of the following conditions is most likely to cause a falsely low L/S ratio? A. The presence of PG in amniotic fluid B. Freezing the specimen for one month at -20°C C. Centrifugation at 1,000 × g for 10 minutes D. Maternal diabetes mellitus

C Pulmonary surfactants are largely present in the form of lamellar bodies and can be lost by centrifuging the amniotic fluid at high g force. Centrifuge speed should be the minimum required to spin down cells (450 g for 10 minutes at 4°C). Samples that cannot be measured immediately should be refrigerated or frozen. Samples are stable for up to 3 days at 2°C-8°C and for months when frozen at -20°C or lower. Meconium and blood may also introduce errors when measuring the L/S ratio. Blood has an L/S ratio of approximately 2:1 and will falsely raise the L/S ratio when fetal lungs are immature and depress the L/S ratio when fetal lungs are mature. Harr, Robert R. Medical Laboratory Science Review (Page 363). F.A. Davis Company. Kindle Edition.

Should an O-negative mother receive RhIg if a positive DAT on the newborn is caused by immune anti-A? A. No, the mother is not a candidate for RhIg because of the positive DAT B. Yes, if the baby's type is Rh negative C. Yes, if the baby's type is Rh positive D. No, the baby's problem is unrelated to Rh blood group antibodies

C RhIg is immune anti-D and is given to Rh-negative mothers who give birth to Rh-positive babies and who do not have anti-D already formed from previous pregnancies or transfusion. Harr, Robert R. Medical Laboratory Science Review (Page 159). F.A. Davis Company. Kindle Edition.

Which statement about CF is accurate? A. A sweat chloride test is abnormal in all forms of CF B. Immunoreactive trypsin is deficient in all persons with CF C. Some CF mutations can cause male infertility with no other symptoms D. The CF genotype always predicts the severity of the disease

C Serum immunoreactive trypsin is the recommended screening test for CF, but pancreatic insufficiency is not found in about 15% of CF cases. An abnormal result is confirmed by sweat chloride testing. Some infants may be too young for accurate sweat testing, and some mild forms of CF may give indeterminate results. DNA testing can be used in these cases. The CF genotype is not predictive of phenotype in most cases (an exception being ΔF508, which is almost always associated with pancreatic disease). CF mutations are responsible for about 75% of congenital bilateral absence of the vas deferens. Affected persons have at least one abnormal CF gene. Other than infertility, they are asymptomatic and may or may not have a sweat chloride level above 65 mmol/L. Harr, Robert R. Medical Laboratory Science Review (Page 515). F.A. Davis Company. Kindle Edition.

Which test may be used to monitor LMWH therapy? A. APTT B. INR C. Anti-Xa heparin assay D. Activated clotting time

C The anti-factor Xa heparin assay is used to monitor LMWH therapy when required because the APTT test is insensitive to LMWH. The assay can be performed by chromogenic end-point detection used on automated analyzers. The principle of the test is to measure the inhibition of Xa by heparin. The reagent is a mixture of a fixed concentration of factor Xa, a substrate which is specific for factor Xa, and a fixed concentration of antithrombin (AT). Some kits rely on the antithrombin in patient's plasma. Heparin forms a complex with AT and factor Xa (AT-heparin-Xa). Excess free factor Xa cleaves the chromogenic substrate and releases a yellow product. The color intensity of the product is inversely proportional to plasma heparin concentration, and is measured by a photodetector at 405 nm. LMWH therapy does not usually require monitoring; however, exceptions include pediatric, obese, and pregnant patients and those with renal failure. Harr, Robert R. Medical Laboratory Science Review (Page 64). F.A. Davis Company. Kindle Edition.

Which of the following results are discrepant? A. Small amount of blood but negative protein B. Moderate amount of blood but no RBCs in microscopic exam C. Negative blood but 6-10 RBCs/high-power field (HPF) D. Negative blood, positive protein

C The blood test detects as little as 0.015 mg/dL free hemoglobin and 4-5 RBCs/μL. The protein test detects 15 mg/dL albumin but substantially more hemoglobin is required to give a positive test. Therefore, a small blood reaction (nonhemolyzed or moderately hemolyzed trace, trace, or small) usually occurs in the absence of a positive protein. A positive blood test often occurs in the absence of RBCs in the microscopic exam. This can result from intravascular hemolysis, myoglobinuria, or lysis of RBCs caused by alkaline or hypotonic urine. A positive test for protein and a negative blood test occurs commonly in conditions such as orthostatic albuminuria, urinary tract infection, and diabetes mellitus. However, a negative blood test should not occur if more than 3-4 RBCs per HPF are seen in the microscopic. Either the blood test is falsely negative (a missed nonhemolyzed trace) or yeast have been mistaken for RBCs. Harr, Robert R. Medical Laboratory Science Review (Page 339). F.A. Davis Company. Kindle Edition.

Early ring stages of the fifth human malaria, Plasmodium knowlesi, resemble those of: A. Plasmodium malariae B. Plasmodium ovale C. Plasmodium falciparum D. Plasmodium vivax

C The early ring stages of Plasmodium knowlesi resemble those of P. falciparum. Harr, Robert R. Medical Laboratory Science Review (Page 474). F.A. Davis Company. Kindle Edition.

Six units are crossmatched. Five units are compatible, one unit is incompatible, and the recipient's antibody screen is negative. Identify the problem: A. Patient may have an alloantibody to a high-frequency antigen B. Patient may have an abnormal protein C. Donor unit may have a positive DAT D. Donor may have a high-frequency antigen

C The incompatible donor unit may have an antibody coating the red cells, or the patient may have an alloantibody to a low-frequency antigen. An alloantibody to a high-frequency antigen would agglutinate all units and screening cells. Harr, Robert R. Medical Laboratory Science Review (Page 142). F.A. Davis Company. Kindle Edition.

A PCR analysis of a vaginal sample for Chlamydia trachomatis gives a negative result (optical density of biotinylated reaction product below the cutoff point). The internal control result is also below the cutoff. Positive and negative controls produced acceptable results. What action should be taken? A. The test should be reported as negative B. The sample should be diluted and the test repeated C. The result should not be reported and the sample should be repeated D. A preliminary result of negative should be reported but should be confirmed by further testing using a different method of analysis

C The internal control in PCR is an oligonucleotide sequence different from that of the target but that binds the same primers. Its product is detected using a different probe than is used for the target sequence. If the internal control is not amplified, this indicates an invalid test. Causes include the presence of a PCR inhibitor, denaturation of the polymerase, hybridization failure, or error in the detection system (e.g., improper pH preventing enzyme-conjugated streptavidin from acting on the substrate). The assay of this sample must be repeated. Harr, Robert R. Medical Laboratory Science Review (Page 505). F.A. Davis Company. Kindle Edition.

A tissue sample for DNA analysis by PCR was processed for DNA by simple lysis and proteinase K digestion. The lysate was diluted 1:100 and its absorbance measured in an ultraviolet spectrophotometer at 260 nm and 280 nm. The absorbance ratio 260:280 was 1.2. What does this indicate? A. The DNA concentration is too high for PCR B. The DNA concentration is too low for PCR C. The sample contains too much protein D. The sample is optimal for PCR

C The mass and purity of DNA affect the efficiency of DNA amplification. A common way to determine the amount of DNA recovered from a sample is to measure its absorbance at 260 nm, where the nitrogenous bases have an absorbance maximum. Based on the molar absorptivity of DNA at 260 nm, an absorbance of 1.0 equates to 50 ng/μL; thus, multiplying the absorbance by 50 and the dilution factor estimates the DNA concentration in ng/μL. However, proteins also absorb at 260 nm, and if present in sufficient amounts will cause overestimation of DNA and inhibit amplification. An absorbance maximum for protein is 280 nm owing to the phenolic rings of tyrosine and tryptophan. The absorbance ratio of 260:280 is a measure of protein contamination. If the ratio is below 1.7, then too much protein is present, and further purification is needed. Harr, Robert R. Medical Laboratory Science Review (Page 520). F.A. Davis Company. Kindle Edition.

When malaria smears are requested, what patient information should be obtained? A. Diet, age, sex B. Age, antimalarial medication, sex C. Travel history, antimalarial medication, date of return to United States D. Fever patterns, travel history, diet

C Travel history (areas of drug resistance), the date of return to the United States (primary versus relapse case), and history of antimalarial medication and illness (severe illness, few organisms on smear) are very important questions to ask. Without this information, a malaria diagnosis can be missed or delayed with severe patient consequences. Harr, Robert R. Medical Laboratory Science Review (Page 472). F.A. Davis Company. Kindle Edition.

A 13-year-old boy was admitted to the hospital with a diagnosis of viral encephalitis. History revealed that the boy harbored wild raccoons from nearby woods. What is the best method to determine if the boy has contracted rabies? A. Remove the brainstems from all of the raccoons and examine for cytopathic effects B. Request immunofluorescent test for antibody on the saliva from all of the raccoons C. Request immunofluorescent test for antigen in cutaneous nerves obtained by nuchal biopsy of the patient D. Isolate the virus from the saliva of both the animals and the patient

C Using direct immunofluorescence, rabies antigen can be detected in the cutaneous nerves surrounding the hair follicles of the posterior region of the neck (nuchal biopsy) and in epithelial cells obtained by a corneal impression. Antibodies to rabies can be detected in the serum and CSF of infected persons within 8-10 days of illness; however, infection usually occurs several months before the onset of symptoms. Isolation of virus from the saliva of the patient may be accomplished by mouse inoculation or by inoculation of susceptible cell culture lines with subsequent detection by immunofluorescent antibodies. Harr, Robert R. Medical Laboratory Science Review (Page 458). F.A. Davis Company. Kindle Edition.

SITUATION: A specimen for CK performed on an automated analyzer using an optimized Oliver-Rosalki method gives an error flag indicating substrate depletion. The sample is diluted 1:2 and 1:4 by the serial dilution technique and reassayed. After correcting for the dilution, the results are as follows: 1:2 Dilution = 3,000 IU/L 1:4 Dilution = 3,600 IU/L Dilutions are made a second time and assayed again but give identical results. What is the most likely explanation? A. The serum became contaminated prior to making the 1:4 dilution B. The wrong pipet was used to make one of the dilutions C. An endogenous competitive inhibitor is present in the serum D. An error has been made in calculating the enzyme activity of one of the two dilutions

C When a competitive inhibitor is present in the serum, a dilution of the sample will cause an increase in the reaction rate by reducing the concentration of the inhibitor. Dilution of serum frequently increases the activity of CK and amylase. The same effect will occur when a smaller volume of serum is used in the assay because less inhibitor will be present in the reaction mixture. Harr, Robert R. Medical Laboratory Science Review (Page 266). F.A. Davis Company. Kindle Edition.

A Mycobacterium species recovered from a patient with AIDS gave the following results: Niacin = Neg T2H = + Tween 80 hydrolysis = Neg Nitrate reduction = Neg Heat-stable catalase (68°C) = ± Nonphotochromogen What is the most likely identification? A. M. gordonae B. M. bovis C. M. avium-intracellulare complex D. M. kansasii

C With the exception of M. tuberculosis, M. avium-intracellulare (MAI) complex is the Mycobacterium species most often isolated from AIDS patients. It is biochemically inert, which is a distinguishing factor for identification. MAI complex is highly resistant to the antibiotics used to treat tuberculosis, including multidrug therapy. Treatment with streptomycin, rifampin, ethionamide, ethambutol with cycloserine, or kanamycin has shown little success. Harr, Robert R. Medical Laboratory Science Review (Page 441). F.A. Davis Company. Kindle Edition.

From the following organisms, which one is considered to be the LEAST pathogenic to humans? Corynebacterium ulcerans Bacillus anthracis Listeria monocytogenes Nocardia brasiliensis

Corynebacterium ulcerans Corynebacterium ulcerans is correct because this organism is considered a zoonosis and can only occur with close animal contact and human infections are rare. This organism has been linked to causing bovine mastitis. Bacillus anthracis, Listeria monocytogenes, and Nocardia brasiliensishave been linked to causing serious human infections. Bacillus anthracis is the most virulent organism listed. Persons with cutaneous anthrax may have a 20% chance of fatality if untreated; virtually 100% of those with inhalation anthrax will succumb to the infection. Listeria monocytogenes can cause human infections through contaminated food or neonatal infections from colonized mothers during pregnancy. Nocardia brasiliensis can cause subcutaneous infections such as actinomycetoma that tend to remain localized to the skin. Question Difficulty: Level 8

SITUATION: Urinalysis of a sample from a patient suspected of having a transfusion reaction reveals small yellow-brown crystals in the microscopic examination. Dry reagent strip tests are normal with the exception of a positive blood reaction (moderate) and trace positive protein. The pH of the urine is 6.5. What test should be performed to positively identify the crystals? A. Confirmatory test for bilirubin B. Cyanide-nitroprusside test C. Polarizing microscopy D. Prussian blue stain

D A positive blood test and trace protein occurring with a normal test for urobilinogen and an absence of RBCs are consistent with an intravascular transfusion reaction. Small yellow-brown granular crystals at an acid pH may be uric acid, bilirubin, or hemosiderin. Bilirubin crystals are ruled out by the negative dry reagent strip test for bilirubin. Potassium ferrocyanide is used in the Prussian blue staining reaction to detect hemosiderin deposits in urinary sediment. Hemosiderin is associated with hemochromatosis and increased RBC destruction. Causes of urinary hemosiderin include transfusion reaction, hemolytic anemia, and pernicious anemia. Harr, Robert R. Medical Laboratory Science Review (Page 346). F.A. Davis Company. Kindle Edition.

Which would be consistent with partially compensated respiratory acidosis? A. pH increased, PCO2 increased, Bicarbonate increased B. pH increased, PCO2 decreased, Bicarbonate decreased C. pH decreased, PCO2 decreased, Bicarbonate decreased D. pH decreased, PCO2 increased, Bicarbonate increased

D Acidosis = low pH; respiratory = disturbance of PCO2 ; a low pH is caused by increased PCO2 . In partially compensated respiratory acidosis, the metabolic component of the buffer system, bicarbonate, is retained. This helps to compensate for retention of PCO2 by titrating hydrogen ions. The compensatory component always moves in the same direction as the cause of the acid-base disturbance. Harr, Robert R. Medical Laboratory Science Review (Page 194). F.A. Davis Company. Kindle Edition.

SITUATION: An immunology supervisor ordered several antinuclear antibody and influenza A kits. The outside packaging of both kits was marked to store at 2° C-8° C. The kits were shipped with dry ice, but were unpacked at 7:00 p.m. and left in the mailroom at room temperature until 7:00 a.m. the next morning. What should be done with the kits? A. They can be placed into inventory B. They must be tested using quality controls before use and used only if QC performance is acceptable C. The kits should not be used for clinical testing D. The disposition of the kits depends on the manufacturer's documentation for stability and the lab's lot-to-lot analysis

D All laboratory kits and reagents must be stored according to the manufacturer's instructions. The manufacturer should be consulted to determine if storage time and temperature limits have been established for the kits. If these have not been exceeded, and the lot-to-lot analysis confirms that they are unaffected, then the kits may be used. Harr, Robert R. Medical Laboratory Science Review (Page 534). F.A. Davis Company. Kindle Edition.

SITUATION: An O-negative mother gave birth to a B-positive infant. The mother had no history of antibodies or transfusion. This was her first child. The baby was mildly jaundiced and the DAT weakly positive with polyspecific antisera. What could have caused the positive DAT? A. Anti-D from the mother coating the infant red cells B. An alloantibody, such as anti-K, coating the infant red cells C. Maternal anti-B coating the infant cells D. Maternal anti-A, B coating the infant cells

D Anti-A,B is an IgG antibody and can cross the placenta and attach to infant cells. It is known as a single entity as opposed to separate antibodies. Anti-D would not be the cause because this is the first pregnancy. Anti-K is not the cause because there is no history of alloantibodies or past transfusions. Harr, Robert R. Medical Laboratory Science Review (Page 161). F.A. Davis Company. Kindle Edition.

SITUATION: A urine sample is received in the laboratory with the appropriate custody control form, and a request for drug of abuse screening. Which test result would be cause for rejecting the sample? A. Temperature after collection 95°F B. pH 5.0 C. Specific gravity 1.005 D. Creatinine 5 mg/dL

D Approximately 5 per 1,000 urine samples received for DAU testing have been adulterated by either dilution, substitution, or addition of substances such as glutaraldehyde that interfere with testing. The majority of these situations can be detected by determining temperature (90°F-100°F) pH (4.5-8.0), specific gravity (1.003-1.019), and creatinine (≥20 mg/dL). All of the values listed are within the limits of an acceptable sample with the exception of creatinine. Dry reagent strips are available that test for pH, specific gravity, creatinine, nitrite, peroxide, pyridinium, and glutaraldehyde. Harr, Robert R. Medical Laboratory Science Review (Page 300). F.A. Davis Company. Kindle Edition.

Autofluorescence requires no stain and is recommended for the identification of: A. Entamoeba histolytica cysts B. Toxoplasma gondii tachyzoites C. Dientamoeba fragilis trophozoites D. Cyclospora cayetanensis oocysts

D Autofluorescence requires no stain and is often recommended for confirmation of Cyclospora cayetanensis oocysts. Harr, Robert R. Medical Laboratory Science Review (Page 475). F.A. Davis Company. Kindle Edition.

After returning from a 2-year stay in India, a patient has eosinophilia, an enlarged left spermatic cord, and bilateral inguinal lymphadenopathy. The most likely clinical specimen and organism match is: A. Thin blood films—Leishmania B. Urine—concentration for Trichomonas vaginalis C. Thin blood films—Babesia D. Thick blood films—microfilariae

D Based on the history, the most relevant procedure to perform is the preparation and examination of thick blood films for the recovery and identification of microfilariae. The symptoms suggest early filariasis. Harr, Robert R. Medical Laboratory Science Review (Page 472). F.A. Davis Company. Kindle Edition.

A 45-year-old hunter developed fever, myalgia, and periorbital edema. He has a history of bear meat consumption. The most likely causative agent is: A. Toxoplasma gondii B. Taenia solium C. Hymenolepis nana D. Trichinella spiralis

D Bear meat is another excellent source of T. spiralis. In this case, the patient had evidently consumed poorly cooked bear meat, thus ingesting the encysted larvae of T. spiralis. Harr, Robert R. Medical Laboratory Science Review (Page 471). F.A. Davis Company. Kindle Edition.

SITUATION: A physician calls to request a CK on a sample already sent to the laboratory for coagulation studies. The sample is 2-hour-old citrated blood and has been stored at 4°C. The plasma shows very slight hemolysis. What is the best course of action and the reason for it? A. Perform the CK assay on the sample because no interferent is present B. Reject the sample because it is slightly hemolyzed C. Reject the sample because it has been stored too long D. Reject the sample because the citrate will interfere

D CK activity is lost with excessive storage, the most labile isoenzyme being CK-1. However, CK in serum is stable at room temperature for about 4 hours and up to 1 week at 4°C provided that an optimized method is used. Slight hemolysis does not interfere because CK is absent from RBCs. More significant hemolysis may cause positive interference by contributing ATP, glucose-6-PO4 , and adenylate kinase to the serum. Calcium chelators remove magnesium as well as calcium and should not be used. Harr, Robert R. Medical Laboratory Science Review (Page 267). F.A. Davis Company. Kindle Edition.

Upon direct examination of a sputum specimen, several spherules were noted that contained endospores. Growth on Sabouraud-dextrose agar showed aerial mycelial elements. The septate hyphae produced barrel-shaped arthroconidia. What is the most likely identification? A. Penicillium marneffei B. Scopulariopsis spp. C. Cryptococcus neoformans D. Coccidioides immitis

D Coccidioides immitis endospores are often confused with yeast cells but they do not bud. C. immitis is endemic in the southwestern United States. Since the arthroconidia are highly infectious, an open plate should not be used, and a slide culture test should not be performed. Rather, tubed media is used for testing, and all work should be performed in a biological safety cabinet. Harr, Robert R. Medical Laboratory Science Review (Page 453). F.A. Davis Company. Kindle Edition.

A new laboratory information system (LIS) will be evaluated by the laboratory staff. Which of the following points should be considered in the evaluation? A. Cost of updating software B. Interface ability with existing laboratory instruments C. Tracking of uncrossmatched blood units in Blood Bank D. All of these options

D Each laboratory will have specific needs to determine the appropriate LIS. However, storage capacity, reliability, security, upgrade costs, instrument interface availability, inventory management, and quality control functions are common parameters that must be considered. Harr, Robert R. Medical Laboratory Science Review (Page 532). F.A. Davis Company. Kindle Edition.

Toxoplasma gondii is characterized by: A. Possible congenital infection and ingestion of oocysts B. Cosmopolitan distribution and possible difficulties with interpretation of serological results C. Neither A nor B D. Both A and B

D Infection with T. gondii is acquired through the ingestion of rare or raw meats, infective oocysts from cat feces, or as a congenital transmission. The organism has a cosmopolitan distribution and although serological testing is generally the test of choice, the results may be very difficult to interpret in certain situations (e.g., congenital infection and immunocompromised patients). Harr, Robert R. Medical Laboratory Science Review (Page 467). F.A. Davis Company. Kindle Edition.

A leg culture from a nursing home patient grew gram-negative rods on MacConkey agar as pink to dark pink oxidase-negative colonies. Given the following results, which is the most likely organism? TSI = A/A Indole = Neg MR = Neg VP = + Citrate = + H2 S = Neg Urease = + Motility = Neg Antibiotic susceptibility: resistant to carbenicillin and ampicillin A. Serratia marcescens B. Proteus vulgaris C. Enterobacter cloacae D. Klebsiella pneumoniae

D K. pneumoniae and E. cloacae display similar IMViC (indole, MR, VP, and citrate) reactions (00++) and TSI results. However, approximately 65% of E. cloacae strains are urease positive compared with 98% of those of K. pneumoniae. Enterobacter spp. are motile and Klebsiella are nonmotile. The antibiotic pattern of resistance to carbenicillin and ampicillin is characteristic for Klebsiella. Harr, Robert R. Medical Laboratory Science Review (Page 397). F.A. Davis Company. Kindle Edition.

A 12-year-old girl is brought to the emergency department with meningitis and a history of swimming in a warm-water spring. Motile amoebae that measure 10 μin size are seen in the CSF and are most likely: A. Iodamoeba bütschlii trophozoites B. Endolimax nana trophozoites C. Dientamoeba fragilis trophozoites D. Naegleria fowleri trophozoites

D N. fowleri are free-living soil and water amoebae that cause primary amoebic meningoencephalitis, or PAM. The number of cases reported is few; however, the infection is very acute and almost always fatal. Harr, Robert R. Medical Laboratory Science Review (Page 465). F.A. Davis Company. Kindle Edition.

A 29-year-old male who often hunted rabbits and spent a lot of time in the woods was admitted to the hospital with skin ulcers on his upper extremities. At 48 hours, a small coccobacillus was recovered from the aerobic blood culture bottle only. The organism stained poorly with Gram stain, but did stain with acridine orange. Cultures taken from the ulcers did not grow on primary media. What is the most likely identification? A. Pseudomonas aeruginosa B. Pseudomonas fluorescens C. Chryseobacterium spp. D. Francisella tularensis

D Persons handling samples suspected of containing F. tularensis must wear gloves and use a biological safety cabinet (follow biosafety Level II controls). For cultures, biosafety Level III controls must be followed. Tularemia is one of the most common laboratory-acquired infections, and it is recommended that specimens be sent to a reference laboratory for identification and serological testing. F. tularensis requires cysteine and cystine to grow. It may grow on chocolate agar supplemented with IsoVitalex and also on charcoal yeast extract agar used to isolate Legionellae. Harr, Robert R. Medical Laboratory Science Review (Page 414). F.A. Davis Company. Kindle Edition.

A Staphylococcus spp. recovered from a wound (cellulitis) was negative for the slide coagulase test (clumping factor) and negative for novobiocin resistance. The next test(s) needed for identification is (are): A. Tube coagulase test B.β-Hemolysis on blood agar C. Mannitol salt agar plate D. All of these options

D S. aureus is novobiocin sensitive and cannot be ruled out by a negative clumping factor test. Most S. aureus produce β-hemolysis on sheep blood agar plates and are mannitol salt positive (produce acid and are not inhibited by the high salt concentration). The tube test should be performed because the slide test was negative. Harr, Robert R. Medical Laboratory Science Review (Page 419). F.A. Davis Company. Kindle Edition.

Urine cultured from the catheter of an 18-year-old female patient produced more than 100,000 col/mL on a CNA plate. Colonies were catalase positive, coagulase negative by the latex agglutination slide method as well as the tube coagulase test. The best single test for identification is: A. Lactose fermentation B. Urease C. Catalase D. Novobiocin susceptibility

D S. epidermidis and S. saprophyticus are the two possibilities because they are both catalase positive, coagulase negative, urease positive, and ferment lactose. Novobiocin susceptibility is the test of choice for differentiating these two species. S. epidermidis is sensitive but S. saprophyticus is resistant to 5 μg of novobiocin. Harr, Robert R. Medical Laboratory Science Review (Page 419). F.A. Davis Company. Kindle Edition.

Which method is used to determine if the hemoglobin C gene is present in fetal cells? A. Chromosome painting B. FISH C. Restriction enzyme analysis D. PCR followed by blotting with a specific oligonucleotide probe

D The base substitution of hemoglobin C does not affect the MstII restriction site and is not visible by FISH or other tests that detect damage to larger areas of the chromosome. PCR is used to amplify the gene region involved, and the product is tested by Southern blotting using a label-specific oligonucleotide probe. Harr, Robert R. Medical Laboratory Science Review (Page 518). F.A. Davis Company. Kindle Edition.

A moderate-positive blood test and trace protein test are seen on the dry reagent strip, and 11-20 red blood cells per high-power field are seen in the microscopic exam. These results are most likely caused by which of the following? A. Transfusion reaction B. Myoglobinuria C. Intravascular hemolytic anemia D. Recent urinary tract catheterization

D The blood test detects intact RBCs, hemoglobinuria, and myoglobinuria. Causes of hemoglobinuria include intravascular hemolytic anemias, transfusion reactions, and lysis of RBCs in the filtrate or urine caused by alkaline or hypotonic conditions. Causes of hematuria include acute and chronic glomerulonephritis, pyelonephritis, polycystic kidney disease, renal calculi, bladder and renal cancer, and postcatheterization of the urinary tract. Harr, Robert R. Medical Laboratory Science Review (Page 338). F.A. Davis Company. Kindle Edition.

A 25-year-old male patient was diagnosed with HIV-1 by enzyme immunoassay, testing positive twice, and the diagnosis was confirmed by Western blot testing. Which laboratory test should be performed prior to initiating antiviral therapy? A. Quantitative plasma virus concentration (viral load testing) B. Quantitation of CD4 lymphocytes C. Phenotype/genotype resistance testing D. All of these options

D The decision to initiate antiviral therapy is based upon the presence or absence of symptoms, CD4 lymphocyte count, and the viral load. For example, treatment is usually withheld from patients with CD4 counts > 350/μL and viral load < 55,000/mL and is instituted in asymptomatic patients if the CD4 count is < 200/μL regardless of viral load. Treatment failure within the first year with three-drug regimens is 35%-45%, and drug resistance testing (genotype and/or phenotype testing) is recommended to identify drug-resistant strains prior to initiating treatment. Harr, Robert R. Medical Laboratory Science Review (Page 460). F.A. Davis Company. Kindle Edition.

Which donor unit is selected for a recipient with anti-c? A. r'r B. R0R1 C. R2r' D. r'r^y

D The designation r´ is dCe and r y is dCE, neither of which contains the c antigen. The other three Rh types contain the c antigen and could not be used in transfusion for a person with anti-c. Harr, Robert R. Medical Laboratory Science Review (Page 130). F.A. Davis Company. Kindle Edition.

Which test result would be normal in a patient with dysfibrinogenemia? A. Thrombin time B. APTT C. PT D. Immunologic fibrinogen level

D The level of plasma fibrinogen determined immunologically is normal. In a patient with dysfibrinogenemia, fibrinogen is not polymerized properly, causing abnormal fibrinogen-dependent coagulation tests. Harr, Robert R. Medical Laboratory Science Review (Page 53). F.A. Davis Company. Kindle Edition.

The following results were obtained from a pure culture of gram-negative rods recovered from the pulmonary secretions of a 10-year-old cystic fibrosis patient with pneumonia: Oxidase = + Motility = + Glucose OF (open) = + Gelatin hydrolysis = + Pigment = Red Arginine dihydrolase = + (nonfluorescent) Growth at 42°C = + Flagella = + (polar, monotrichous) Which is the most likely organism? A. Burkholderia pseudomallei B. Pseudomonas stutzeri C. Burkholderia cepacia D. Pseudomonas aeruginosa

D The oxidase test and red pigment (pyorubin), as well as growth at 42°C, distinguish P. aeruginosa from the other pseudomonads listed, particularly B. cepacia, which is also associated with cystic fibrosis. Harr, Robert R. Medical Laboratory Science Review (Page 402). F.A. Davis Company. Kindle Edition.

A stated competency requirement for a medical laboratory science student is to perform calibration, plot data, and evaluate the acceptability of controls. This competency requirement encompasses which educational objective? A. Cognitive B. Psychomotor C. Affective D. All of these options

D The student will perform the actual calibration (psychomotor skills), utilize the cognitive domain of analysis to plot the standards, construct a best-fit calibration line, and determine the concentration of the controls. The affective domain describes the student's ability to value the results as acceptable or to repeat the calibration, if an error is apparent. Harr, Robert R. Medical Laboratory Science Review (Page 524). F.A. Davis Company. Kindle Edition.

A pure culture of β-hemolytic streptococci recovered from a leg wound ulcer gave the following reactions: CAMP test = Neg Hippurate hydrolysis = Neg Bile esculin = Neg 6.5% salt = Neg PYR = Neg Bacitracin = Resistant Optochin = Resistant SXT = Sensitive The most likely identification is: A. Group A streptococci B. Group B streptococci C. Enterococcus faecalis D. Nongroup A, nongroup B, nongroup D streptococci

D The β-hemolytic streptococci—not of groups A, B, or D—are sensitive to SXT and may be either sensitive or resistant to bacitracin. Groups A and B are both resistant to SXT. Group A and Enterococcus faecalis are PYR positive. Enterococcus faecalis is also positive for bile esculin and 6.5% salt broth. Harr, Robert R. Medical Laboratory Science Review (Page 422). F.A. Davis Company. Kindle Edition.

SITUATION: A cancer patient recently developed a severe infection. The patient's hemoglobin is 8 g/dL owing to chemotherapy with a drug known to cause bone marrow depression and immunodeficiency. Which blood products are indicated for this patient? A. Liquid plasma and cryoprecipitate B. Crossmatched platelets and washed RBCs C. Factor IX concentrates and FFP D. Irradiated RBCs, platelets, and granulocytes

D This cancer patient may be immunocompromised from the medication but needs to receive RBCs for anemia; therefore, irradiated RBCs are indicated. Platelets may be needed to control bleeding, and granulocytes may be indicated for short-term control of severe infection. Harr, Robert R. Medical Laboratory Science Review (Page 153). F.A. Davis Company. Kindle Edition.

Which of the following conditions is most likely to cause a falsely high creatinine clearance result? A. The patient uses the midstream void procedure when collecting his or her urine B. The patient adds tap water to the urine container because he or she forgets to save one of the urine samples C. The patient does not empty his or her bladder at the conclusion of the test D. The patient empties his or her bladder at the start of the test and adds the urine to the collection

D Urine in the bladder should be eliminated and not saved at the start of the test because it represents urine formed prior to the test period. The other conditions (choices A-C ) will result in falsely low urine creatinine or volume and, therefore, falsely lower clearance results. Error is introduced by incomplete emptying of the bladder when short times are used to measure clearance. A 24-hour timed urine is the specimen of choice. When filtrate flow falls below 2 mL/min, error is introduced because tubular secretion of creatinine occurs. The patient must be kept well hydrated during the test to prevent this. Harr, Robert R. Medical Laboratory Science Review (Page 239). F.A. Davis Company. Kindle Edition.

Which of the following is a key characteristic of the thick blood film? A. The ability to see the parasite within the RBCs B. The ability to identify the parasites to the species level C. The examination of less blood than the thin blood film D. The necessity to lake the RBCs during or prior to staining

D With the thick blood film, there is more blood per slide than on the thin film, resulting in greater sensitivity. It is difficult to identify the parasite to the species level from the thick blood film. The RBCs are "laked" while drying or during staining, making it impossible to observe the parasites within the RBCs. Harr, Robert R. Medical Laboratory Science Review (Page 476). F.A. Davis Company. Kindle Edition.

Given the Wiener and Fisher-Race nomenclatures shown below, all of the following offsprings are possible from a mother who is R0R1 and a father who is R1r EXCEPT? Wiener Fisher-Race R0 Dce R1 DCe R2 DcE Rz DCE r dce r' dCe r" dcE ry dCE DcE/DcE DCe/DCe DCe/dce Dce/dce

DcE/DcE It is necessary to convert Wiener system shorthand nomenclature to Fisher-Race nomenclature in order to make this determination. The mother's Fisher-Race genotype for Wiener R0R1 would be Dce/DCe. The father's Fisher-Race genotype for Wiener R1r would be DCe/dce. The baby's Fisher-Race genotype for Wiener cannot be R2R2, (DcE/DcE) because neither parent has the rh (E) antigen. The child could be DCe/DCe if he/she receives DCe from the mother and DCe from the father. It is also possible that the child is DCe/dce if he/she receives DCe from the mother and dce from the father. Lastly, it is possible that the child is Dce/dce receiving Dce from the mother and dce from the father. Question Difficulty: Level 7

Which of the following is NOT a way hemoglobinopathies can be caused? Deletion of a globin chain. Substitution of amino acids in a globin chain. Deletion of an amino acid in a globin chain. Addition of an amino acid in a globin chain.

Deletion of a globin chain. Hemoglobinopathies are not caused by deletion of a globin chain. Partial and complete deletions of globin chains lead to thalassemia. Substitution of amino acids in a globin chain is the most common cause of hemoglobinopathies. Deletion or addition of an amino acid in a globin chain, or fusion of globin chains will also cause hemoglobinopathies. Question Difficulty: Level 8

Motility is a key initial assessment in the presumptive identification of the nonfermentative gram negative bacilli. All of the following organisms are motile EXCEPT? Burkholderia cepacia Alcaligenes faecalis Pseudomonas aeruginosa Elizabethkingia meningoseptica

Elizabethkingia meningoseptica Elizabethkingia species is the only non-motile organism listed for this question. Burkholderia cepacia is incorrect as all members of the genus Burkholderia are motile via polar flagella. Alcaligenes faecalis is incorrect as all members of the genus Alcaligenes are motile via peritrichous flagella. Pseudomonas aeruginosa is incorrect because this species is motile by monotrichous or single flagellum. Question Difficulty: Level 8

Which one of these Gram-positive species has a high incidence of vancomycin-resistance? Aerococcus species Enterococcus faecium Group D streptococci Streptococcus pyogenes

Enterococcus faecium Vancomycin-resistance in Enterococcus faecium is close to 90% in blood cultures in the U.S. In addition to Enterococcus faecium, E. faecalis is also isolated in nosocomial infections such as UTI or bacteremia. Leuconostoc and Pediococcus are other Gram-positive cocci that demonstrate resistance to vancomycin. Aerococcus species, Group D streptococci, and Streptococcus pyogenes are usually susceptible to vancomycin. Aerococcus is an opportunistic pathogen causing infection similar to other gram-positive cocci. Group D streptococci are part of the viridans group found as normal flora, but may cause infections such as bacteremia and endocarditis. Streptococcus pyogenes is found as normal flora existing on skin and in the oropharynx, but may cause serious infections such as pharyngitis, necrotizing fasciitis, TSS, and rheumatic fever. Question Difficulty: Level 8

All of the following are indicators of sepsis, EXCEPT? Erythrocytosis Increased heart rate Leukocytosis Increased body temperature

Erythrocytosis Sepsis results in an immune response by the body. This response includes increasing body temperature and leukocytes in order to help fight off the infection, and increased heart rate in order to get more blood and oxygen to the tissues. Erythrocytosis is not part of the immune response. Question Difficulty: Level 9

In which of the following situations would a bone marrow aspirate and biopsy be MOST LIKELY recommended to aid in diagnosis? Primary evaluation of a hypochromic/microcytic anemia Routine screening for hematologic complications Part of bone density screening Evaluation of unexplained cytopenias

Evaluation of unexplained cytopenias A decrease in leukocytes, erythrocytes, or thrombocytes may be indicative of hematologic disorders such as leukemia, myelodysplastic or myeloproliferative syndromes, aplastic anemia, or other neoplasms that will be identified through the evaluation of a bone marrow evaluation. A bone marrow evaluation is an invasive and painful procedure with risks and would not be recommended as part of a primary evaluation for hypochromic/microcytic anemia. Instead, iron studies would be the first course of action. A bone marrow evaluation is an invasive and painful procedure with risks and would not be recommended as part of a routine hematologic workup. If erythrocytic, leukocytic, and thrombocytic changes are unable to be explained through other means, a bone marrow procedure may be ordered. Bone density is not diagnosed through bone marrow biopsies or aspirates. Question Difficulty: Level 8

Salmonella typhi Salmonella typhi is the correct answer because the patch of black seen in the KIA (Kligler Iron Agar) tube to the right in the photograph represents a small amount of H2S production confined to the angle between the slant and the deep. This small amount of H2S gas production is characteristic of Salmonella typhi. Shigella sonnei is incorrect because the organism does not produce H2S. Pseudomonas aeruginosa is incorrect because this organism is a nonfermenter; therefore, the glucose will not be fermented resulting in an alkaline (red) deep. Pseudomonas aeruginosa also lacks the ability to produce H2S. Shewanella putrifaciens is incorrect because this organism is a nonfermenter; however, it does have the capability to produce H2S. Shewanella putrifaciens will produce an alkaline (red) deep, due to it being a nonfermenter. Question Difficulty: Level 5

Examine the KIA tube on the right in the image provided and determine which of the following organisms produces the biochemical reaction seen. Shigella sonnei Pseudomonas aeruginosa Shewanella putrifaciens Salmonella typhi

B A trend is characterized by six consecutive decreasing or increasing control results. The value for both controls becomes progressively higher from day 4 to day 9. Trends are caused by changes to the test system that increase over time, such as deterioration of reagents or calibrators, progressive changes in temperature, evaporation, light exposure, and bacterial contamination. A trend is a type of SE because all results are affected. Conversely, RE affects some results (but not others) in an unpredictable manner. Control rules affected by RE are 13s and R4s . Harr, Robert R. Medical Laboratory Science Review (Page 230). F.A. Davis Company. Kindle Edition.

Examine the Levy-Jennings chart at the bottom and identify the QC problem that occurred during the first half of the month. A. Shift B. Trend C. Random error D. Kurtosis

Thermostable endonuclease The colony morphology as presented in this photograph and the source of infection suggests a Staphylococcus species. Although the thermostable endonuclease test is helpful in identifying Staphylococcus aureus, it is not a direct or immediate test. A positive modified oxidase reaction, using a filter paper disk impregnated with the indicator and dimethyl sulfoxide would provide an immediate means for ruling out Micrococcus species. A rapid positive direct catalase test would support the identification of Staphylococcus species and the slide coagulase test would indicate whether the isolate was coagulase positive or negative. Question Difficulty: Level 4

Examine this photo of a 5% sheep blood agar plate from a wound culture workup. All of the following direct tests would be helpful in making an immediate presumptive identification of the organism growing on the plate EXCEPT: Modified oxidase (DMSO) Catalase Thermostable endonuclease Slide coagulase

Nucleated red cells Not normally seen in the peripheral blood of adults, nucleated RBCs (nRBCs) are often seen in the blood of newborns. A nRBC contains a round nucleus, no nucleoli, condensed chromatin, and a pink cytoplasm. Neutrophils are the most numerous granulocytic white blood cells. The neutrophils' cytoplasm stains pink, with blue/lavender granules, and they have 2-5 lobes to their nucleus which stain dark blue/purple. Lymphocytes are nongranular white cells with a large dark staining nucleus and very little cytoplasm which stains light blue. They are the smallest white cells by size and typically second most numerous after neutrophils. A metamyelocyte has an indented nucleus (<50%), clumpy chromatin, and the cytoplasm contains predominately secondary granules. Question Difficulty: Level 1

Found frequently in a newborn's blood, the cells indicated in this illustration are: Neutrophils Small lymphocytes Metamyelocytes Nucleated red cells

Regarding hemoglobin synthesis, which of the following constitutes the alpha globin chain coding? Two gene loci; one each on chromosome 11. Four gene loci; two each on chromosome 11. Two gene loci; one each on chromosome 16. Four gene loci; two each on chromosome 16.

Four gene loci; two each on chromosome 16. Humans need four gene loci that code for the alpha hemoglobin chain, in order to make their full component of normal hemoglobins. Two alpha chain gene loci are found on each chromosome 16. Beta globin gene (and other beta-like genes) are coded on chromosome 11. Question Difficulty: Level 7

A normal hemoglobin molecule is comprised of the following: Ferrous iron and four globin chains Four heme and four globin chains Four heme and one globin chains One heme and four globin chains

Four heme and four globin chains A normal hemoglobin molecule consists of a tetramer, of four heme and four globin chains, with a molecular weight of 64,500 daltons. Each of the four units can bind a molecule of oxygen for transport to the body's tissues. In the image shown below, there are four monomers (2 red globin chains and 2 blue globin chains) which form the entire hemoglobin tetramer structure. The green portions represent the 4 heme groups. Question Difficulty: Level 4

Neisseria gonorrhoeae Neisseria species are characterized by gram negative diplococci. This image is from a case of Neisseria gonorrhoeae urethritis, illustrating the characteristic intracellular location of the bacterial cells in neutrophils. Escherichia coli is a gram negative bacillus. Neisseria meningitidis is a gram negative diplococci but more likely seen in CSF as a cause of bacterial meningitis. Staphylococcus aureus are gram positive cocci found in irregular clusters. Question Difficulty: Level 8

From the list of organisms below, identify the most likely species based on this image of a gram stain from a male urethral swab. Escherichia coli Neisseria gonorrhoeae Neisseria meningitidis Staphylococcus aureus

What blood group are the RBC screening cells for antibody screens? Group O Group A Group B Group AB

Group O Antibody screening cells are group O reagent red cells that are used to screen for blood group antibodies other than the ABO antibodies. The 2-cell screening cells are O positive. The 3-cell screening cells have one as an O negative. Group A blood cells could not be used for looking for unusual antibodies since they would react with people who have anti-A in their blood (group O and group B individuals would have positive results). Group B blood cells could not be used for looking for unusual antibodies since they would react with people who have anti-B in their blood (group O and group A individuals would have positive results). Group AB blood cells could not be used for looking for unusual antibodies since they would react with people who have anti-A and/or anti-B in their blood (group O, group A and group B individuals would have positive results). Question Difficulty: Level 7

An alpha thalassemia patient is diagnosed as having three of their four genes deleted which code for alpha hemoglobin chains. Which one of the following types of hemoglobin is abnormal and would be found in such a patient? Hb A Hb S Hb F Hb H

Hb H Hemoglobin H is composed of tetrads of beta globin chains instead of the normal two alpha and two beta globin chains. This is because a patient with three inactive alpha genes forms very few alpha chains which normally combine with the beta chains. Hemoglobin H is quite unstable and also has a very high affinity for oxygen. This condition is often known as Hemoglobin H disease. Hemoglobin A is composed of two alpha chains and two beta chains, and is the major adult hemoglobin in unaffected people. A patient with Hemoglobin H disease can only sythesize small amounts of Hb A. Hemoglobin S is a mutated beta chain found in Sickle Cell disease, a completely different inherited disease. It is not found in alpha thalassemia patients unless they inherit that gene as well. Hemoglobin F is composed of two alpha chains and two gamma chains, and is the normal hemoglobin made in fetal life. Patients with Hemoglobin H disease (three deleted alpha genes) are also not able to synthesis much Hb F. Question Difficulty: Level 8

A culture was performed on a stool sample. After growth was obtained on the blood agar plate, the gram stain showed curved gram negative rods. The oxidase, catalase, and urease were positive. What is the most likely bacterial identification? Helicobacter pylori Campylobacter concisus Helicobacter cinaedi Arcobacter spp.

Helicobacter pylori Identification methods for curved gram negative rods will include (in this order) oxidase, catalase, and urease. Helicobacter pylori will have the gram stain showing curved gram negative rods. It will have positive results for oxidase, catalase, and urease. Campylobacter concisus will have the gram stain showing curved gram negative rods. It will have positive results for oxidase along with a negative catalase result. Helicobacter cinaedi will have the gram stain showing curved gram negative rods. It will have positive results for oxidase and catalase along with a negative urease test. Arcobacter spp. will have the gram stain showing curved gram negative rods. It will have positive results for oxidase and catalase along with a negative urease test. Question Difficulty: Level 7

Streptococcus agalactiae Streptococcus agalactiae (group B beta-hemolytic streptococcus) is unique among the streptococci (except for occasional strains of Group G streptococci) in its ability to hydrolyze hippurate to benzoic acid and glycine. The positive blue reaction seen in the left tube in the photograph illustrates the presence of glycine, after the addition of ninhydrin reagent. Streptococcus pyogenes is a beta-hemolytic streptococcus that is not capable of hydrolyzing hippurate which differentiates it from Streptococcus agalactiae. Streptococcus pneumoniae is alpha-hemolytic which differentiates it from Streptococcus agalactiae. Hippurate hydrolysis would not be performed on this species as it is not beta-hemolytic. Streptococcus dysgalactiae subsp. equisimilis may demonstrate beta-hemolysis but it is not capable of hydrolyzing hippurate which differentiates it from Streptococcus agalactiae. Question Difficulty: Level 5

Hippurate hydrolysis is an important characteristic in the definitive laboratory identification of the beta-hemolytic streptococci. The positive ninhydrin reaction, seen in the left tube in the photograph, is produced by: Streptococcus agalactiae Streptococcus pyogenes Streptococcus pneumoniae Streptococcus dysgalactiae subsp. equisimilis

Large, one-celled, smooth-to-tuberculate macroconidia, and smooth or echinulate microconidia are typical of mycelial phase growth of which organism? Blastomyces dermatitidis Coccidioides immitis Histoplasma capsulatum Paracoccidioides brasiliensis

Histoplasma capsulatum Histoplasma capsulatum characteristically shows large, one-celled, smooth-to-tuberculate macroconidia, and smooth or echinulate microconidia. H. capsulatum is a dimorphic fungus which is known to cause histoplasmosis, a lung disease. H. capsulatum can grow in soil and material contaminated with bat or bird droppings. Spores are introduced into the air when contaminated soil is moved/displaced. When spores produced by this fungus are breathed in, the pathogen grows in the lungs as a yeast. Blastomyces dermatitidis is the agent of blastomycosis. In the mycelial phase, the organism produces septate, delicate hyphae with single, pyriform conidia on short to long conidiophores, which resemble lollipops. The mycelial phase of Coccidioides immitis shows small, septate hyphae with right angle branching and racquet forms that develop into rectangular or barrel-shaped arthroconidia. The arthroconidia stain darkly with lactophenol cotton blue and alternate with clear, nonviable disjunctor cells. The mycelial phase of Paracoccidioides brasiliensis shows septate hyphae with small pyriform or globose conidia found on the sides of the hyphae or on short conidiophores. There may also be many chlamydoconidia. Question Difficulty: Level 7

Which of the following casts might be found in the urine of a healthy individual after strenuous exercise? Epithelial cell casts and granular casts Hyaline casts and granular casts Granular casts waxy casts Waxy casts and hyaline casts

Hyaline casts and granular casts Hyaline and/or granular casts may be seen in healthy individuals for a short time period after strenuous exercise. Hyaline casts are seen in even the mildest cases of renal disease and are not particulary associated with any specific disease. Granular casts however, almost always indicate significant renal disease except after strenuous exercise. Question Difficulty: Level 7

Nephrotic syndrome is associated with all of the following clinical findings, except: Increased proteinuria Decreased serum albumin Hyperproteinemia Edema

Hyperproteinemia In nephrotic syndrome, increased proteinuria, decreased serum albumin, and edema are all expected findings. Nephrotic syndrome develops when the kidney glomeruli are damaged, which allows proteins in the blood, especially albumin, to leak into the urine. This causes an increased excretion of protein, or proteinuria. Hyperproteinemia is not associated with patient's suffering from nephrotic syndrome, as hyperproteinemia translates to increased serum protein levels. The opposite is true in cases of nephrotic syndrome. Question Difficulty: Level 7

Entamoeba gingivalis trophozoite Entamoeba gingivalis resembles Entamoeba histolytica both in size and in nuclear characteristics. Entamoeba gingivalis may contain numerous cytoplasmic inclusions such as red blood cells, white blood cells, and bacteria. Question Difficulty: Level 3

I reside in the mouth where I measure approximately 17 micro meters. Entamoeba coli trophozoite Entamoeba gingivalis trophozoite Acanthamoeba species trophozoite Trichomonas vaginalis trophozoite

Which of the following antigen groups is closely related to the ABO antigens on the red cell membrane? Rh Kell I, i Duffy

I, i The I and i antigens exist on the precursor A, B, and H oligosaccharide chains at a position closer to the red cell membrane. The I antigen is associated with branched chains, and the i antigen is associated with linear chains. The products of RH genes are nonglycosylated proteins. This means no carbohydrates are attached to the protein. Rh antigens reside on transmembrane proteins are an integral part of the RBC membrane. Kell blood group antigens are found only on red blood cells. They have not been found on platelets or on lymphocytes, granulocytes, or monocytes. The Duffy antigens (Fya and Fyb) have been identified on fetal red blood cells as early as 6 weeks gestational age. The antigens have not been found on platelets, lymphocytes, monocytes, or granulocytes, but they have been identified in other body tissues. Question Difficulty: Level 7

Promyelocyte The cell in this image is a promyelocyte. The promyelocyte varies in size from 15 to 21 µm with a large nucleus. The nucleus to cytoplasmic (N:C) ratio is high (3:1). Several nucleoli may be present in the nucleus, which stains purple to dark blue. The cytoplasm is basophilic and similar to that of a myeloblast but contains prominent, reddish-purple primary granules (usually more than 20). These primary granules are also call azurophilic granules or nonspecific granules. Myeloblasts vary in size from 14 to 20 µm and have a high N:C ratio (4:1). Myeloblasts sometimes contain primary granules, but if they do, there are less than 20. Blasts without granules are referred to as Type I blasts while blasts with up to 20 primary granules are called Type II blasts. Nucleoli are prominent in the nucleus. Myelocytes vary in size from 12 to 18 µm with a N:C ratio of 2:1. Nucleoli are usually not visible and primary granules have either almost disappeared or are not visible. Secondary granules are becoming predominant in the myelocyte as it matures. Metamyelocytes range in size from 10 to 15 µm. The nucleus has a kidney-bean shape (indentation has begun) with no visible nucleoli. The indentation is said to be less than 50% of the diameter of a hypothetical round nucleus. There are many secondary granules in this stage of development. Question Difficulty: Level 7

Identify the cell in this image: Myeloblast Promyelocyte Myelocyte Metamyelocyte

Eosinophil Eosinophils have characteristic large prominent orange/pink granules in their cytoplasm. The nucleus generally is segmented. Monocytes have blue staining cytoplasm with no or few tiny granules. Their nuclei are unsegmented, though often uneven or convoluted. Basophils have very dark blue/purple/black staining granules in their cytoplasm, often obscuring the nucleus. A neutrophil has smaller, slightly bluish/pinkish staining granules in their cytoplasm. A mature neutrophil has a segmented nucleus. Question Difficulty: Level 1

Identify the cell indicated by the arrow. Eosinophil Monocyte Basophil Neutrophil

Ammonium biurate crystal Ammonium biurate crystals appear as yellow to brown spherical bodies with long irregular spicules, known as "thorn apples". They can occasionally be identified in the alkaline urine of healthy patients, but can also be associated with specimens which are old or not stored properly. Cholesterol crystals are found in acid urine and resemble colorless notched plates. Triple phosphate crystals are found in alkaline urine and resemble colorless "coffin lids". Amorphous urates are found in acid urine and look like brick color or yellow/brown dust. Question Difficulty: Level 2

Identify the crystal indicated by the arrow in this alkaline urine: Cholesterol crystal Triple phosphate crystal Amorphous urate crystal Ammonium biurate crystal

Blast cells The correct answer here is blasts. Many of the cells in this image are blasts; lymphoblasts to be exact. This smear should be sent for review and the clinician should be notified. The presence of blasts of any type in the cerebrospinal fluid is always abnormal. Atypical lymphocytes would also display nucleoli, but would have extended cytoplasmic walls that are typically indented from surrounding RBCs. Basophils typically present within the blood during an allergic event. Basophils are also the least common of all granulocytes. Their large granules stain a dark blue-purple color. Monocytes are typically three to four times the size of RBCs with an irregular cytoplasm shape. Monocytes can contain vacuoles. No nucleoli appear within the cytoplasm as seen in blasts and atypical lymphocytes. Question Difficulty: Level 6

Identify the important blood cells displayed in this cerebrospinal fluid sample. Atypical lymphocytes Basophils Monocytes Blast cells

Multinucleate histiocyte This multinucleate giant cell is a histiocyte. Histiocytes are also referred to as tissue macrophages. They are widely distributed throughout the body. Histiocytes can proliferate in tissues and increase the number of cells at the site of inflammation. Question Difficulty: Level 5

Identify the large multinucleated cell found in this cerebrospinal fluid cytospin field. Mesothelial cell Tumor cell Multinucleate histiocyte Macrophage

Synovial lining cells The large foamy cells in the joint fluid are synovial lining cells. Synovial lining cells have a similar appearance to mesothelial cells with a slightly denser cytoplasm. Mesothelial cells do not show up in synovial spaces, only serous spaces. Question Difficulty: Level 5

Identify the large, foamy cells in the joint fluid image shown to the right. Macrophage Bronchial lining cells Tumor clump Synovial lining cells

Barr body The neutrophil in this image has a tiny projection off of one of its lobes called a Barr body. A Barr body is a structure composed of condensed X chromosome that is found in nondividing nuclei of female mammals. Hypersegmentation refers to an increase in the number of lobes (> 5) of the neutrophilic nucleus where hyposegmentation is a decrease in lobes. Karyorrhexis refers to disintegration of the nucleus which creates chromatin fragments and not projections. Question Difficulty: Level 5

Identify the neutrophil nuclear projection in this image. Barr body Hypersegmentation Hyposegmentation Karyorrhexis

Basophil Basophils have a lobulated nucleus with a clumped chromatin pattern that is often obscured by its characteristic large prominent dark purple-blue granules. Furthermore the granules are water soluble and some often dissolve giving a red-purple wash over the entire cell. Myelocytes have a rounded nucleus and the beginning of more significant chromatin clumping. Early stages have some primary or non-specific granules present. These are dark purple-blue, but are not as large as basophil granules. Secondary or specific granule production has begun. These granules are smaller, lighter and more lavender in color. As the myelocyte enters the end of this stage, there are fewer primary granules and many more secondary granules present. Neutrophils have a lobulated nucleus with a clumped chromatin pattern. The granules present are mostly secondary or specific granules that are fine and lavender in color. Eosinophils usually have a bi-lobed nucleus with a clumped chromatin pattern. Their cytoplasm is full of large orange-red secondary or specific granules. Question Difficulty: Level 1

Identify the white blood cell seen in this illustration: Myelocyte Neutrophil Eosinophil Basophil

Alpha naphthol with diacetyl The correct answer is alpha naphthol and diacetyl. The positive Voges Proskauer reaction involves the production of a red color complex in the test medium upon addition of alpha naphthol. Acetoin (dimethyl carbinol) is the product of carbohydrate metabolism by VP-positive bacteria. Alpha naphthol, however, does not react directly with acetoin, rather with diacetyl, the next step in the metabolic pathway of acetoin. Diacetyl is produced by the addition of potassium hydroxide to the test mixture. Thus, potassium hydroxide serves merely as a catalyst, not as a part of the color complex. Acetoin is the next step in the metabolic degradation of pyruvate, neither of which are involved in the final color complex. Question Difficulty: Level 7

Illustrated in the left tube of this photograph is a positive Voges Proskauer reaction (left tube). The red pigment is produced from the reactions of: Alpha naphthol with acetoin (dimethyl carbinol) Alpha naphthol with diacetyl Potassium hydroxide with acetoin (dimethyl carbinol) Pyruvate with acetoin (dimethyl carbinol)

Stemphylium species Stemphylium colony morphology varies and is non-specific, even within the different strains of a given species. The identification of Stemphylium species is determined by the microscopic appearance of the macroconidia and mode of attachment to the conidiophore. Illustrated are small brown-staining muriform (divided into multiple cells by longitudinal and transverse septa) macroconidia, one of which is produced at the tip of a septate conidiophore, the terminus of which is slightly swollen and more darkly pigmented. These are features characteristic of Stemphylium species. Curvularia macroconidia have the distinction of being composed of four or five cells that are separated by transverse septa. The second cell from the terminal end of the conidium continues to grow after the others have matured. This cell becomes enlarged imparting a curved shape to the muriform conidium that has been described as a "boomerang". Ulocladium muriform macrocoonidia are somewhat similar in appearance to those of Stemphylium with the exception that they are born singly from the tips of short, twisted "bent-knee" or geniculate conidiophores. Alternaria macroconidia are also multi-celled, but are large, drumstick in shape, with each macroconidium having a distinctive elongated beak butting against the rounded, blunt end of the next that results in the formation of long chains. Question Difficulty: Level 4

Illustrated in the top photograph is the 3 day growth of a colony on Sabouraud's dextrose (SAB) agar incubated at 35oC. The colony surface is cottony with distinct radial striations. The reverse of the colony shows dark brown to black pigmentation. The bottom photomicrograph illustrates the distinctive conidial formation. With these observations, select the correct identification of this fungus. Curvularia species Ulocladium species Alternaria species Stemphylium species

Mycobacterium kansasii Mycobacterium kansasii is the correct response. The conversion from gray-white to distinctly yellow pigmented colonies upon exposure to ambient light is characteristic of one of the photochromogens. The observation of rod-shaped acid fast bacilli with cross banding is characteristic of this presumptive identification, supported by the selective positive reactions produced by several of the biochemicals used in the identification of acid-fast bacilli -- nitrate reduction, Tween 80 hydrolysis, catalase, and urease. Mycobacterium scrofulaceum is a scoto-chromogenic acid-fast bacilli, where yellow pigmentation of colonies would be observed both prior to and after exposure to ambient light. Acid-fast bacilli are observed in acid fast stains, but are non-selective. The difference between this species and M. kansasii is that this species has negative biochemical reactions for nitrate reduction and Tween 80 hydrolysis. Mycobacterium avium-intracellulare is a nonphotochromogenic Mycobacteria. Colonies on 7H10 agar vary from smooth to wrinkled and no pigment is produced with or without light. Long, slender acid-fast bacilli with faint cross barring are observed in acid fast stains. The biochemicals listed as being positive for M. kansasii are negative. Mycobacterium fortuitum is a rapid grower and colonies are never pigmented, even after exposure to light. Rapid growth in culture occurs within 3 - 5 days and is an additional distinguishing characteristic from M. kansasii. Biochemical reactions listed for M. kansasii are also positive for M. fortuitum and are not distinctive. Question Difficulty: Level 1

Illustrated in this exercise are colonies growing on Middlebrook 7H10 agar before (lower) and after (upper) exposure to light. Colonies are intermediate between smooth and rough depending on the strain. Prior to light exposure, the colonies are gray white. Upon exposure to ambient light, visible yellow pigment production is observed characteristic of one of the "photochromogens", as illustrated in the top composite colony photograph. The acid-fast stain reveals slender acid fast bacilli with cross banding. Characteristic for this isolate are positive reactions for several biochemical reactions - nitrate reduction, Tween 80 hydrolysis, catalase, and urease. With these observations, select the species name of this isolate. Mycobacterium scrofulaceum Mycobacterium avium-intracellulare Mycobacterium kansasii Mycobacterium fortuitum

Which of the following are indicators of sepsis? Erythrocytosis Increased heart rate Leukocytosis Increased body temperature

Increased heart rate Leukocytosis Increased body temperature Sepsis results in an immune response by the body. This response includes increasing body temperature and leukocytes in order to help fight off the infection, and increased heart rate in order to get more blood and oxygen to the tissues. Erythrocytosis is not part of the immune response. Question Difficulty: Level 9

Which of the following are indicators of sepsis? Erythrocytosis Increased heart rate Leukocytosis Increased body temperature

Increased heart rate Leukocytosis Increased body temperature Sepsis results in an immune response by the body. This response includes increasing body temperature and leukocytes in order to help fight off the infection, and increased heart rate in order to get more blood and oxygen to the tissues. Erythrocytosis is not part of the immune response. Question Difficulty: Level 9

Why is hereditary hemochromatosis (HH) thought to be underdiagnosed? Its early symptoms are nonspecific and vague, and generally do not get serious until later in life. It is an extremely rare disease. It appears shortly after birth, but then symptoms rapidly subside. It is a mild disorder and has no severe implications for one's health.

Its early symptoms are nonspecific and vague, and generally do not get serious until later in life. HH is thought to be underdiagnosed because its early symptoms are vague and nonspecific and there is lack of awareness about HH on the part of patients and physicians. HH is an iron-overloading disorder in which excess amounts of iron are absorbed. Over the course of decades, high iron stores begin to accumulate in various organs of the body leading to liver and other organ damage. Therefore, serious symptoms only start in the later decades in life, and symptoms can be non-specific and vague at first. HH is actually quite common, especially among people of northern European ancestry. In the US, approximately 1 in 8 to 1 in 10 people are carriers, while about 1 in 250 are homozygotes with the disease. As mentioned above, it takes decades for iron to accumulate to the point of causing overt symptoms, so it is not seen at birth. Also, it gets worse as time goes on, not better. Though it might start out as mild, iron stored in organs in high quantities is toxic, and will lead to organ dysfunction, and can eventually even lead to death. Therefore, it does have severe implications. Question Difficulty: Level 7

Which of the following organisms is a lactose fermenter? Morganella morganni Proteus mirabilis Shigella sonnei Klebsiella oxytoca

Klebsiella oxytoca Klebsiella oxytoca produces acid/acid KIA reactions and red to pink colonies on MacConkey agar, indicating the ability to ferment lactose. Morganella morganni, Proteus mirabilis, and Shigella sonnei do not ferment lactose. They appear as Alk/Acid on KIA and as non-pigmented colonies on MacConkey agar. Question Difficulty: Level 7

Which of the following scenarios represents appropriate detection of MRSA by the Kirby Bauer method? Mueller-Hinton agar (MHA); direct colony suspension; 37oC; cefoxitin disk; 36 hour incubation MHA; direct colony suspension; 35oC; oxacillin disk; 18 hour incubation MHA; direct colony suspension; 35oC; cefoxitin disk; 18 hour incubation MHA; direct colony suspension; 35oC; cefoxitin disk; 24 hour incubation

MHA; direct colony suspension; 35oC; cefoxitin disk; 18 hour incubation Mueller-Hinton agar is the standard medium for Kirby Bauer testing on Staphylococcus isolates. The direct colony suspension method, utilizing a 0.5 McFarland standard, should be used to prepare the inoculum. A 16 to 20-hour incubation is required. A 30 µg cefoxitin disk is recommended to detect mecA mediated resistance. Incubation above 35°C may not allow for the detection of resistance. Oxacillin is recommended only for MIC detection with an incubation of at least 24 hours at 35°C, not for disk diffusion testing. Question Difficulty: Level 8

Which Mycobacterium species will have a negative result for niacin, nitrate reduction, Tween hydrolysis (5 days), and iron uptake? Mycobacterium tuberculosis Mycobacterium kansasii Mycobacterium bovis Mycobacterium gordonae

Mycobacterium bovis Mycobacterium bovis will have negative results for niacin, nitrate reduction, Tween hydrolysis (5 days), and iron uptake. Mycobacterium tuberculosis will have positive results for niacin and nitrate reduction and negative results for Tween hydrolysis (5 days) and iron uptake. Mycobacterium kansasii will have a negative result for niacin, positive results for nitrate reduction and Tween hydrolysis (5 days), and a negative result for iron uptake. Mycobacterium gordonae will have negative results for niacin and nitrate reduction and a positive result for Tween hydrolysis (5 days) and will have variable results with iron uptake. Question Difficulty: Level 9

MacConkey agar without crystal violet is a culture medium useful in the presumptive identification of: Mycoplasma pneumoniae Mycobacterium fortuitum Legionella pneumophila Vibrio parahemolyticus

Mycobacterium fortuitum Mycobacterium fortuitum is the correct answer because it has the capability of growing on modified MacConkey agar without crystal violet, in contrast to other Mycobacterium species that do not grow. This media is helpful in the identification of rapidly growing mycobacteria. Mycoplasma pneumoniae is incorrect because the culture medium for the presumptive identification of Mycoplasma pneumoniae is methylene blue-glucose biphasic medium (New York City Medium). Stuart's medium, trypticase soy broth supplemented with 0.5% bovine serum albumin, Mycotrans, and A3B broth are all additional media that can be used for the isolation of Mycoplasma pneumoniae. Legionella pneumophila is incorrect because the preferred media for the isolation of Legionella pneumophila is buffered charcoal yeast extract agar (BCYE). Vibrio parahemolyticus is incorrect because it is best isolated from the medium thiosulfate citrate bile sucrose (TCBS) agar. Question Difficulty: Level 7

All of the following Mycobacterium species will cause tuberculosis, EXCEPT? Mycobacterium bovis Mycobacterium africanum Mycobacterium leprae Mycobacterium microti

Mycobacterium leprae Mycobacterium leprae does not cause tuberculosis. It is associated with two major forms of disease; tuberculoid leprosy and lepromatous leprosy. Along with Mycobacterium tuberculosis, M. bovis, M. africanum, M. microti, M. canetti, M. caprae, and M. pinnipedii can each cause tuberculosis and are members of the tuberculosis species complex. Question Difficulty: Level 9

Staphylococcus epidermidis Staphylococcus epidermidis is the correct response. Colonies are smooth with a white or gray-white color. Microscopic observation of gram stains reveals gram-positive cocci in small loose clusters, often in tetrad formation. The catalase reaction is positive, and the coagulation reaction is negative. A definitive identification requires further testing. Staphylococcus aureus colonies are smooth and may be cream-colored or yellow, but can be microscopically differentiated from both S. epidermidis and Micrococcus sp. by observing gram-positive cocci that form tight grape-like clusters rather than arranging in loose clusters or in tetrads. Confirmation can be made by demonstrating a positive coagulase reaction. Micrococcus luteus colonies are smooth, but often produce distinctly yellow pigment. Tetrad formation of the gram-positive cocci may be observed microscopically in gram stains. The catalase reaction is positive, and the coagulation reaction is negative. Confirmation of M. luteus can be made with further testing, such as positive modified oxidase, and susceptibility to bacitracin ("A disc"). Rothia mucilaginosa colonies are clear to light pink-gray and are distinctly mucoid and adherent to the agar surface. Rothia spp. may resemble gram positive coryneform bacilli, in pairs or short, filamentous chains, but gram positive cocci are observed when grown in broth. A definitive identification requires further testing. Rothia is also indigenous to the oral cavity and may be recovered in cases of dental plaque infections. Question Difficulty: Level 1

Observed on the surface of blood agar are smooth, white, 48-hour-old colonies incubated at 37oC, demonstrating a positive catalase reaction and a negative coagulase reaction. The sample was taken from an intravenous catheter. In the photomicrograph are gram positive cocci distinctly arranged in loose clusters and in tetrad formation. From these observations, select the presumptive identification of this isolate. Staphylococcus aureus Staphylococcus epidermidis Micrococcus luteus Rothia mucilaginosa

Burkholderia cepacia Motility via a polar flagellum is characteristic of the bacterial cells of Pseudomonas species, including the rRNA group II Pseudomallei group, reclassified within the genus Burkholderia. Burkholderia species, including Burkholderia cepacia, have tufts of multitrichous polar flagellae, as shown in the photomicrograph. Colonies of B. cepacia are non-wrinkled and may produce yellow pigment, aiding in identification. Both Alcaligenes faecalis and Bordetella bronchiseptica are motile, but via peritrichous and not polar flagella. Acinetobacter baumannii is non motile and lacks flagellae. Pigment production is not an identifying feature of these species. Question Difficulty: Level 7

Of the Gram-negative bacilli listed below, which is motile with polar tufts of flagella and can produce yellow pigment? Alcaligenes faecalis Bordetella bronchiseptica Burkholderia cepacia Acinetobacter baumannii

Anti-Fya, -C The correct answer is anti-Fya and anti-C. This is a fairly basic panel, but it involves further thought. First, it asks you to determine which antibodies are not ruled out. Upon completing the rule-outs on screen cell #3, one must then evaluate those remaining antibodies that have not been ruled out for clinical significance. Eliminate choice A immediately, because D is ruled out based on cell #3 at the clinically significant phase of 37°C. Next, it asks you to assess which of the antibodies that have not been ruled out are clinically significant. Of the remaining choices (B, C, and D), you can immediately rule out choices B and C, because both choices contain antibodies that are not clinically significant (anti-Lub, -Lea). Two antibodies that you are unable to rule out at the clinically significant phase of 37°C are contained in the only remaining answer choice, which is choice D. Anti-Fya and anti-C also happen to be clinically significant, because they are reactive at 37°C and can impact the patient in vivo. Question Difficulty: Level 9

On a quiet evening shift at a small hospital, you encounter a specimen with a positive antibody screen. As per your current laboratory protocol, you check for agglutination at the immediate spin phase of testing; and then again at the antihuman gloubulin (AHG) phase of 37°C. According to your laboratory guidelines, a single homozygous cell may be used to rule out an antibody. Based on the following 3-cell screen performed by tube, which of the following clinically significant antibodies are you unable to rule out? Anti-Fya, -D Anti-Lub, -Lea, -Fya, -C Anti-Lea, -Fya, -C Anti-Fya, -C

Patient 3 Alpha thalassemia is a collection of conditions where there is a decrease or absence in the production of the two alpha chains needed for the formation of normal hemoglobin A, A2 and F. Instead, patients will produce varying amounts of hemoglobin H which is made with four beta chains. Patient 3 shows a significantly decreased amount of hemoglobin A with a distinct visible band of hemoglobin H. The presence of hemoglobin H is characteristic for alpha thalassemia. Note: In hemoglobin electrophoresis using alkaline gel, hemoglobin patterns will fall, from left to right, as Hemoglobin A2/C, S/D, F, A, H (also called Barts). Patient 1 is normal with significant amount of hemoglobin A and a faint band for hemoglobin A2. Patients with alpha thalassemia would have markedly decreased hemoglobin A. Patient 2 has visible bands in both hemoglobin A and C regions. Patients with alpha thalassemia would not be producing significant amounts of hemoglobin A and C. Patient 4 shows bands for hemoglobin A2, hemoglobin S and hemoglobin A. Patients with alpha thalassemia would not be producing significant amounts of hemoglobin A and C. Question Difficulty: Level 6

On this alkaline electrophoresis gel, which patient most likely has alpha thalassemia? Lanes 5 and 6 represent controls. Patient 1 Patient 2 Patient 3 Patient 4

What is the nucleated cell present in the following image? Osteoblast Megakaryocyte Osteoclast Macrophage

Osteoblast Osteoblasts are large cells (up to 30 µm). They resemble plasma cells, however, the perinuclear halo is detached from the nucleus and found in the cytoplasm. The nucleus has a finer chromatin patters. The cytoplasm is less basophilic than plasma cells. Osteoblasts are typically found in groups. They are commonly seen in children and metabolic bone diseases. Mature megakaryocytes are large cells up to 100 µm in diameter. These cells have an abundance of acidophilic, granular cytoplasm. The nucleus is large and multi-lobulated with no visible nucleoli. Osteoclasts are larger than osteoblasts (up to 100 µm). Osteoclasts can be multinucleated with discrete nuclei and the cytoplasm can be acidophilic or basophilic. They can resemble megakaryocytes. However, the megakaryocyte has a single, large multi-lobulated nucleus. Macrophages are monocytes that have entered the tissues. Macrophages can range from 15-80 µm. The nucleus is round with a reticular appearance and nucleoli are present. The blue-gray cytoplasm has irregular edges and vacuoles. Question Difficulty: Level 9

All of the following are required to be in a machine-readable format on a blood component label, EXCEPT: ABO & Rh of the donor Product code Collection facility Outdate

Outdate The correct answer is outdate. The outdate may be handwritten, but must be legible. 21 CFR 606.121 requires this information be machine-readable: A unique collection facility identifier Lot number relating to the donor Product code ABO and Rh of the donor Question Difficulty: Level 7

Patient A has a positive solubility test. Patient A is a positive result, indicated by a turbid solution. A negative result (patient B) is obtained when lines are visible through the solution. Most hemoglobins are soluble in a high-molarity phosphate buffer; hemoglobin S is not. However, this test is considered a screening test and cannot distinguish between sickle cell disease (Hb SS) and sickle cell trait (Hb SA). The alkaline electrophoresis result should be reviewed to determine whether the sickling hemoglobin is homozygous or heterozygous. Hemoglobins D and G migrate with hemoglobin S on the alkaline hemoglobin electrophoresis. Further testing may also be needed to confirm other hemoglobins in Patient B. Question Difficulty: Level 3

Patient A and patient B both had hemoglobin migrating in the S position on an alkaline hemoglobin electrophoresis. Which of the following interpretations is appropriate for the sodium metabisulfite tests shown here? Patient A has a positive solubility test. Patient B has a positive solubility test. Patient B has a inconclusive solubility test, the technologist should repeat the test. Patient A has a inconclusive solubility test, the technologist should repeat the test.

Plasmodium malariae Plasmodium malariae is the correct selection. The infected erythrocytes are not enlarged. Characteristic in the development of the trophozoite is the bridge-like extension between the outer erythrocyte membrane and ultimately the formation of a schizont within which the individual merozoite segments are less than 12, forming a rosette around malarial pigment. Plasmodium vivax is an incorrect response. The developing trophozoites of P. vivax remain spherical but occupy more space within the infected erythrocyte by producing a cytoplasm that is flowing or ameboid in outline. The infected erythrocytes are enlarged. Also distinctive is the development of schizonts that have greater than 12 merozoite segments. The erythrocytes are enlarged with a pale cytoplasm within which is a dispersion of Schüffner dots. Plasmodium falciparum is an incorrect response. The developing trophozoites of P. falciparum remain in the small circular form and often are plastered on the inner membrane of the infected erythrocytes in an "appliqué" form. Schüffner dots are not seen. Developing merozoite ring forms or schizonts are rarely observed in peripheral blood smears. Plasmodium ovale is an incorrect response. Developing trophozoites of P. ovale are spherical and do not occupy extended space within the infected erythrocytes. The erythrocytes are distinctly enlarged and oval in outline as the species name suggests, with small aggregates of early Schüffner dots. Schizonts commonly contain abundant malarial pigment and have only 8 segments. Question Difficulty: Level 1

Patients with a diagnosis of malaria who have fever spikes less frequently, spanning three or four days, are said to have "quartan malaria". Illustrated in the high power upper photomicrograph is a stained peripheral blood smear. Note the infected red blood cell that contains a developing trophozoite that distinctively "bridge" between the opposite erythrocyte membranes. The lower photomicrograph illustrates the schizont stage of development in which segments are arranged as a rosette around a central aggregate of malarial pigment. Which of the Plasmodium species is represented in this scenario? Plasmodium vivax Plasmodium falciparum Plasmodium malariae Plasmodium ovale

Rhodotorula mucilaginosa Rhodotorula mucilaginosa is the correct response. In most mycology laboratory practices, the pink-red pigmentation of the yeast colonies would provide a visual presumptive identification. Most commonly the demonstration of a rapid positive spot urease reaction would be used to confirm the identification rather than setting up the streaking of cornmeal agar. Microscopically small oval yeast cells are observed in mounts, some producing an elongated bud. Catheter-related infections, particularly peritonitis in patients receiving peritoneal dialysis, is one of the more common opportunistic infections caused by this yeast. Malassezia furfur is incorrect. Malassezia furfur reveals both hyphal elements and small 3 - 5 um in diameter budding yeast cells, with a distinct dark staining collarette at the margin between the mother and daughter cell, a microscopic appearance referred to as "spaghetti and meatballs". Aureobasidium pullulans is incorrect. Aureobasidium pullulans are characterized as "black yeasts". Microscopically, this species will produce dark-staining, non-budding arthroconidia in chains, with small single celled, non-encapsulated microconidia seen in the background. Saccharomyces cerevisiae is incorrect. Saccharomyces cerevisiae colonies are gray-white in color devoid of the pink-red pigment. Distinctive is the microscopic appearance of small spherical ascospores that stain positive in acid-fast preparations. Question Difficulty: Level 5

Pink-pigmented, smooth, 48 hour yeast colonies growing on Sabouraud's dextrose have a characteristic appearance leading to a presumptive identification. This environmental yeast may be recovered from cultures obtained from shower curtains, bathtubs, and tooth brushes. The isolate presented here was recovered from peritoneal fluid of a 45 year old woman receiving peritoneal dialysis. Illustrated in the bottom photomicrograph is growth on cornmeal agar revealing loose clusters of yeast cells with the absence of pseudohyphae. Select the identification of this yeast. Malassezia furfur Rhodotorula mucilaginosa Aureobasidium pullulans Saccharomyces cerevisiae

A patient has a history of repeated spontaneous abortion. Coagulation studies reveal an elevated APTT, normal PT, normal platelet function, and normal thrombin time. Schistocytes were seen on the peripheral blood smear. Which test should be performed to determine if the patient has lupus anticoagulant? Factor VIII assay Mixing studies with factor-deficient plasmas Antinuclear antibody test Platelet neutralization test

Platelet neutralization test Platelet neutralization tests are one of the confirmatory tests that can be used to determine if a patient has a circulating lupus antibody, or lupus anticoagulant. The principle in this test involves the use of a freeze-thawed platelet suspension that, when mixed with the patient plasma, will neutralize the anti-phospholipid antibodies (lupus anticoagulant) present and allow for a corrected APTT result upon re-testing. A Factor VIII assay would be abnormal due to the interference of the lupus anticoagulant with the phospholipid in the APTT test that is used to measure Factor VIII activity. Mixing studies are useful as screening tests for lupus anticoagulant and phospholipid antibodies. Mixing studies with factor deficient plasmas and the APTT test would all be abnormal due to the interference of the lupus anticoagulant with the phospholipid in the APTT test that is used to perform the mixing studies. A mixing study using the patient's plasma incubated 1:1 with normal plasma would also be abnormal (uncorrected). The antinuclear antibody test is a screening test for autoimmune diseases such as systemic lupus erythematosus (SLE). Although some patients with SLE may have a lupus anticoagulant, not all patients with lupus anticoagulant have SLE. Question Difficulty: Level 8

A nitrate test is performed on a glucose nonfermenter. When the nitrate reagents were added, no color change occurrs. When zinc dust was added, no color develops. How should this test be reported? Positive for nitrite and negative for molecular nitrogen Negative for molecular nitrogen and negative for nitrate production Positive for molecular nitrogen and negative for nitrite production Negative for nitrate and negative for nitrite reduction

Positive for molecular nitrogen and negative for nitrite production Positive for nitrogen gas and negative for nitrite production is the correct answer. This answer choice was correct since the nitrate to nitrite result was negative, and when zinc dust was added, no color developed. This demonstrated that no nitrate is left in the tube to be reduced; therefore, molecular nitrogen must have been produced from the nitrate. Nitrate broth is used to determine the ability of an organism to reduce nitrate (NO3) to nitrite (NO2) using the enzyme nitrate reductase or perform nitrification on nitrate and nitrite to produce molecular nitrogen. Nitrate broth is incubated and reagents containing sulfanilic acid and α-naphthylamine are added. If the organism has reduced nitrate to nitrite, a diazotized sulfanilic acid is produced. This reacts with the α-naphthylamine to form a red-ish compound. Therefore, if the medium turns red after the addition of the nitrate reagents, it is considered a positive result for nitrate reduction. If the medium does not turn red after the addition of the nitrate reagents, powdered zinc is then added. If the tube turns red after the addition of the zinc, it means that unreduced nitrate was present. Therefore, a red color on the second step is a negative result. If the medium does not turn red-ish after the addition of the zinc powder, then the result is positive. If no red color forms, there was no nitrate to reduce. Since there was no nitrite present in the medium, it assumes that denitrification took place and ammonia or molecular nitrogen were formed. Question Difficulty: Level 8

Which of the following viral families contains DNA as its nucleic acid? Paramyxoviridae Rhabdoviridae Poxviridae Orthomyxoviridae

Poxviridae Viruses contain either RNA or DNA, never both, and are classified by the nucleic acid they contain. The RNA and DNA of the virus can then be single stranded (ss) or double stranded (ds) to further classify and identify the virus. The Poxviridae family viruses are the some of the largest viruses and contain dsDNA. Examples of viruses in this family are Variola virus and Monkeypox virus. Paramyxoviridae family are ssRNA viruses. Representative viruses in this family are Parainfluenza viruses, Mumps virus, Measles virus, and Respiratory Syncytial Virus (RSV). The Rhabdoviridae family and are also ssRNA viruses. The most common virus in this family is the Rabies virus. Orthomyxoviridae family viruses are also ssRNA viruses. The most common viruses in this family are the Influenza viruses. Question Difficulty: Level 8

Burkitt Lymphoma The correct answer here is Burkitt lymphoma. Prominent cytoplasmic vacuolation of Burkitt lymphoma cells helps laboratorians identify these cells in a cytospin preparation of body fluids. Hodgkin's lymphoma is identified with classic Reed-Sternberg cells and not cells with vacuoles. Hairy cell leukemia is an uncommon chronic lymphoproliferative disorder of the B-lymphocyte type. Hairy cell Leukemia is named such because of the fine, hair-like irregular cytoplasmic projections that are characteristic of the lymphocytes. Chronic lymphocytic leukemia can be identified with the presence leukocytosis with a markedly increased number of mature lymphocytes and lymphocytosis. Question Difficulty: Level 2

Prominent vacuolation involving the cytoplasm of abnormal lymphoblast-like cells seen in the peritoneal body fluid preparation shown is a distinctive feature of which disease? Hodgkin Lymphoma Burkitt Lymphoma Hairy Cell Leukemia Chronic Lymphocytic Leukemia

Abiotrophia defectiva (formerly Streptococcus defectivus) and Granulicatella adiacens(formerly S. adjacens, then A. adiacens) are the names currently given to two species of what were previously called nutritionally variant streptococci (NVS). What supplement must be added to blood culture medium to recover these organisms in cases of "culture negative endocarditis?" Thiamine Pyridoxyl Sodiumpolyanethol sulfonate (SPS) Synthetic resins

Pyridoxyl The nutritionally deficient streptococci were also termed thiol-requiring or pyridoxal-requiring variants because they require thiol compounds, either cysteine or the active form of vitamin B6 (pyridoxal), for growth. Thiamine is a supplement required for some so-called dwarf strains of staphylococci to grow. SPS is added to blood culture media primarily to prevent clotting of the added blood. Although SPS enhances the recovery of many bacterial species, it is not a specific supplement required for the growth of the nutritionally deficient streptococci. The addition of synthetic resins to blood culture bottles may enhance recovery of bacteria from patients receiving antibiotics; however, again, this is not a specific nutritional supplement for NVS. Question Difficulty: Level 7

Image C = Klebsiella pneumoniae Image C is not an image of Klebsiella pneumoniae on MacConkey agar. K. pneumoniae produces mucoid, pink to red lactose fermenting colonies on MacConkey agar. Image C shows a nonlactose fermenter which is producing a green pyocyanin pigment, characteristic of Pseudomonas aeruginosa. Haemophilus parainfluenzae can synthesize porphyrin from delta amino levulinic acid, as seen by the red fluorescence of the colonies in Image A. The ALA porphyrin test is useful in the differentiation of Haemophilus species; those organisms that are ALA positive possess the enzymes to convert ALA to porphobilinogen and porphyrin to heme and do not require exogenous heme for growth. Legionella dumoffii grows on buffered charcoal yeast extract agar with colonies that fluoresce brightly with UV light (Image B). Aeromonas hydrophila is an active DNAse producer, as shown by the red pigmentation on the DNAse agar seen in Image D. All other species listed are either DNAse negative or do not grow on this medium. Question Difficulty: Level 7

Refer to the images at the right. Image A is delta amino levulinic acid viewed with ultraviolet light Image B is buffered charcoal yeast extract agar viewed with ultraviolet light Image C is MacConkey agar Image D is DNAse agar. Review each of the following names of the bacterial species with the appearance and reactions of the colonies seen on the media listed. Each is a correct match of the species with its appearance on the media EXCEPT: Image A = Haemophilus parainfluenzae Image B = Legionella dumoffii Image C = Klebsiella pneumoniae Image D = Aeromonas hydrophilia

C Although the trend is apparent across QC levels by day 7, the patient results would not be rejected until day 8 when the 41s rule is broken. An advantage to plotting control data is that trends can be identified before results are out of control and patient data must be rejected. In this case, corrective steps should have been implemented by day 7 to avoid the delay and expense associated with having to repeat the analysis of patient samples. Harr, Robert R. Medical Laboratory Science Review (Page 230). F.A. Davis Company. Kindle Edition.

Referring to the Levy-Jennings chart, what is the first day in the month when the run should be rejected and patient results should be repeated? A. Day 6 B. Day 7 C. Day 8 D. Day 9

All of the following factors offer a protective effect, delaying symptoms in persons with hereditary hemochromatosis (HH) EXCEPT? Regular blood donation Pregnancy Regular use of multivitamins with iron Menstruation

Regular use of multivitamins with iron Hemochromatosis is a condition in which the body accumulates excess iron at a higher rare than normal daily loss (about 1 mg/day). Hemochromatosis can be an aquired or hereditary condition and if not kept under control it can cause damage to parenchymal cells in organs such as liver, heart, and pancreas. The treatment of choice is therapeutic phlebotomy or iron chelation therapy. Pregnancy, menstruation, and regular blood donation are thought to offer a protective effect, delaying symptoms in persons with HH, while regular use of multivitamins with iron will most likely speed up the the development of symptoms. Question Difficulty: Level 7

The formula for oxidative/fermentative (OF) culture media, for the determination of glucose oxidizers, differs from carbohydrate fermentation media by each of the following properties except: Relative decrease in the protein concentration Relative increase in the carbohydrate concentration Relative decrease in the agar concentration Relative increase in the salt concentration

Relative increase in the salt concentration The concentration of protein is reduced in OF medium, and the relative amount of carbohydrate is increased. This is done to maximize the production of acid from the increased amounts of carbohydrate and to reduce the amount of alkaline amines produced from the oxidation of the amino acids. The agar concentration is decreased so that any acid produced from the carbohydrate will have free access to the color indicator. The concentration of sodium chloride is equal both in fermentative and OF media. Question Difficulty: Level 8

Gram positive cocci isolated from a catheterized urine culture on a 76-year-old male gave the following reactions: Blood agar- creamy, white, opaque colonies with are not hemolytic Catalase- positive Slide coagulase- negative Tube coagulase- negative Novobiocin- susceptible The next action that the medical laboratory professional should take is to Report the isolate as coagulase negative staphylococcus Report the isolate as Staphylococcus epidermidis Report the isolate as Staphylococcus saprophyticus Perform further testing to speciate the organism

Report the isolate as coagulase negative staphylococcus Report the isolate as coagulase negative staphylococci is the correct answer because this is an isolate from a urine specimen with a coagulase negative Staphylococcus that is susceptible to novobiocin. The isolate cannot be reported as Staphylococcus epidermidis because further testing would be needed to speciate the organism to separate it from the other coagulase negative staphylococci. Staphylococcus saprophyticus is resistant to novobiocin; thus, this is not the correct choice. Further testing is required to speciate coagulase negative staphylococci but only if the specimen is from a sterile body site, not urine. Coagulase negative staphylococci, excluding Staphylococcus saprophyticus, is resident microflora of the urethra. Question Difficulty: Level 7

Which one of these test systems can be used to evaluate the adequacy of fibrinogen in heparinized patients? D-Dimer Reptilase Time Thrombin Time None of the above

Reptilase Time Reptilase time can be performed on blood that contains heparin since it does not interfere with the clotting process in this test. Patients who have qualitative or quantitative fibrinogen disorders are associated with prolonged reptilase time results. D-dimer testing is affected by heparin causing a decrease in sensitivity. Thrombin time is similar to reptilase time testing, but uses thrombin rather than snake venom and therefore is sensitive to the presence of inhibitors such as heparin. Question Difficulty: Level 7

The amplification of an RNA target through Reverse transcription PCR (RT-PCR)to detect HIV requires the following enzyme for the initial synthesis of DNA from the viral RNA template: Transcriptase Reverse transcriptase Taq polymerase Thermocycler

Reverse transcriptase Reverse transcriptase is the enzyme used to synthesize DNA from an RNA viral template. Transcriptase is used to synthesize RNA from DNA viral template. Taq polymerase is an enzyme used for primer extension during the annealing of primers to target sequences in PCR. The thermocycler is an instrument that alters the temperature and allows the denaturing and annealing steps of PCR. Question Difficulty: Level 7

Image B = Moraxella catarrhalis Image B shows gram positive cocci arranged in chains, which is typical of the streptococci. The alpha hemolytic viridans streptococci can be suspected if very long chains of cocci are seen, as illustrated in Image B. Moraxella catarrhalis are gram negative diplococci with adjacent ends flattened, Staphylococcus epidermidis are gram positive cocci that arrange in clusters or in groups of four called tetrads, as seen in Image A. Streptococcus pneumoniae typically appears as lancet-shaped, gram positive diplococci in Gram-stained preparations, as seen in Image C. Enterococcus faecalis produces gram positive cocci in pairs or short chains, as seen in Image D. Question Difficulty: Level 7

Review each matched pair. Each correctly matches the bacterial species with its Gram staining reaction and morphology EXCEPT: Image A = Staphylococcus epidermidis Image B = Moraxella catarrhalis Image C = Streptococcus pneumoniae Image D = Enterococcus faecalis

All of the following organisms are known to be resistant to vancomycin EXCEPT? Staphylococcus aureus Enterococcus faecium Enterococcus faecalis Rhodococcus equii

Rhodococcus equii Rhodococcus equii is the correct answer because Rhodococcus species are susceptible to most antibiotics and can be treated with erythromycin and rifampin, gentamicin, tobramycin, ciprofloxacin, vancomycin, and imipenem. Staphylococcus aureus is incorrect because this species is known to have vancomycin resistance, hence, the species names Vancomycin Intermediate Staphylococcus aureus (VISA) and Vancomycin Resistant Staphylococcus aureus (VRSA). Enterococcus faecium and Enterococcus faecalis are both incorrect because both organisms have an acquired resistance to vancomycin as well other classes of antibiotics. Vancomycin resistance can occur due to alterations in the molecular structure of cell components, which decreases the vancomycin binding allowing cell wall formation to continue. In addition, excess peptidoglycan production can also lead to vancomycin resistance. Question Difficulty: Level 8

What is the MOST likely identification of a pink yeast isolate, recovered from respiratory secretions of a patient with AIDS, that gave the following results? Germ tube - negative Urease - positive Blastospores - positive Arthrospores - negative Rhodotorula spp. Cryptococcus spp. Candida albicans Trichosporon spp. Blastomycosis

Rhodotorula spp. Rhodotorula spp. The genus Rhodotorula includes three species including: Rhodotorula glutinis, Rhodotorula mucilaginosa, and Rhodotorula minuta. Rhodotorula spp. are occasionally isolated as causative agents of opportunistic mycoses in vulnerable hosts, including patients with AIDS. Question Difficulty: Level 7

Which of the following barriers are recommended in microbiology laboratories where manipulation of biosafety level 3 agents (e.g., Mycobacterium tuberculosis) is performed? Manual closing single-door access Positive airflow that moves air out of the laboratory Filtered and recirculated air can enter other lab areas Self-closing double-door access

Self-closing double-door access At biosafety level 3, laboratory manipulations should be performed in a Class I or Class ll BSC. Secondary barriers should include self-closing double-door access and NEGATIVE airflow into the laboratory. Exhausted air must not be recirculated. Air may be high-efficiency particulate air (HEPA) filtered, reconditioned and recirculated within that laboratory area, but never into other laboratory areas. Question Difficulty: Level 8

When evaluating the throughput of a particular method you should consider all of the following except: Calibration requirements Sensitivity of technique Reagent preparation time Calculations required to complete test

Sensitivity of technique When evaluating specimen throughput, on would focus on processes and issues that may affect the number of tests that can be performed per hour. Sensitivity does not directly affect assay time and throughput. Calibration requirements, reagent preparation time, and calculations required to complete a test could all affect the specimen throughput. Question Difficulty: Level 7

All of the following Enterobacteriaceae below are appropriately matched with the characteristic listed, EXCEPT: Escherichia coli - indole positive Citrobacter freundii - H2S positive Serratia marscens - Voges-Proskauer negative Klebsiella pneumoniae - indole negative

Serratia marscens - Voges-Proskauer negative The correct answer is Serratia marscens - Voges-Proskauer negative. S.marscens is Voges-Proskauer positive. It is often implicated as a nosocomial infection. Escherichia coli is indole positive. It is the bacterial species that is most commonly recovered in the clinical laboratories. Citrobacter freundii is H2S positive. It has been implicated as a cause of diarrhea and isolated cases of extra-intestinal infections. Klebsiella pneumoniae is indole negative. It is known to cause severe pneumonia, especially in immunocompromised patients. Question Difficulty: Level 8

Proteus mirabilis The alk/acid, H2S positive reactions (red slant, black butt) seen in the Kligler Iron Agar (KIA) tube, coupled with the strong urease reaction (pink color in both the slant and the butt) in the Christensen urea agar slant can provide a presumptive identification of P. mirabilis. Salmonella species produces H2S but negative for urease reaction. Edwardsiella species produce H2S but negative for urease reaction. Shigella sonnei does not produce H2S and is negative for urease reaction. Question Difficulty: Level 5

Shown in this photograph is a Kligler Iron Agar (KIA) slant (left) and a Christensen's urea agar slant (right) after inoculation with an unknown bacterial species and incubation for 24 hours at 35oC. The reactions shown permit a presumptive identification of: Proteus mirabilis Salmonella typhi Edwardsiella tarda Shigella sonnei

Moraxella catarrhalis Moraxella catarrhalis is the correct response. The big clues in the question were the Gram negative cocci (diplococci) and no growth on MacConkey that ruled out the other organisms in this list. All of the other organisms are Gram negative bacilli or cocobacilli but do grow on MacConkey agar. The colonies growing on chocolate agar are small, initially pinpoint in size after 24 hours incubation, and non-pigmented. Growth on Thayer Martin media is scant or absent, ruling out pathogenic Neisseria species. Small, Gram negative cocci are observed in Gram stains. Cytochrome oxidase, nitrate reduction, and catalase reactions are positive. Acid is not produced from carbohydrates (asaccharolytic). M. catarrhalis is commonly recovered from upper respiratory and ear specimens obtained from patients with otitis media and sinusitis. To confirm the identification, butyrate esterase testing can be performed, which is positive for M. catarrhalis. Burkholderia cepacia colonies are relatively small, entire, convex and smooth, with gray yellow pigmentation. Colonies grow on MacConkey agar and are without pigment characteristic of a non-fermenter. The oxidase and catalase reactions are positive; however, nitrate reduction is negative. Acid is produced oxidatively from most carbohydrates. B. cepacia is often recovered from sputum samples of patients with cystic fibrosis. Alcaligenes faecalis colonies on blood agar are grey pigmented and spreading, with light pigment extending into the adjacent agar. Small, plump, Gram negative coccobacilli are seen on Gram stain. A. faecalis does grow well on MacConkey agar. Acid is not produced from carbohydrates and cytochrome oxidase and catalase reactions are positive. Distinctive is the denitrification of nitrates with the production of gas. Acinetobacter baumannii colonies growing on blood agar are relatively large, white, entire, convex and opaque. Entire, smooth, slightly wrinkled colonies with light pink pigmentation are produced on MacConkey agar. Gram negative coccobacilli are also observed in Gram stains. Oxidase and catalase reactions are negative. A. baumannii is saccharolytic while A. lwoffii is asaccharolytic. Question Difficulty: Level 9

The 48-hour growth of small pinpoint gray-white, smooth colonies on chocolate agar (right plate) are most commonly recovered as normal upper respiratory flora but may cause otitis media and sinusitis. There was no growth on Thayer Martin media (left plate). Growth on MacConkey agar is also absent. Short, plump, Gram negative cocci lying singly and in loose clusters are seen in Gram stain, as illustrated in the lower photomicrograph. This non-fermenter is non-motile, oxidase positive, and does not utilize carbohydrates (assacharolytic). Nitrates are reduced and DNAse is positive. From these observations, select from the multiple choices the presumptive identification of this isolate. Burkholderia cepacia Alcaligenes faecalis Moraxella catarrhalis Acinetobacter baumannii

What are the usual results of the mean corpuscular volume (MCV) and the red cell distribution width (RDW) in alpha thalassemia? Both within normal range The MCV is decreased but the RDW is usually increased The MCV is increased but the RDW is normal Both the MCV and RDW are decreased.

The MCV is decreased but the RDW is usually increased The thalassemias are classified as microcytic anemias, thus these patients have decreased MCV values. The red blood cell distribution width (RDW) increases as the severity of alpha thalassemia increases because of changing MCV as the bone marrow produces smaller cells. In addition, if Hemoglobin H bodies are present, they result in the formation of schistocytes (RBC fragments) that can have an effect on the MCV and RDW. Even if the patient is not anemic, someone with thalassemia typically has at least an MCV below range. The MCV is never increased in thalassemia since there is an insufficient amount of globin produced and the cells are smaller than normal. It is rare to have a decreased RDW in any condition, and particularly not thalassemia. Question Difficulty: Level 9

Helmet cell Helmet cells, also known as keratocytes, take on the morphology of a helmet and are associated with microangiopathic hemolytic anemia. Burr cells, or echinocytes, are RBCs that have evenly spaced, spine-like projections around the membrane. Target cells, or codocytes, are bell shaped RBCs with the appearance of a "bull's eye". Stomatocytes are RBCs that cup to form an oval or slit-like central pallor. Question Difficulty: Level 2

The abnormal RBC shape seen in the center of this illustration is a: Burr cell Target cell Helmet cell Stomatocyte

Iron deficiency anemia The red cells seen here are microcytic and hypochromic, characteristic of iron deficiency anemia. This can be observed due to the small lymphocyte present in the image. Normal red blood cells (80-100 fL) approximate the size of a small lymphocyte nucleus. In this case, many of the red blood cells are smaller than the lymphocyte nucleus; therefore, these are microcytes. The hypochromia is apparent as many red blood cells have an increased central pallor, which under normal conditions, should only span about 1/3 of the red blood cell diameter. Folic acid and vitamin B12 deficiencies usually result in megaloblastic anemias which are macrocytic (RBC's greater than 100 fL). Liver disease is the most common condition associated with macrocytic nonmegaloblastic anemia. Question Difficulty: Level 2

The abnormal RBCs seen in this illustration are indicative of: Folic acid deficiency Vitamin B12 deficiency Chronic liver disease Iron deficiency anemia

Clostridium perfringens Clostridium perfringens is the correct response. An immediate presumptive identification of C. perfringens can be made when colonies growing on blood agar after anaerobic incubation show a double zone of hemolysis. The distinct, large, narrow elongated "box-car" shaped gram positive bacilli seen in gram stains prepared from one of the colonies confirms this identification. Of note also is the production of lecithinase on egg-yolk agar. Immediate reporting of this presumptive identification should be made so that selective antibiotic therapy can be administered for treatment of infections presenting as gas gangrene.. Actinomyces israeli colonies on anaerobic blood agar are entire, gray-white and distinctly sunken centrally when mature, resembling a "molar tooth". Beta hemolysis is not observed. The Gram stain observation is that of slender gram-positive branching filaments instead of bacilli with a "box car" formation. Lecithinase is not produced on egg-yolk agar. Cases of lymphadenitis are more commonly encountered. Bifidobacterium species colonies growing on blood agar are irregular in size, smooth, entire, convex, and non-hemolytic, ranging from gray-white to light yellow. The gram stain appearance of the slender gram positive bacilli with extensive branching and terminal protuberances that simulate "dog bones" is distinctive, rather than "box car" in shape. Lecithinase is not produced on egg-yolk agar. Culture recovery from patients with dental caries and aspiration pneumonia are more common. Propionibacterium acnes colonies are small, enamel white, circular and opaque on blood agar after anaerobic incubation. Beta-hemolysis is not observed. Observed in gram stains is gram positive cocco-bacilli that are arranged singly, in short chains and more distinctly in diphtheroidal clusters, rather than being "box car" in shape. Lecithinase is not produced on egg-yolk agar. P. acnes most commonly is a culture contaminant but on occasion serve as the cause of skin wound and shunt infections. Question Difficulty: Level 1

The anaerobe as included in this exercise was recovered from a wound infection of a suspected case of gas gangrene. Outbreaks of food-borne diarrhea following ingestion of contaminated meat products have been related to this isolate. On anaerobic blood agar, colonies as illustrated in the upper photograph are small, smooth, light gray-yellow and surrounded by a distinctive double zone of beta hemolysis (arrows). On gram stain, as illustrated in the lower photomicrograph, are large, non-spore forming, "box-car" shaped gram positive bacilli. A key biochemical reaction is the production of lecithinase by colonies growing on egg-yolk agar. With these observations, select from the multiple choices the presumptive identification of this isolate. Actinomyces israeli Bifidobacterium species Propionibacterium acnes Clostridium perfringens

Supravital stain The correct answer is supravital stain. To visualize Heinz bodies, smears must be prepared after staining an aliquot of fresh whole blood with a supravital stain such as new methylene blue or brilliant cresyl blue. Heinz bodies would not stain with a Prussian blue or Wright-Giemsa stain. Question Difficulty: Level 6

The arrows in the image point to Heinz bodies in erythrocytes. Which of the following stains was used to confirm the presence of these inclusions? Prussian blue stain Wright-Giemsa stain Supravital stain Any of the above stains

Monomacrophages The arrows in Image D indicate monocyte/macrophages. The cells have abundant cytoplasm with a lacy appearance. Question Difficulty: Level 1

The arrows in the images below indicate cells that may be observed in CSF samples. Match each image to the cell's identification. Choroidal cells Monomacrophages Presumptive malignant cells Lymphocytes

Cell A Cell A is a reticulocyte. RNA present in reticulocytes will appear as darker inclusions, similar to how they appear with new methylene blue stain. Reticulocyte inclusions are fewer in number than inclusions seen in hemoglobin H bodies. Cell B is a normal cell. A cell stained with brilliant cresyl blue in which unstable hemoglobin is not present or has not yet precipitated will appear to have a smooth surface with no inclusions. Hemoglobin H bodies are seen in cell C. The inclusions are faint blue and appear to be on the outside of the cell, resembling sugar on a gumdrop; but they are just inside the cell's membrane and push outward. Question Difficulty: Level 5

The attached picture is from a blood smear stained with brilliant cresyl blue, a supravital stain. Select which cell(s) would be identified as reticulocyte. Cell A Cell B Cell C Cells A and B

Micrococcus luteus The photographs illustrate a gram positive coccus that is susceptible to 0.04µg bacitracin ("A" disk) and resistant to furazolidone along with a gram stain morphology of tetrads (an arrangement of four bacterial cells). This presentation characteristically represents a Micrococcus species. Micrococcus luteus can be also be recognized by its bright yellow pigmentation on culture media. Micrococcus species can also be isolated from immunocompromised patients and this isolate was obtained from a patient undergoing continuous peritoneal dialysis. Staphylococcus aureus, Staphyloccus cohnii, and Staphylococcus epidermidis are incorrect as they are resistant to bacitracin and susceptible to furazolidone. In addition, the gram stain morphology of Staphylococcus species is gram positive cocci in clusters. In addition, lysostaphin can be used to differentiate Micrococcus species from Staphylococcus species as Micrococcus species is resistant and Staphylcoccus species is sensitive to lysostaphin. Question Difficulty: Level 5

The bacterial species illustrated in these photographs was recovered from septic peritoneal fluid of a patient undergoing continuous peritoneal dialysis. The most likely identification is: Micrococcus luteus Staphylococcus aureus Staphylococcus cohnii Staphylococcus epidermidis

Oxidizer The development of a yellow color by a bacterial species inoculated into OF medium indicates the production of acid from the carbohydrate contained. The reaction seen in this photograph; that is, acid production only in the oxygen exposed, uncovered tube, is indicative of an oxidizer. OF medium is used to determine if an organism can use carbohydrates oxidatively, fermentatively, or not at all. In OF medium, positive reactions are indicated by a yellow color, as the bromothymol blue indicator becomes yellow in an acidic environment. Green or blue-green are alkaline reactions and are interpreted as negative. A carbohydrate fermenter would produce a yellow pigmentation in both tubes the open and the closed tubes. Aerobes are microorganisms that live and grow in the presence of oxygen and does not refer to its ability to use carbohydrates. This organism is not a fermenter because fermenters give a positive (yellow) reaction in both the open and closed (tube covered with mineral oil) tubes. A non-oxidizer or nonsaccharolytic organism would produce no color change in either of the tubes, as the carbohydrate is not utilized by either mode of metabolism. Both tubes would appear blue/green or blue, indicating an alkaline reaction. Question Difficulty: Level 5

The bacterial species producing the set of reactions seen in the oxidative/fermentative (OF) glucose tubes illustrated in this photograph at the right is a (an): Fermenter Aerobe Oxidizer Nonoxidizer

Life-threatening septicemia Vibrio vulnificus has been incriminated in several cases of fatal septic infection, either after ingestion of contaminated seafood or following wound infections upon exposure in contaminated sea water (Janda JM, et al: Clin Micribiol Rev 1:245-267, 1988). This bacterial species has the particular predilection for reaching the blood stream, either by invading the intestinal mucosa in cases of gastrointestinal infection or via the subcutaneous lymphatics in wound infections. A diarrheal syndrome is usually not part of the picture and electrolyte imbalance usually does not ensue (Infection with V.cholerae results in fluid loss and severe dehydration and hypotension). The wound infections caused by Vibrio vulnificus do not produce gas gangrene. Question Difficulty: Level 7

The colonies growing on the surface of a thiosulfate citrate bile sucrose (TCBS) agar plate (the green color indicates lack of sucrose fermentation) were identified as Vibrio vulnificus. The serious complication of infections with this bacterial species is: Life-threatening septicemia Cholera-like diarrheal syndrome Severe electrolyte imbalance Progressive cellulitis and gas gangrene

Pseudomonas aeruginosa Although Pseudomonas aeruginosa may produce mucoid colonies on MAC agar, it does not ferment lactose, which is evident from the pink pigmentation of the colonies. K. pneumoniae produce mucoid, lactose fermenting colonies on MAC agar. E. aerogenes can produce lactose fermenting colonies on MAC agar. The colonies may be mucoid. E. coli can produce both lactose and non-lactose fermenting colonies but the lactose fermenting colonies on MAC agar are more common. Question Difficulty: Level 6

The colonies shown in the blood (BAP) agar (upper) and MacConkey (MAC) agar (lower) biplate are a 24 hour growth from an aerobic blood culture bottle that became positive at 12 hours after inoculation. The appearance of the colonies on MAC agar rules out the following bacterial species: Pseudomonas aeruginosa Klebsiella pneumoniae Enterobacter aerogenes Escherichia coli

Histoplasmosis The correct answer is histoplasmosis. The colonies seen growing on the blood agar are gray-white and have a delicate cob-web appearance. This appearance plus the delayed growth is characteristic of one of the dimorphic fungi. The lactophenol blue mount reveals delicate background hyphae and the production of macroconidia with a conspicuous prickly surface, characteristic of Histoplasma capsulatum. The mold form of Coccidioides immitis produces alternately staining arthroconidia. Blastomyces dermatitidis and Paracoccidioides brasiliensis produce single, smooth microconidia, each borne on a single, thin conidiophore ("lollipops"). Question Difficulty: Level 5

The colonies shown in the upper image were obtained on blood agar from a sputum specimen after 10 days of incubation at 30°C. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The diagnosis is most likely: Coccidioidomycosis Blastomycosis Histoplasmosis Paracoccidiodomycosis

Penicillium Penicillium species typically produce green, granular, rugose colonies as illustrated in this illustration. Many species within this genus are contaminants. Penicillium marneffei is one of the human pathogens within the genus causing bronchopulmonary penicilliosis or chronic allergic sinusitis. Coccidiodes immitus causes coccidioidomycosis, a systemic infection. The colony morphology is described as a white, fluffy, cobweb-like colony that grows typically in 3-5 days. The infection begins as a respiratory infection after the inhalation of the spores followed possibly by dissemination to organs, meninges, bone, lymph nodes, and subcutaneous tissue. Rhizopus is a hyaline, rapid growing mold (within 24 hours) that is described as fluffy, white to gray or brown growth. It is an opportunistic organism that may cause a rapidly progressive infection with a high morbidity and mortality rate, especially in diabetic patients. Trichophyton species are the cause of cutaneous tinea (ringworm) infections of the hair, skin, and nails. The colony morphology is described differently for different species; white, pink, yellow, or deep violet in color. Question Difficulty: Level 3

The hyaline mold colony represented in the composite picture is approximately 8 days old. The most likely genus is: Coccidiodes Rhizopus Penicillium Trichophyton

Gliocladium species All of the species listed in this exercise produce microconidia that aggregate in clusters rather than form chains. The clusters of conidia with Gliocladium species are supported by multiple conidiophores as shown in this photomicrograph, much as the cupped fingers would support a tennis ball. The microconidia of both Fusarium species and Acremonium species are loosely held, elongated, and arranged in an Oriental letter pattern. The conidia of both Gliocladium species and Trichoderma species are spherical and aggregate in tight clusters or balls. The conidia clusters of Trichoderma species are supported by single, tapered phialides that extend laterally from the hyphae. Question Difficulty: Level 7

The hyaline mold illustrated in this photomicrograph can be identified as: Trichoderma species Acremonium species Fusarium species Gliocladium species

Curvularia species Curvularia species are rapidly growing pigmented mold that is known to cause phaeohyphomycoses and sinusitis. It produces septate hyphae, conidiophores that are bend where the conidia attach (geniculate, and curved conidia. The curve in the conidia is due to the swollen central cell. Bipolaris species are rapidly growing dematiaceous mold with geniculate conidiophores but the conidia are fusoid in shape as the central cell is not swollen. It is also capable of causing phaeohyphomycoses and sinusitis. Alternaria species are a dematiaceous mold that causes phaeohyphomycosis, sinusitis as well as ulcers and onychomycosis of the skin and nails. Microscopically, this organism is described as producing septate hyphae with simple conidiophores that bear a chain of brown conidia. The conidia contain both horizontal and longitudinal septa. Cladophialophora species are dematiaceous molds that cause chromoblastomycosis and phaeohyphomycosis. Microscopically, they produce long, branching septate hyphae that give rise to branching chains of pigmented blastoconidia. The cells that produce the branching chains are called 'shield cells'. Question Difficulty: Level 8

The illustration demonstrates a dematiaceous mold that is known to cause phaeohyphomycoses and sinusitis. It produces septate hyphae, geniculate conidiophores and multi-celled, curved conidia with a swollen central cell. The most likely identification is: Bipolaris species Alternaria species Curvularia species Cladophialophora species

Leukemia with CNS involvement The arrows point to immature cells, the prominent nucleoli and large nucleus to cytoplasm ratio probably suggest blasts, which may indicate leukemia with CNS involvement. Blasts are not associated with allergic reactions (eosinophils), bacterial meningitis (neutrophils), or viral meningitis (lymphocytes). Question Difficulty: Level 4

The image is a Wright-Giemsa stained smear (1000x) of cerebrospinal fluid (CSF). The arrows point to cells that may indicate which of the following conditions? Allergic reaction Bacterial meningitis Leukemia with CNS involvement Viral meningitis

Presumptive malignant cells The cells that are indicated by the arrows are presumptive malignant cells. The characteristics that help to identify these, and the surrounding cells, as a malignant cells include: giant cells, cellular crowding, high nuclear to cytoplasm (N/C) ratio, non-uniform nuclei, irregular nuclear membranes, multinucleation, and vacuolation. Question Difficulty: Level 4

The image is a Wright-Giemsa stained smear (1000x) of cerebrospinal fluid (CSF). What is the identification of the cells that are indicated by the arrows? Ependymal cells Atypical lymphocytes Presumptive malignant cells Immature white blood cells

Metastasis The nucleus in this cell is abnormal and appears to have divided. This finding correlates with the presence of metastasis in the CSF. A broad spectrum of lymphocytes and monocytes would be present in a case of viral meningitis. An allergic reaction will show predominantly eosinophils. Cerebral hemorrhage would show predominantly RBCs. Question Difficulty: Level 5

The image is a stained smear of cerebrospinal fluid. The cell in this slide could be caused by what condition? Viral meningitis Allergic reaction Cerebral hemorrhage Metastasis

MCV increased, RDW increased The image contains many large red blood cells; the MCV would be increased. Comparing the cell sizes to the normal lymphocyte in the field, there are some normal size red blood cells as well. The RDW would be increased. The MCV would not be within normal limits or decreased since large cells or macrocytes are present. The RDW would not be within normal limits since there is variation in the size of RBCs present on the peripheral smear. Question Difficulty: Level 4

The image on the right is a representative field from a peripheral blood smear. What would you expect to see on the automated blood count? MCV within normal limits, RDW within normal limits MCV decreased, RDW decreased MCV increased, RDW increased MCV increased, RDW within normal limits

Chrysosporium

The images to the right show a 4-day-old colony grown on Sabouraud's Dextrose agar (left image). It was recovered from what was considered a "contaminant" from a bacterial culture. The image on the right is a high power photomicrograph of a methylene-blue stained mount prepared from the surfaces of the colony. With these observations, select the fungus genus from the choices below. Scedosporium Chrysosporium Sepedonium Beauveria

Fiber artifact This is a fiber artifact. Fiber artifacts can contaminate a urine specimen from clothing and diapers and can be confused with casts by inexperienced techs. To differentiate fiber artifacts from most casts, the specimen can be exained under polarized light. Fibers polarize while most casts do not. Hyaline casts generally appear as colorless, homogeneous, and transparent with rounded ends. They can also be seen as a result of dehydration, after diuretic therapy, in renal disease, and transiently as a result of exercise. Cystine crystals are present in acidic urine, are typically colorless, and have a characteristic hexagonal shape (also described as appearing similar to a benzene ring). These crystals are associated with cystinuria. Granular casts are composed of plasma protein aggregates and cellular remnants. They usually indicate renal parenchymal disease, or allograft rejection. Granular casts appear as cylinders of coarse, or fine, highly refractive particles. Question Difficulty: Level 2

The microscopic finding illustrated in this image is a _____? Hyaline cast Fiber artifact Cystine crystal Granular cast

An assessment of the myeloid to erythroid (M:E) ratio is part of every bone marrow evaluation. Which of the following does not apply to the M:E ratio? The erythroid total used in calculating the M:E ratio is the sum of all the nucleated red cell precursors. The myeloid total used in calculating the M:E ratio is the sum of all non-RBC cell types found in the marrow. White blood cells used in the myeloid tally/total used to calculate the M:E ratio include neutrophil precursors as well as eosinophil precursors and basophil precursors. The M:E should always be interpreted in context with the overall bone marrow cellularity.

The myeloid total used in calculating the M:E ratio is the sum of all non-RBC cell types found in the marrow. The M:E ratio is calculated from the total granulocyte precursors and the total erythroid precursors. It does not include non-myeloid nucleated cells such as lymphocytes, monocytes etc. It should always be interpreted in context with the overall bone marrow cellularity. Although laboratories may have slightly different reference ranges, the typical reference range for the M:E ratio is 2:1 - 4:1. Question Difficulty: Level 9

Bile solubility The bacterial cells of S. pneumoniae are bile soluble, as shown by the disappearance of the colonies in the area where a drop of 10% deoxycholate had been added to the surface of the agar, as illustrated in the image (yellow arrow). The colonies of viridans streptococci would remain intact and clearly visible. Question Difficulty: Level 7

The name of the rapid test seen in the image, often used to differentiate S. pneumoniae from viridans streptococci, in which a drop of 10% deoxycholate was placed on an area of growth, is:

Trichophyton rubrum Trichophyton rubrum is the correct response. The tinea pedis ("athlete's foot") skin lesion as observed in this exercise may be caused by select dermatophyte species from direct contact with spore-contaminated soil or water. The microscopic appearance of delicate hyphae from the sides of which are produce tear-shaped microconidia in a "birds on a fence" arrangement is characteristic of T. rubrum, the dermatophyte most commonly associated with this type of infection. Microsporum gypseum produces large, multi-segmented macroconidia with rounded ends produced from conidiophores borne laterally from nonbranching septate hyphae. Trichophyton tonsurans produces a mixture of club-shaped and spherical microconidia varying in size, but borne laterally and irregularly from nonbranching septate hyphae and not in the "birds on a fence" arrangement. Epidermophyton floccosum produces large club-shaped macroconidia, each with 3 - 5 cells separated by transverse septa, arranged in loose clusters rather than as "birds on a fence". Microconidia are not produced. Question Difficulty: Level 9

The scaling, pink-white appearance of the foot shown in the photograph is characteristic of "Athlete's Foot", a skin infection incurred by athletes after barefoot walks to and from the shower stall. A cottony gray-white fungal colony grew in 5 days from a skin scraping. The identification was made by the microscopic appearance of a mount made from the colony as illustrated in the photomicrograph. From these observations, select the name of the fungal species. Microsporum gypseum Trichophyton tonsurans Trichophyton rubrum Epidermophyton floccosum

Kingella kingae Kingella kingae is the correct response. Found as normal flora in the upper respiratory tract, particularly of children, this bacterial species may on occasion be the agent of pneumonia. Colonies growing on blood agar are pin-point in size, surrounded by narrow zones of soft beta hemolysis. In Gram stains, short, plump, gram-negative coccobacilli in pairs and short chains are observed. Chemical non-reactivity is evident except for a positive oxidase reaction and the selective carbohydrate utilization of dextrose and maltose. Additional biochemical reactions may be required in certain instances to rule out Neisseria species. Capnocytophaga species colonies grow poorly on sheep blood agar but when observed are indistinct, small, circular and smooth. Beta hemolysis is absent. Long, slender, fusiform gram-negative bacilli rather than cocco-bacilli in pairs and short chains are observed in gram stains. Distinctive from K. kingae is a negative biochemical reaction for indole and a positive carbohydrate reactions for fructose, lactose, and galactose in addition to dextrose and maltose . This isolate is typically recovered from a skin abscess at the site of a dog bite; or may be recovered from blood cultures in cases where the infection may spread. Cardiobacterium hominis colonies are small and non-hemolytic on sheep blood culture media. A presumptive identification can be made based on the observation of variable staining cocco-bacilli that often line up in rosette-like clusters. A positive indole reaction is distinct from that of K. kingae. Acid is produced from most carbohydrates including dextrose and maltose. Eikenella corrodens colonies are relatively large on both blood and chocolate agars. They are non-hemolytic on blood agar and are relatively larger on chocolate agar with distinct pitting of the surface of the colonies extending into the surrounding agar. Gram stains reveal slender, gram negative bacilli with rounded ends. Carbohydrate reactions are negative (asaccharolytic), including dextrose and maltose. The reduction of nitrates is the only positive reaction; the oxidase reaction is negative. Question Difficulty: Level 9

The small beta hemolytic bacterial colonies growing on blood agar as shown in the upper photograph were recovered from an induced sputum specimen from a young child with pneumonia. The colonies were slow growing, small, entire and show soft beta hemolysis. Short pump, gram-negative coccobacilli, lying singly, in pairs and short chains, are seen on gram stain as illustrated in the lower photomicrograph. Most strains are chemically non-reactive except for a positive oxidase reaction and acid produced from dextrose and maltose. From these observations, select from the multiple choices the name of the isolate as presented in this exercise. Capnocytophaga species Cardiobacterium hominis Eikenella corrodens Kingella kingae

Pseudomonas aeruginosa Pseudomonas aeruginosa is the correct response. The spreading, mucoid colonies growing both on Blood and MacConkey agars are characteristic. Colonies growing on MacConkey agar have a greenish pigmentation (not well demonstrated in this photograph) from the production of pyocyanin, best observed when growing on PseudoCel agar. Elongated gram-negative bacilli arranged in parallel bundles is also characteristic of P. aeruginosa. Oxidase, Arginine and Acetamide reactions are positive. Most isolates are resistant to Polymyxin B. Burkhoderia cepacia colonies on blood and MacConkey agar do not spread, are relatively small, smooth and entire with a buff yellow pigmentation. The colonies on MacConkey agar are light gray without green pigmentation indicating lack of pyocyanin production. Gram stains reveal short gram negative bacilli arranged singly and in loose clusters. Arginine and acetamide reactions are negative. Also resistant to polymyxin B. Comamonas acidovorans colonies on blood agar are tiny and non-spreading. Greenish pigmentation of colonies on MacConkey agar are negative indicating lack of pyocyanin production. Gram stain reveals straight or slightly curved gram-negative bacilli arranged singly. Arginine and acetamide reactions are negative. Pseudomonas stutzeri colonies on blood agar are distinctly flat and wrinkled with a yellow pigmentation. Colonies on MacConkey agar are gray white characteristic of a non-fermenter and devoid of pyocyanin green pigmentation. The gram stain appearance and most other biochemical characteristics are comparable to P. aeruginosa. Most strains of P. stutzeri are sensitive to polymyxin. Question Difficulty: Level 1

The spreading, mucoid colonies on blood and Mac-Conkey agars, as illustrated in the upper photograph are commonly recovered from specimens obtained from infected indwelling catheters, tracheostomies, burns and from spas or hot tubs. This non-fermenter can reproduce at increased temperatures. Colonies often have a greenish pigmentation from the distinctive production of pyocyanin. The gram stains as illustrate in the photomicrograph to the right reveal elongated gram negative bacilli arranged in parallel bundles. From these observations, select from the multiple choices the presumptive identification of this isolate. Burkholderia cepacia Comamonas acidovorans Pseudomonas stutzeri Pseudomonas aeruginosa

Glomerulonephritis Glomerulonephritis is a type of kidney disease in which the glomerulus (filters waste and fluids from the blood) is damaged. Damage to the glomeruli causes blood and protein to be lost in the urine. Hence, the image shows the presence of red blood cells. Diabetes mellitus, yeast infections, and pyruria are not associated with red blood cells in the urine. Question Difficulty: Level 3

The technologist in the urinalysis department received a sample for a microscopic examination. The image to the right shows the microscopic urinalysis. Which of the following conditions below would most closely match this patient's microscopic urinalysis morphology? Diabetes mellitus Glomerulonephritis Yeast infection Pyuria

A pneumococcus, penicillin resistant The Gram stain shown in the upper frame illustrates many background segmented neutrophils and many gram positive diplococci typical of Streptococcus pneumoniae. The high concentration of bacteria in pure culture virtually assures that it is the cause of the pneumonia. The >14mm zone around the "P" disk confirms the identification as Streptococcus pneumoniae, and the 8mm zone around the "OX" disk indicates that this strain is resistant to oxacillin (a zone diameter of less than 19 is considered resistant), and by extension resistant to penicillin as well. Therefore, "pneumococcus, penicillin resistant" is the correct response. Question Difficulty: Level 6

The upper photomicrograph illustrates a Gram stain of sputum obtained from a 55-year-old man with symptoms of bacterial pneumonia. The lower photograph represents the growth of an inoculum from the specimen on 5% sheep blood agar, on which had been placed an optochin ("P") and a 1 µg oxacillin disk. After 18 hours incubation at 37°C in 5% CO2, the zone around the optochin disk is 18mm and around the OX disk is 8mm. The interpretation is that the organism is most likely: Normal flora and not the cause of pneumonia A viridans group streptococcus, penicillin sensitive A pneumococcus, penicillin resistant A pneumococcus, penicillin sensitive

Artifacts These are artifacts; perhaps oil droplets. If they were red blood cells (RBCs), we would have expected to see evidence of this in the chemical (urinalysis strip) analysis. Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. Transitional epithelial cells are smaller than the squamous epithelial cells and appear in several shapes including spherical, polyhedral, and caudate. They line the renal pelvis, calyces, ureters, and bladder and usually appear in the urine after invasive procedures such as catheterization. Question Difficulty: Level 2

The urine macroscopic (urinalysis test strip) results were completely normal and within range. Upon viewing the microscopic, the technologist noticed these circular elements. What could be the identification of these elements? Red blood cells (RBCs) Artifacts Yeast Transitional epithelial cells

Bacillus anthracis ("malignant pustule") The photograph illustrates a "malignant pustule" characteristic of cutaneous anthrax infection. Such papules and pustules develop at the site of skin penetration of bacterial spores, most commonly found in wool, hair, hides and animal bones that are shipped from countries where the disease is endemic. The lower photograph demonstrates spore-forming, "boxcar-shaped" gram positive bacilli characteristic of Bacillus anthracis. Although a similar appearing pustule may be produced in some stage of evolution by each of the other bacterial species listed in this exercise, only B. anthracis produces bacterial cells with spores. F. tularensis, which causes tularemia (ulceroglandular in this instance) is a short, gram negative coccobacillus, E. rhusiopathiae, which causes erysipeloid, is a non-spore forming gram positive bacillus and Streptococcus pyogenes, which can be responsible for a number of skin infections, is a gram positive coccus in chains. Question Difficulty: Level 4

The well circumscribed, ulcerating pustule illustrated in the upper photograph evolved over 8 days following direct contact with raw animal hides that had been shipped from Central Asia. The lesion began as a small papule, which progressively enlarged, ultimately ulcerated and became covered centrally with a black eschar. The lower photomicrograph is a gram stain prepared from a colony that grew within 48 hours on blood agar. The most likely agent of this infection is: Bacillus anthracis ("malignant pustule") Erysipelothrix rhusiopathiae (erysipeloid) Francisella tularensis Streptococcus pyogenes (pyoderma)

Paracoccidioides brasiliensis Paracoccidioides brasiliensis produces large yeast cells, approximately the same size as those of Blastomyces dermatitidis (10 - 15 µm), except multiple buds are attached by narrow necks, giving the appearance of a "mariner's wheel." The yeast form of Blastomyces dermatitidis is a thick-walled yeast cell that characteristically produces a single bud attached by a broad base. The yeast forms of Sporothrix schenckii are elongated cells that have been called "cigar bodies." Candida albicans is a yeast not a dimorphic fungus. Question Difficulty: Level 4

The yeast forms of which of the following species of dimorphic fungi (represented in the image on the right) can be described as large yeast cells with multiple buds that are attached by narrow necks, giving the appearance of a "mariner's wheel?" Sporothrix schenkii Paracoccidioides brasiliensis Blastomyces dermatitidis Candida albicans

Homogeneous Speckled This is an example of a mix of homogeneous and speckled ANA patterns. In this sample notice the speckled ANA is the dominant pattern in the interphase cells (a) and some speckling in the area outside of the chromosomal area of the mitotics (b). Also notice the smooth staining of the chromosomal area of the metaphase mitotic cells (c). This represents the presence of a homogeneous ANA pattern. Question Difficulty: Level 7

There are two patterns present in this microscopic field from an antinuclear antibody ANA test. The test is viewed using fluorescent microscopy. One pattern can be seen in the interphase cells (a) and the area outside of the chromosomal area of the mitotics (b). The other pattern is recognizable in the chromosomal area of the metaphase mitotic cells (c). What are these two patterns? Centromere Homogeneous Speckled Nucleolar

Plasmodium falciparum Plasmodium falciparum is the intended selection. The placement of the tiny rings against the erythrocyte cell membrane is known as an "appliqué" form. This observation is distinctive for Plasmodium falciparum. It is important to recognize these forms in order to make an early diagnosis of falciparum malaria. These red cell membranes have adhesive properties that lead to their attachment of the endothelium of blood vessels, predisposing to thrombosis and infarction. Plasmodium vivax is an incorrect response. Early intra-erythrocytic ring forms of infection are more centrally placed. Applique forms beneath the outer membrane are not observed. The infected erythrocytes are increased in size, pale in color, and have Schuffner's dots distributed in the cytoplasm. Plasmodium malariae is an incorrect response. P. malariae developing ring trophozoites soon take the form of a "bridge" that extends between opposite borders of the infected erythrocyte. The erythrocyte is not enlarged, is normochromic, and is devoid of Schuffner's dots. Applique forms are not observed. Plasmodium ovale is an incorrect response. P. ovale developing trophozoites are similar to those of P. vivax often with a flowing or ameboid cytoplasm. However, the cytoplasm of P. ovale is normochromic and only a few scattered grains are seen in contrast to the dense distribution of Schuffner's dots with P. vivax. Applique forms are not obsersved. Question Difficulty: Level 9

These forms may be observed when screening through a peripheral blood smear. Closer observation of Giemsa-stained smears shows erythrocytes infested with a malarial parasite (upper center). Note the peripheral location of tiny ring forms immediately beneath the red cell membrane. From the multiple choices listed, select the most likely species identification. Plasmodium falciparum Plasmodium vivax Plasmodium malariae Plasmodium ovale

Traumatic tap The appearance of the CSF suggests a traumatic tap. This is indicated by the fact that there is decreasing amount of blood in the sequentially collected tubes; tube #1 contains visible red blood cells, but the amount of blood decreases in the other tubes. Normal CSF is clear and colorless. If the blood was the result of a subarachnoid hemorrhage, all three tubes would contain blood and the amount of blood in each tube would be consistent (unless a traumatic tap also occurred during collection of the sample). Bacterial meningitis would not show decreasing amounts of red blood cells from tube #1 thru tube #3. Question Difficulty: Level 2

These tubes of cerebrospinal fluid (CSF) arrive in the laboratory for evaluation. The tubes were numbered in the order in which they were obtained, with #1 being the first tube collected and #3 being the last tube collected. What may be indicated by the macroscopic appearance of the CSF? Normal spinal fluid Subarachnoid hemorrhage Traumatic tap Bacterial meningitis

Report the isolate as methicillin resistant Staphylococcus aureus. "Report the isolate as methicillin resistant Staphylococcus aureus" is the correct answer since the coagulase plasma is clotted indicating it is coagulase positive and the organism is growing on the 4% NaCl and 6 µg/mL oxacillin MRSA screen plate, demonstrating resistance to oxacillin, methicillin, and nafcillin. It is true that coagulase negative staphylococci should not be tested on MRSA screen agar but this isolate is coagulase positive. Methicillin susceptible Staphylococcus aureus would not grow on the MRSA screen plate. This test is as confirmatory as cefoxitin disk diffusion testing, so further testing is not needed and would delay treatment. Question Difficulty: Level 5

This Gram-positive coccus is catalase positive. The tests shown are a tube coagulase test inoculated with the isolate, and a MRSA screen plate containing 4% NaCl and 6 µg/mL of oxacillin. A 0.5 McFarland standardized inoculum of the isolate is inoculated to the plate. What step should you take next? Disregard the oxacillin test because coagulase negative staphylococci should not be tested on the oxacillin screen plate. Report the isolate as methicillin resistant Staphylococcus aureus. Report the isolate as methicillin susceptible Staphylococcus aureus. Test the isolate for cefoxitin susceptibility by disk diffusion testing.

Nucleolar This nucleolar pattern is characterized by staining in the nucleoli of the interphase cells (a). The nucleolar staining can display subtle variations in staining inside the nucleoli including smooth, speckled and clumpy. All are reported as ANA positive, Nucleolar. In this sample staining is present in the chromosomal area of the metaphase mitotic cells (b) along with some staining in the area outside of the chromosomal area. The staining of the mitotic cells can be different with different anti-nucleolar antibodies. An ANA pattern is determined by staining in the interphase cells and the mitotic cells are used to assist in interpretation. Note: (a) points to the nuclei of the interphase cells, the primary consideration for discerning the ANA pattern and (b) indicates a metaphase mitotic cell. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in identification of the ANA pattern. A homogeneous or diffused pattern characterizes anti-DNA nucleoprotein antibodies (i.e. antibodies to nDNA, dsDNA, ssDNA, DNP or histones). A homogeneous pattern is characterized by smooth staining in the nuclei of the interphase cells and smooth staining in the chromosomal areas of the metaphase mitotic cells. The nucleoli may or may not stain. Although vacuoles may be seen, the whole nucleus fluoresces evenly. In order for the ANA to be positive there must be a clearly discernible pattern in the nuclei of the interphase cells. Anti-Ro (SS-A) antibody is included in the non-histone protein (NhPs) and NhP-RNA complexes in systemic rheumatic diseases. The incidence of the antibody is 50% in cases of SLE. Detection of antibodies to SS-A/Ro varies according to the fixation method. alcohol diminishes or destroys the SS-A/Ro speckled ANA pattern, leading to a negative ANA. A speckled pattern occurs in the presence of antibody to any extractable nuclear antigen devoid of DNA or histone. The antibody is detected against the saline extractable nuclear antigens, anti-RNP and anti-Sm. A grainy pattern with numerous round dots of nuclear fluorescence, without staining of the nucleoli, is seen in this pattern type. Antibodies to anti-RNP has been found in patients with a wide variety of rheumatic disorders , including SLE. Antibodies to Sm antigen have been shown to be highly specific for patients with systemic lupus erythematosus (SLE). Question Difficulty: Level 5

This antinuclear antibody (ANA) test is viewed using fluorescent microscopy, which pattern is this? homogeneous SSA/Ro Nucleolar Speckled

Nucleolar Nucleolar is correct. This pattern is characterized by staining in the nucleoli of the interphase cells (a). The nucleolar staining can display subtle variations in staining inside the nucleoli including smooth, speckled and clumpy. All are reported as ANA positive, Nucleolar. In this sample staining is present in the chromosomal area of the metaphase mitotic cells (b) along with some staining in the area outside of the chromosomal area. The staining of the mitotics can be different with different anti-nucleolar antibodies. Remember the ANA pattern is determined by staining in the interphase cells and the mitotics are used to assist in interpretation. Question Difficulty: Level 5

This antinuclear antibody (ANA) test is viewed using fluorescent microscopy. The pattern is characterized by staining of the nucleoli in the nuclei of the interphase cells (a). Which pattern is this? Note: (a) points to the nuclei of the interphase cells, the primary consideration for discerning the ANA pattern and (b) indicates a metaphase mitotic cell. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in identification of the ANA pattern. Nuclear lamins SSA/Ro Nucleolar Large speckled

Which of the following bone marrow processing procedures is best suited for a patient who had a dry tap? Direct differential smear Touch preparations Concentrate (buffy coat) smears Crush smear

Touch preparations When a patient has a dry tap, the physician was unable to collect a bone marrow aspirate. Therefore, the only remaining specimen is a bone marrow biopsy. Touch preparations, also known as imprints, are made by touching the biopsy against the slide. Direct differential smears, concentrate (buffy coat) smears, and crush smears are all performed on bone marrow aspirates. Question Difficulty: Level 9

Elliptocytes The abnormal RBC shapes seen in this image are elliptocytes. Elliptocytes are seen in large numbers in hereditary elliptocytosis, which is a inherited trait. The RBCs take an elliptical shape due to a defect of one of the RBC skeletal proteins. Elliptocytes are also seen in lesser numbers in iron deficiency anemia and other conditions. Acanthocytes have spicules of varying length around the surface. They can be seen in abetalipoproteinemia, liver disease, and other conditions. Sickle cells are crescent or boat shaped. They are seen in sickle cell disorders. Echinocytes, also known as burr cells, have spicules that are equally spaced around the surface of the RBC. Question Difficulty: Level 1

What is the abnormal RBCs shape seen in this illustration? Elliptocytes Acanthocytes Sickle cells Echinocytes

Iron deficiency anemia The intended response is iron-deficiency anemia. The red blood cells in the image are microcytic and hypochromic which are typical findings in iron-deficiency anemia. Hypochromic RBC's have pale or hollow centers. In contrast, spherocytes are solidly stained, as they lack a central pallor. Both congenital spherocytosis and autoimmune hemolytic anemia present with spherocytes, therefore can be ruled out. There are no artifacts of staining present. Additional testing, such as iron studies and a complete medical history and/or repeat smears may be indicated for clarification. Note the absence of polychromasia in any red cells. This is further evidence of iron deficiency. Question Difficulty: Level 2

What is the condition most likely associated with the peripheral blood picture shown in the image on the right? Artifact of staining Congenital spherocytosis Iron deficiency anemia Autoimmune hemolytic anemia

B The 41s rule is broken across QC levels on day 17. This means that four consecutive controls are greater than ±1s from the mean. QC rules that are sensitive to SE are applied across both runs and levels to increase the probability of error detection. These are 22s , 41s , and 10×. Harr, Robert R. Medical Laboratory Science Review (Page 230). F.A. Davis Company. Kindle Edition.

What is the first day in the second half of the month that patient results would be rejected? A. Day 16 B. Day 17 C. Day 18 D. Day 19

Howell-Jolly bodies The small, spherical, dark blue-staining, non-refractile inclusions are known as Howell-Jolly bodies. They may represent nuclear (DNA) remnants, and may be found in pernicious anemia, hemolytic anemias, and often after splenectomy. Pappenheimer bodies appear as clusters of granules and contain iron. They are usually found at the periphery of the cell. Pappenheimer bodies can be found in sideroblastic anemia and other conditions. Heinz bodies can not be observed on a Wright stained blood smear. Heinz bodies are denatured or precipitated hemoglobin. They are found in G6PD deficiency and other conditions. Basophilic stippling appears as round granules varying in size that are distributed throughout the RBC. They are composed of aggregates of ribosomes. Basophilic stippling can be found in lead poisoning and other conditions. Question Difficulty: Level 2

What is the identification of the red blood cell inclusions indicated by the arrows on this peripheral blood smear image? Howell-Jolly bodies Pappenheimer bodies Heinz bodies Basophilic stippling

Calcium oxalate The crystals in the image below are composed of calcium oxalate. Calcium oxalate crystals have a refractile square envelope shape and can be seen in acid or neutral urine. They characteristically occur as octahedral or envelope shapes. Calcium oxalate crystals can also be viewed as having a Maltese cross when one focuses up and down through the crystal. Uric acid crystals are variably shaped: they occur as flat diamond (four-sized), rhombic, lemon-shaped, or rarely hexagonal shapes with a yellowish or yellowish brown coloration. They are present in acid urine. They are polarizable and show various colors when polarized. They may be present in normal urine. Triple phosphate crystals appear as colorless prisms with 3 to 6 sides and oblique ends, or as "feathery sleeves". The have been described as "coffin lid shaped", and can occur normally in alkaline urine. They may indicate the presence of an infection. Calcium carbonate crystals are colorless with dumbbell or spherical appearance and are found in alkaline urine. Question Difficulty: Level 2

What is the identification of these crystals seen in a urine with an acid pH? Uric acid Calcium oxalate Triple phosphate Calcium carbonate

Ependymal clump A key feature in identifying ependymal clumps is the presence of many similar-appearing nuclei without distinct lines of demarcation between cells. Basically, this cellular clump appears as one large cell, instead of many individual cells. On the other hand, choroid plexus clumps, mesothelial clumps, and macrophages do not display this "fused" morphology between cells. These types of cell clumps appear as individual cells gathered into a grouping. Cartilage cells usually occur singly. They are medium to large sized cells with cytoplasm that stain wine red (with deep wine red nucleus). Tumor cells often occur in clumps. Cells in the clump are dissimilar, and some are multinucleated with variation in nuclear size. There are usually no clear spaces between the cells. Lymphoblasts can occur in CSF in acute lymphoblastic leukemia (ALL). They have the characteristics of lymphoblasts seen in blood with basophilic cytoplasm. Question Difficulty: Level 8

What is the identification of this cellular clump found in CSF? Note the presence of many similar-appearing nuclei without distinct lines of demarcation between cells. Cartilage cell Tumor cell clump Ependymal clump Lymphoblast clump

Squamous epithelial cells (SECs) The cells in this image are squamous epithelial cells. These cells are some of the largest cells found in the urine, can even be seen under low-power fieldand, are not usually pathologic. These cells originate from the skin or outer urethra. They may appear as clumps of cells and have a very large irregular-shaped cytoplasm with a prominent centrally located nucleus. WBCs have a rough appearance and contain granules and multilobed nuclei which fill out the cytoplasm of the cell. Yeast cells can appear very similar to red blood cells in the urine at times. Yeast cells are usually oval and a bit smaller than red blood cells and can have a "budding" appearance. This morphology can aid in the differentiation between red cells and yeast. Acetic acid can be added to urine samples in order to lyse red blood cells and leave the remaining sediment intact. This is useful when attempting to differentiate between red cells and yeast. Question Difficulty: Level 1

What is the identity of the cells that are indicated by the arrow in this image? White blood cells (WBCs) Red blood cells (RBCs) Yeast Squamous epithelial cells (SECs)

Baciillus spp. The observation of gram positive bacilli with spores in a Gram stained preparation, obtained from a culture grown aerobically is diagnostic of Bacillus species. Nocardia species can be suspected if thin, filamentous, branching, poorly staining gram positive bacilli are observed. These bacterial cells are also partially acid-fast positive. Corynebacterium species typically produce short gram positive bacilli that have the property of aligning in an Oriental letter or "palisade" arrangement. Lactobacillus species produce regular, rectangular, non-spore forming gram positive bacilli, which have some tendency to align in short chains. Question Difficulty: Level 7

What is the most likely organism, based on the gram stain photomicrograph? Nocardia spp. Baciillus spp. Corynebacterium spp. Lactobacillus spp.

Segmented neutrophil The segmented neutrophil's nucleus has 2-5 distinct lobes with fine specific granules in the cytoplasm. The band neutrophil's nucleus is elongated and curved, without distinct lobes. The band neutrophil contains fine specific granules in the cytoplasm. The eosinophil has a nucleus with distinct lobes. The cytoplasm contains many orange granules. The basophil has a lobulated nucleus that can be covered by the dark blue granules in the cytoplasm. Question Difficulty: Level 1

What is the nucleated blood cell in this image? Segmented neutrophil Band neutrophil Eosinophil Basophil

0.07 mg/dL The standard deviation can be calculated by solving for the square root of the variance. The variance can be calculated by finding the sum of the squared differences between the group's mean and the individual data points. The group's mean is 0.97

What is the standard deviation of this set of data? 0.04 mg/dL 0.05 mg/dL 0.06 mg/dL 0.07 mg/dL

Crenated cell Crenated red cells usually occur as an artifact during the preparation of blood smears. This can occur if using a fan to dry the slide or when blowing on the slide. Sickle cells, also known as drepanocytes, are crescent shaped due to polymerized hemoglobin. Sickle cells are seen in sickle cell disorders. Thorn cells, more commonly called acanthocytes, are red cells with spicules of varying length that are irregularly distributed over the periphery. Acanthocytes can be seen in abetalipoproteinemia, liver disease, and other conditions. Fragmented cells, also known as schistocytes, are fragments of red cells. Schistocytes can be found in hemolytic anemias, disseminated intravascular coagulation (DIC). Question Difficulty: Level 4

What is the term used to describe the abnormal RBC shape seen in this illustration? Sickle cell Thorn cell Fragmented cell Crenated cell

Epithelial cells White blood cells Epithelial cells and white blood cells (specifically polymorphonuclear white blood cells) are the non-bacterial structures that are present in this microscopic field. Question Difficulty: Level 4

What non-bacterial structures are present in this microscopic field of a Gram-stained smear? (Choose ALL that apply) Epithelial cells Yeast Red blood cells White blood cells

Anisocytosis Anisocytosis is the abnormal variation in the size of red blood cells. Anisocytosis is also indicated on the complete blood count (CBC) by an increased red cell distribution width (RDW). Acanthocytosis would be indicated by the presence of acanthocytes (sometimes called "spurr cells"). Acanthocytes are abnormally shaped RBCs with various size spicules all over their cell membrane. They also have no central area of pallor. Polychromasia would be indicated by the presence of many cells appearing gray or bluish. Poikilocytosis would be indicated by the presence of many different shaped RBCs. Question Difficulty: Level 2

What term can be used to describe the abnormal variation in the size of the red blood cells seen in this image? Acanthocytosis Polychromasia Anisocytosis Poikilocytosis

Xanthochromia The term that is used to describe the color in these tubes of CSF is "xanthochromia." Xanthochromia is an abnormal color, usually yellow, orange, or pink, in the supernatant of the CSF sample. It may indicate that a subarachnoid hemorrhage (SAH) has occurred. Jaundice and icterus both describe a yellowing of the skin, mucous membranes, and eyes. Blood plasma/serum that is deep yellow is also described as icteric. Question Difficulty: Level 2

What term is used to describe the color in these tubes of cerebrospinal fluid (CSF)? Jaundice Xanthochromia Icterus Normal

All of the above Stuart Prower factor, or factor X, would cause abnormal PT, aPTT, and dRVVT test results as factor X is part of the common coagulation pathway and therefore measured in both the PT and aPTT test. In the dRVVT test, factor X is directly activated in the test principle; therefore, an abnormal result would be expected in this test as well if there was a deficiency in factor X. Factor X deficiency is extremely rare. Question Difficulty: Level 8

What test will be abnormal in a patient with Stuart-Prower Factor deficiency? Prothrombin Time (PT) Activated Partial Thromboplastin Time (APTT) Russel Viper Venom Test (dRVVT) All of the above

Polychromatophilic The cells that are indicated by the arrows in this slide are polychromatophilic red cells. They stain blue/gray with Wright stain and are larger than the normal mature red cells in the field. Another term used to describe these cells is recticulocytes. However, to definitvely determine whether a cell is a reticulocyte, a suprvital stain such as methylene blue should be used. Normochromic cells stain pinkish-orange on the Wright's stain, and do not have a bluish tint. Hypochromic red blood cells have an insufficient amount of hemoglobin in them, and thus stain pinkish with a larger than normal area of pallor. Red blood cells that look hyperchromic (appearing to have too much hemoglobin) generally do not have too much hemoglobin but rather refect an altered morphology. Such an example is a spherocyte which appears hyperchromic because the cell has assumed a sphere rather than a biconcave shape. Question Difficulty: Level 2

What type of cells are indicated by the arrows in this slide? Normochromic Hypochromic Polychromatophilic Hyperchromic

Blasts There are no blasts seen in this image. The lymphocytes seen here are mature, though from cytocentrifugation they can appear to have prominent nucleoli similar to blasts. The chromatin pattern of the nucleus in the lymphs shown is mature and clumped. Question Difficulty: Level 3

What types of cells are NOT present in this field of a cytocentrifuged CSF sample? Red cells Lymphocytes Neutrophils Blasts

Giardia duodenalis Giardia duodenalis (lamblia) is the correct identification. The pear-shaped or tear-drop shaped intra-luminal trophozoite (arrow) is distinctive for the two laterally placed nuclei and a flagellum extending from the posterior. This trophozoite may also be recognized as "old man face." If there is any reason to doubt the presumptive identification based on observation of the trophozoite morphology, particularly if the patient has no symptoms, Giardia antigen testing might be performed on a duodenal fluid aspirate. Chilomastix mesnili is an incorrect response. Chilomastix trophozoites are also pear-shaped, but have only a single large nucleus placed anteriorly next to the outer membrane, with a prominent cytosome adjacent to the nucleus. This flagellate is considered non-pathogenic and stool antigen testing for Giardia would be negative. Dientamoeba fragilis is an incorrect response. Although Dientamoeba trophozoites are somewhat pear-shaped, they have two distinctive dark staining nuclei with prominent karyosomes fragmented into granules. Giardia antigen tests would be negative. Trichomonas hominis is an incorrect response. Trichomonas trophozoites are tear-drop in shape and distinctively have a single dark-staining nucleus immediately beneath the anterior membrane. This flagellate is considered non-pathogenic and stool antigen testing for Giardia would be negative. Question Difficulty: Level 1

When parasites are observed in clinical stool specimens, antigen detection is the preferred method for identification, providing increased sensitivity over more common microscopy techniques. Several commercial products (DFA, EIAs, and rapid tests) are available. The H & E - stained tissue section of duodenum illustrates the presence of an intra-luminal intestinal trophozoite in which an antigen assay might be helpful in making a definitive identification. Select the presumptive identification from the choices listed. Chilomastix mesnili Giardia duodenalis Dientamoeba fragilis Trichomonas hominis

Pseudoallescheria boydii Pseudoallescheria boydii is the correct response. As both the "house mouse gray" colonies and portions of the microscopic view of the hyphae and conidia are consistent with Scedosporium species, the added observation of the sheath-like arrangement of conidiophores and the presence of ascospores containing small spherical conidia would indicate Pseudallescheria. Scedosporium no longer is considered to be in the genus Pseudallescheria. Even though the production of sheath--like conidiophores and conidia containing ascospores, Pseudallescheria is no longer considered to be a "sexual" form of Scedosporium. Chrysosporium colonies also are not distinctive, growing in 2 - 4 days with a gray, wooly surface. Microscopically spherical, sub-globose to pyriform conidia are borne singly rather than in clusters at the tips of long thin conidiophores, simulating a "lollipop". Sheath-like arrangement of conidiophores and ascospores are not observed. Sepedonium colonies are gray white with a cottony surface that is non-specific. Microscopically, large spherical, bluntly spiked macroconidia are borne singly and not in clusters from long, delicate conidiophores." Sheath-like arrangement of conidiophores and ascospores are not observed. Question Difficulty: Level 1

When working up a culture, Scedosporium species may presumptively be identified if colonies have a "house mouse" gray appearance and microscopically observed are long delicate condiophores from the tips of which are produced a single oval conidium ("lollipop"). In some cases, further examination of the microscopic mount may reveal the branching, sheath-like arrangement (graphium form) of conidiophores as seen in the top image, and/or the spherical conidia-containing ascospores seen in the lower image. From the multiple choices, indicate the fungal species to be recognized. Sepedonium species Chrysosporium species Scedosporium species Pseudoallescheria boydii

Heinz bodies

Which of the following inclusions, marked by the arrow, is seen on this smear made with a supravital stain? Döhle bodies Heinz bodies May-Hegglin anomaly Reticulocytes

A pipette should be wiped off: before lowering the meniscus to the calibration mark after lowering the meniscus to the calibration mark never if it is a volumetric pipette only if it is a TC (to contain) pipette

before lowering the meniscus to the calibration mark Pipettes should be wiped off to prevent excess solution from being expelled into the receiving container when the pipette releases its contents. The pipette should be wiped off PRIOR to lowering the contents to the meniscus in case some of the solution inside is wicked out from the wiping. Lowering the contents to the meniscus after wiping will ensure the most accurate volume to be dispensed by the pipette. Question Difficulty: Level 7

Cocci may arrange as diplococci, tetrads, chains and clusters. The morphologic arrangement of the genus Staphylococcus is singly diplococci chains clusters

clusters The characteristic morphology of Staphylococci is cocci in clusters which is described as grape-like clusters. Staphylococci do not exhibit the morphology of single cocci. Some bacterial species that exhibit the diplococcus arrangement include Streptococcus pneumoniae, which appear as lancet shaped cocci and Neisseria species which are small gram negative diplococci with adjacent ends flattened. Most of the streptococci and the enterococci have the morphology of cocci in chains. Question Difficulty: Level 8

Isolation and detection of Gardnerella vaginalis from vaginal secretions is improved by which of the following? utilization of human blood agar incubation at 35-37ºC cold enrichment utilization of Thayer-Martin agar

utilization of human blood agar Human blood agar is an enriched media that supports the growth of Gardnerella vaginalis. The media usually contains 5% human blood without the presence of inhibitors. G. vaginalis produces a characteristic diffuse beta-hemolysis in the presence of human blood, and can therefore be distinguished from other similar-appearing organisms. Question Difficulty: Level 7

A streptozyme test was performed, but the result was negative, even though the patient showed clinical signs of a streptococcal throat infection. What should be done next? A. Either ASO or anti-deoxyribunouclease B (anti-DNase B) testing B. Another streptozyme test using diluted serum C. Antihyaluronidase testing D. Wait for 3-5 days and repeat the streptozyme test

A A streptozyme test is used for screening and contains several of the antigens associated with streptococcal products. Because some patients produce an antibody response to a limited number of streptococcal products, no single test is sufficiently sensitive to rule out infection. Clinical sensitivity is increased by performing additional tests when initial results are negative. The streptozyme test generally shows more false positives and false negatives than ASO and anti-DNase. A positive test for antihyaluronidase occurs in a smaller number of patients with recent streptococcal infections than ASO and anti-DNase. Harr, Robert R. Medical Laboratory Science Review (Page 96). F.A. Davis Company. Kindle Edition.

Select the best donor for a man, blood type AB, in need of a kidney transplant. A. His brother, type AB, HLA matched for class II antigens B. His mother, type B, HLA matched for class I antigens C. His cousin, type O, HLA matched for major class II antigens D. Cadaver donor, type O, HLA matched for some class I and II antigens

A A twin or sibling donor of the same blood type and HLA matched for class II antigens is the best donor in this situation. Class II antigens (HLA-D, HLA-DR, DQ, and DP) determine the ability of the transplant recipient to recognize the graft. The HLA genes are located close together on chromosome 6, and crossover between HLA genes is rare. Siblings with closely matched class II antigens most likely inherited the same class I genes. The probability of siblings inheriting the same HLA haplotypes from both parents is 1:4. Harr, Robert R. Medical Laboratory Science Review (Page 111). F.A. Davis Company. Kindle Edition.

SITUATION: A peripheral smear shows 75% blasts. These stain positive for both Sudan Black B (SBB) and peroxidase. Given these values, which of the following disorders is most likely? A. Acute myelocytic leukemia (AUL). B. CML C. Acute undifferentiated leukemia (AUL) D. Acute lymphocytic leukemia (ALL).

A AML blasts stain positive for Sudan Black B and peroxidase. Usually, fewer than 10% blasts are found in the peripheral smear of patients with CML, unless there has been a transition to blast crisis. The organelles in the cells of AUL are not mature enough to stain positive for SBB or peroxidase. Blasts in ALL are characteristically negative with these stains. Harr, Robert R. Medical Laboratory Science Review (Page 23). F.A. Davis Company. Kindle Edition.

What would be the most likely designation by the WHO for the FAB AML M3 by the French-American-British classification? A. AML with t(15;17) B. AML with mixed lineage C. AML with t(8;21) D. AML with inv(16)

A AML with t(15;17) is classified under the category of AML with Recurrent Genetic Abnormalities by the WHO. Acute promyelocytic leukemia (PML; known as M3 under the FAB system) is composed of abnormal promyelocytes with heavy granulation, sometimes obscuring the nucleus, and abundant cytoplasm. Acute promyelocytic leukemia (APL) contains a translocation that results in the fusion of a transcription factor called PML on chromosome 15 with the alpha (α)-retinoic acid receptor gene (RARα) on chromosome 17. Harr, Robert R. Medical Laboratory Science Review (Page 25). F.A. Davis Company. Kindle Edition.

Factor V Leiden promotes thrombosis by preventing: A. Deactivation of factor Va B. Activation of factor V C. Activation of protein C D. Activation of protein S

A Factor V Leiden is a single-point mutation in the factor V gene that inhibits factor Va inactivation by protein C. Activated protein C enhances deactivation of factors Va and VIIIa. Harr, Robert R. Medical Laboratory Science Review (Page 61). F.A. Davis Company. Kindle Edition.

The directions for a slide agglutination test instruct that after mixing the patient's serum and latex particles, the slide must be rotated for 2 minutes. What would happen if the slide were rotated for 10 minutes? A. Possible false-positive result B. Possible false-negative result C. No effect D. Depends on the amount of antibody present in the sample

A Failure to follow directions, as in this case where the reaction was allowed to proceed beyond the recommended time, may result in a false-positive reading. Drying on the slide may lead to a possible erroneous positive reading. Harr, Robert R. Medical Laboratory Science Review (Page 86). F.A. Davis Company. Kindle Edition.

The following results were obtained on a patient: normal platelet count and function, normal PT, and prolonged APTT. Which of the following disorders is most consistent with these results? A. Hemophilia A B. Bernard-Soulier syndrome C. von Willebrand's disease D. Glanzmann's thrombobasthenia

A Hemophilia A is associated with the deficiency of factor VIII resulting in bleeding and an abnormal APTT. The platelet number and function are normal in this disorder. Von Willebrand's disease is a disorder of platelet adhesion associated with decreased VWF and factor VIII, causing an abnormal platelet function test and an abnormal APTT test. Both Glanzmann's thrombasthenia and Bernard-Soulier syndrome cause deficient platelet aggregation, but do not cause an abnormal APTT. Harr, Robert R. Medical Laboratory Science Review (Page 54). F.A. Davis Company. Kindle Edition.

If a patient has a positive direct antiglobulin test, should you perform a weak D test on the cells? A. No, the cells are already coated with antibody B. No, the cell are Rhnull C. Yes, the immunoglobulin will not interfere with the test D. Yes, Rh antigens are enhanced in protein media

A If a person has a positive DAT, the red cells are coated with immunoglobulin (anti-IgG and antiC3d, or both). If a test for weak D were performed, the test would yield positive results independent of the presence or absence of the D antigen on the red cells. Harr, Robert R. Medical Laboratory Science Review (Page 130). F.A. Davis Company. Kindle Edition.

What has happened in a titer, if tube Nos. 5-7 show a stronger reaction than tube Nos. 1-4? A. Prozone reaction B. Postzone reaction C. Equivalence reaction D. Poor technique

A In tubes Nos.1-4, insufficient antigen is present to give a visible reaction because excess antibody has saturated all available antigen sites. After dilution of antibody, tubes Nos.1-4 have the equivalent concentrations of antigen and antibody to allow formation of visible complexes. Harr, Robert R. Medical Laboratory Science Review (Page 86). F.A. Davis Company. Kindle Edition.

Which of the following conditions will most likely result in a false-negative DAT test? A. Insufficient washing of RBCs B. Use of heavy chain-specific polyclonal anti-human Ig C. Use of excessive centrifugal force D. Use of a sample obtained by finger puncture

A Insufficient washing can cause incomplete removal of excess or unbound immunoglobulins and other proteins, which may neutralize the antiglobulin reagent. Harr, Robert R. Medical Laboratory Science Review (Page 104). F.A. Davis Company. Kindle Edition.

What type of blood should be given to an individual who has an anti-Le^b that reacts 1+ at the IAT phase? A. Blood that is negative for the Le^b antigen B. Blood that is negative for both the Le^a and Le^b antigens C. Blood that is positive for the Le^b antigen D. Lewis antibodies are not clinically significant, so any type of blood may be given

A Lewis antibodies are generally not considered clinically significant unless they react at 37°C or at the IAT phase. The antibody must be honored in this scenario. Harr, Robert R. Medical Laboratory Science Review (Page 134). F.A. Davis Company. Kindle Edition.

A patient was suspected of having lymphoproliferative disorder. After several laboratory tests were completed, the patient was found to have an IgM(kappa) paraprotein. In what sequence should the laboratory tests leading to this diagnosis have been performed? A. Serum protein electrophoresis (SPE) followed by immunofixation electrophoresis (IFE) B. Immunoglobulin levels followed by SPE C. Total lymphocyte count followed by immunoglobulin levels D. Immunoglobulin levels followed by urine protein electrophoresis

A Serum protein electrophoresis should be performed initially to detect the presence of an abnormal immunoglobulin that demonstrates restricted electrophoretic mobility. A patient producing only monoclonal light chains may not show any abnormal serum finding because the light chains may be excreted in the urine. A positive finding for either serum or urine should be followed by IFE on the positive specimen. This is required to confirm the presence of monoclonal immunoglobulin and to identify the heavy and light chain type. Harr, Robert R. Medical Laboratory Science Review (Page 85). F.A. Davis Company. Kindle Edition.

Which test is most likely to be positive in the tertiary stage of syphilis? A. FTA-ABS B. RPR C. VDRL D. Reagin screen test (RST)

A The FTA-ABS or one of the treponemal tests is more likely to be positive than a nontreponemal test in the tertiary stage of syphilis. In some cases, systemic lesions have subsided by the tertiary stage and the nontreponemal tests become seronegative. Although the FTA-ABS is the most sensitive test for tertiary syphilis, it will be positive in both treated and untreated cases. Harr, Robert R. Medical Laboratory Science Review (Page 89). F.A. Davis Company. Kindle Edition.

A patient receives a transfusion of packed red cells and fresh frozen plasma and develops an anaphylactic, nonhemolytic reaction. She reports receiving a transfusion 20 years earlier. She had no reaction to the previous transfusion, but she did feel "poorly" a few weeks later. Which of the following transfused substrates most likely elicited the reaction? A. IgA B. Group A antigen C. Rho (D) antigen D. An antibody belonging to the Duffy system

A The fact that this is a nonhemolytic reaction suggests that a non-red cell antigen may be involved. Selective IgA deficiency occurs in approximately 1 in 700 individuals and is often asymptomatic. Individuals deficient in IgA may make an antibody against the α heavy chain if they are exposed to IgA via a transfusion. This antibody may lead to a serum sickness reaction if the IgA is still present after antibody formation. This could explain the "poor feeling" the patient had after the initial transfusion. A subsequent transfusion may lead to an Arthus reaction if IgG anti-IgA is present or an anaphylactic reaction if IgE anti-IgA is present. Harr, Robert R. Medical Laboratory Science Review (Page 105). F.A. Davis Company. Kindle Edition.

What screening test should be performed first in a young patient suspected of having an immune dysfunction disorder? A. Complete blood count (CBC) and white cell differential B. Chemotaxis assay C. Complement levels D. Bone marrow biopsy

A The first screening tests performed in the initial evaluation of a young patient who is suspected of having an immune dysfunction are the CBC and differential. White blood cells that are decreased in number or abnormal in appearance may indicate further testing. Harr, Robert R. Medical Laboratory Science Review (Page 106). F.A. Davis Company. Kindle Edition.

Which results would be expected for the prothrombin time (PT) and activated partial thromboplastine time (APTT) in a patient with polycythemia? A. Both prolonged B. Both shortened C. Normal PT, prolonged APTT D. Both normal

A The volume of blood in a polycythemic patient contains so little plasma that excess anticoagulant remains and is available to bind to reagent calcium, thereby resulting in prolongation of the PT and APTT. For more accurate results, the plasma:anticoagulant ratio can be modified by decreasing the amount of anticoagulant in the collection tube using the following formula: (0.00185)(V)(100-H) = C, where V = blood volume in mL; H = patient's Hct; and C = volume (mL) of anticoagulant. A new sample should be drawn to rerun the PT and APTT. Harr, Robert R. Medical Laboratory Science Review (Page 44). F.A. Davis Company. Kindle Edition.

TTP differs from DIC in that: A. APTT is normal in TTP but prolonged in DIC B. Schistocytes are not present in TTP but are present in DIC C. Platelet count is decreased in TTP but normal in DIC D. PT is prolonged in TTP but decreased in DIC

A Thrombotic thrombocytopenic purpura is a platelet disorder in which platelet aggregation increases, resulting in thrombocytopenia. Schistocytes are present in TTP as a result of microangiopathic hemolytic anemia; however, the PT and APTT are both normal. In DIC, the PT and APTT are both prolonged, the platelet count is decreased, and schistocytes are seen in the peripheral smear. Harr, Robert R. Medical Laboratory Science Review (Page 49). F.A. Davis Company. Kindle Edition.

What should be done if all forward and reverse ABO results are negative? A. Perform additional testing such as typing with anti-A1, lectin, and anti-A,B B. Incubate at 22 degrees Celsius or 4 degrees Celsius to enhance weak expression C. Repeat the test with new reagents D. Run an antibody identification panel

B All negative results may be due to weakened antigens or antibodies. Room temperature or lower incubation temperature may enhance expression of weakened antigens or antibodies. Harr, Robert R. Medical Laboratory Science Review (Page 127). F.A. Davis Company. Kindle Edition.

When performing platelet aggregation studies, which set of platelet aggregation results would most likely be associated with Bernard-Soulier syndrome? A. Normal platelet aggregation to collagen, ADP, and ristocetin B. Normal platelet aggregation to collagen, ADP, and epinepherine; decreased aggregation to risotcetin C. Normal platelet aggregation to epinepherine and ristocetin; decreased aggregation to collagen and ADP D. Normal platelet aggregation to epinepherine, ristocetin, and collagen; decreased aggregation to ADP

B Bernard-Soulier syndrome is a disorder of platelet adhesion caused by deficiency of glycoprotein Ib. Platelet aggregation is normal in response to collagen, ADP, and epinephrine but abnormal in response to ristocetin. Harr, Robert R. Medical Laboratory Science Review (Page 49). F.A. Davis Company. Kindle Edition.

What effect does selecting the wrong gate have on the results when cells are counted by flow cytometry? A. No effect B. Failure to count the desired cell population C. Falsely elevated results D. Impossible to determine

B Gating is the step performed to select the proper cells to be counted. Failure to properly perform this procedure will result in problems in isolating and counting the desired cells. It is impossible to determine if the final result would be falsely elevated or falsely lowered by problems with gating. Harr, Robert R. Medical Laboratory Science Review (Page 87). F.A. Davis Company. Kindle Edition.

Why is testing a pregnant woman for weak D not required? A. An Rh-negative fetus may yield false positive results in a fetal maternal bleed B. An Rh-positive fetus may yield false positive results in a fetal maternal bleed C. D antigen strength decreases during pregnancy D. D antigen strength increases during pregnancy

B If a weak D test is performed on a pregnant woman with no previous history, a false-positive weak D test may result from the presence of fetal blood if the fetus is Rh positive. A pregnant woman with weak D may be given Rh immune globulin without any harmful consequences. Therefore, weak D testing of pregnant women is not necessary. Harr, Robert R. Medical Laboratory Science Review (Page 132). F.A. Davis Company. Kindle Edition.

What would happen if the color reaction phase is prolonged in one tube or well of an ELISA test? A. Result will be falsely decreased B. Result will be falsely increased C. Result will be unaffected D. Impossible to determine

B If the color reaction is not stopped within the time limits specified by the procedure, the enzyme will continue to act on the substrate, producing a falsely elevated test result. Harr, Robert R. Medical Laboratory Science Review (Page 84). F.A. Davis Company. Kindle Edition.

What outcome results from improper washing of a tube or well after adding the enzyme-antibody conjugate in an ELISA system? A. Result will be falsely decreased B. Result will be falsely increased C. Result will be unaffected D. Result is impossible to determine

B If unbound enzyme-conjugated anti-immunoglobulin is not washed away, it will catalyze conversion of substrate to colored product, yielding a falsely elevated result. Harr, Robert R. Medical Laboratory Science Review (Page 84). F.A. Davis Company. Kindle Edition.

What is the most likely cause when a Western blot or ELISA is positive for all controls and samples? A. Improper pipetting B. Improper washing C. Improper addition of sample D. Improper reading

B Improper washing may not remove unbound enzyme conjugated anti-human globulin, and every sample may appear positive. Harr, Robert R. Medical Laboratory Science Review (Page 92). F.A. Davis Company. Kindle Edition.

An immunofluoresence microscopy assay (IFA) was performed, and a significant antibody titer was reported. Positive and negative controls performed as expected. However, the clinical evaluation of the patient was not consistent with a positive finding. What is the most likely explanation of this situation? A. The clinical condition of the patient changed since the sample was tested B. The pattern of fluoresence was misinterpreted C. The control results were misinterpreted D. The wrong cell line was used for the test

B In an IFA, for example, an antinuclear antibody (ANA) test, the fluorescence pattern must be correlated correctly with the specificity of the antibodies. Both pathological and nonpathological antibodies can occur, and antibodies may be detected at a significant titer in a patient whose disease is inactive. Failure to correctly identify subcellular structures may result in misinterpretation of the antibody specificity, or a false positive caused by nonspecific fluorescence. Harr, Robert R. Medical Laboratory Science Review (Page 85). F.A. Davis Company. Kindle Edition.

What is the most likely explanation when antibody tests for HIV are negative but a polymerase chain reaction test performed 1 week later is positive? A. Probably not HIV infection B. Patient is in the "window phase" before antibody production C. Tests were performed incorrectly D. Clinical signs may be misinterpreted

B In early seroconversion, patients may not be making enough antibodies to be detected by antibody tests. The period between infection with HIV and the appearance of detectable antibodies is called the window phase. Although this period has been reduced to a few weeks by sensitive enzyme immunoassays, patients at high risk or displaying clinical conditions associated with HIV disease should be tested again after waiting several more weeks. Harr, Robert R. Medical Laboratory Science Review (Page 91). F.A. Davis Company. Kindle Edition.

SITUATION: Cells type negative for all HLA antigen in a complement-dependent cytotoxicity assay. What is the most likely cause? A. Too much supravital dye was added B. Rabbit complement is inactivated C. All leukocytes are dead D. Antisera is too concentrated

B Inactive rabbit complement may not become fixed to antibodies that have bound test leukocytes; therefore, no lysis of cells will occur. When the supravital dye is added, all cells will appear negative (exclude the dye) for all HLAs. Harr, Robert R. Medical Laboratory Science Review (Page 111). F.A. Davis Company. Kindle Edition.

If the frequency of gene Y is 0.4 and the frequency of gene Z is 0.5, one would expect that they should occur together 0.2 (20%) of the time. In actuality, they are found together 32% of the time. This is an example of: A. Crossing over B. Linkage disequilibrium C. Polymorphism D. Chimerism

B Linkage disequilibrium is a phenomenon in which alleles situated in close proximity on a chromosome associate with one another more than would be expected from individual allelic frequencies. Harr, Robert R. Medical Laboratory Science Review (Page 124). F.A. Davis Company. Kindle Edition.

Which of the following abnormalities is consistent with the presence of lupus anticoagulant? A. Decreased APTT/bleeding complications B. Prolonged APTT/thrombosis C. Prolonged APTT/thrombocytosis D. Thrombocytosis/thrombosis

B Lupus anticoagulant interferes with phospholipids in the APTT reagent, resulting in prolongation of APTT. However, in vivo, lupus anticoagulant decreases fibrinolytic activity, causing an increased risk of thrombosis. Lupus anticoagulant does not result in a bleeding tendency unless there is a coexisting thrombocytopenia or other coagulation abnormality. Harr, Robert R. Medical Laboratory Science Review (Page 59). F.A. Davis Company. Kindle Edition.

Would an hCG test using a monoclonal antibody against the Beta-subunit of hCG likely be affected by an increased level of follicle-stimulating hormone (FSH)? A. Yes, the Beta-subunit of FSH is identical to that of hCG B. No, the test would be specific for the Beta-subunit of hCG C. Yes, a cross reaction would occur because of structural similarities D. No, the structure of FSH and hCG are not at all similar

B Luteinizing hormone, FSH, and hCG share a common α-subunit but have different β subunits. A test for hCG using a monoclonal antibody would be specific for hCG provided that the antibody was directed against an antigenic determinant on the carboxy terminal end of the β subunit. Harr, Robert R. Medical Laboratory Science Review (Page 110). F.A. Davis Company. Kindle Edition.

Serological tests for which disease may be give a false-positive result if the patient has Lyme disease? A. AIDS B. Syphilis C. Cold agglutinins D. Hepatitis C

B Lyme disease is caused by a spirochete and may give positive results with some specific treponemal antibody tests for syphilis. Harr, Robert R. Medical Laboratory Science Review (Page 97). F.A. Davis Company. Kindle Edition.

A flow cytometry scattergram of a bone marrow sample shows a dense population of cells located in-between normal lymphoid and normal myeloid cells. What is the most likely explanation? A. The sample was improperly collected B. An abnormal cell population is present C. The laser optics are out of alignment D. The cells are most likely not leukocytes

B Lymphoid cells and myeloid cells display in predictable regions of the scatterplot because of their characteristic size and density. Lymphoid cells cause less forward and side scatter from the laser than do myeloid cells. A dense zone of cells in between those regions is caused by the presence of a large number of abnormal cells, usually blasts. The lineage of the cells can be determined by immunophenotyping with a panel of fluorescent-labeled antibodies. Harr, Robert R. Medical Laboratory Science Review (Page 87). F.A. Davis Company. Kindle Edition.

Prothrombin G20210A is characterized by which of the following causes and conditions? A. Single mutation of prothrombin molecule/bleeding B. Single mutation of prothrombin molecule/thrombosis C. Decreased levels of prothrombin in plasma/thrombosis D. Increased levels of prothrombin in plasma/bleeding

B Prothrombin G20210A is defined as a single-point mutation of the prothrombin gene, resulting in increased concentration of plasma prothrombin and thereby a risk factor for thrombosis. Prothrombin G20210A is the second most common cause of inherited hypercoagulability (behind factor V Leiden). It has the highest incidence in whites from southern Europe. The thrombotic episodes generally occur before age 40. Harr, Robert R. Medical Laboratory Science Review (Page 61). F.A. Davis Company. Kindle Edition.

A technologist is having great difficulty resoling an antibody mixture. One of the antibodies is anti-Le^a. This antibody is not clinically significant in this situation, but it needs to be removed to reveal the possible presence of an underlying antibody of clinical significance. What can be done? A. Perform an enzyme panel B. Neutralize the serum with saliva C. Neutralize the serum with hydatid cyst fluid D. Use DTT (dithiothreitol) to treat the panel cells

B Saliva from an individual with the Le gene contains the Le a antigen. This combines with anti-Le a , neutralizing the antibody. Panel cells treated with DTT (0.2M) lose reactivity with anti-K and other antibodies, but not anti-Le a . Hydatid cyst fluid neutralizes anti-P1. Harr, Robert R. Medical Laboratory Science Review (Page 134). F.A. Davis Company. Kindle Edition.

A female patient at 28 weeks' gestation yields the following results: Patient cells: Anti-A 3+, Anti-B 4+ Patient serum: A1 cells negative, B cells 1+, O cells 1+ Which of the following could be causing the ABO discrepancy? A. Hypogammaglobulinemia B. Alloantibody in patient serum C. Acquired B D. Weak subgroup

B The patient is most likely an AB person who has formed a cold-reacting alloantibody reacting with B cells and O cells. An identification panel should be performed. An acquired B person or someone with hypogammaglobulinemia should not make antibody that would agglutinate O cells. Harr, Robert R. Medical Laboratory Science Review (Page 128). F.A. Davis Company. Kindle Edition.

Interpret the following results for HIV infection. ELISA: positive; repeat ELISA; negative; Western blot: no bands A. Positive for HIV B. Negative for HIV C. Indeterminate D. Further testing needed

B These results are not indicative of an HIV infection and may be due to a testing error in the first ELISA assay. Known false-positive ELISA reactions occur in autoimmune diseases, syphilis, alcoholism, and lymphoproliferative diseases. A sample is considered positive for HIV if it is repeatedly positive by ELISA or other screening method and positive by a confirmatory method. Harr, Robert R. Medical Laboratory Science Review (Page 90). F.A. Davis Company. Kindle Edition.

A physician orders 2 units of leukocyte-reduced red blood cells. The patient is a 55-year-old male with anemia. He types as an AB negative, and his antibody screen is negative. There is only 1 unit of AB negative in invetory. What is the next blood type that should be given? A. AB positive (patient is male) B. A negative C. B negative D. O negative

B While giving Rh-positive RBCs to an Rh-negative patient would not harm the patient in this case, because he is male, giving A negative would be the first choice. You should not expose a patient to the D antigen, if possible, and the residual anti-B in a unit of A-negative packed cells is less immunogenic than giving B or O red cells. Harr, Robert R. Medical Laboratory Science Review (Page 133). F.A. Davis Company. Kindle Edition.

An immunosuppressed patient has an unexplained anemia. The physician suspects a parovirus B19 infection. A parovirus IgM teset is negative. The next course of action is to tell the physician: A. The patient does not have parovirus B. A convalescent specimen is recommended in 4 weeks to determine if a fourfold rise in titer has occurred C. A parovirus PCR is recommended D. That a recent transfusion for the patient's anemia may have resulted in a false-negative assay and the patient should be retested in 4 weeks

C A negative IgM assay rarely rules out an infection. While a convalescent specimen may be useful in many cases, in an immunosuppressed patient the convalescent specimen may remain negative in the presence of an infection. Thus a parvovirus PCR test is the preferred choice in this case. A false-negative result could conceivably be caused by multiple whole blood or plasma transfusions, but retesting for antibody a month later would not be beneficial to the patient. Harr, Robert R. Medical Laboratory Science Review (Page 98). F.A. Davis Company. Kindle Edition.

A stem cell transplant patient was retyped when she was transferred form another hospital. What is the most likely cause of the following results? Patient cells: Anti-A negative, Anti-B 4+ Patient serum: A1 cells negative, B cells negative A. Viral infection B. Allantibodies C. Immunodeficiency D. Autoimmune hemolytic anemia

C A transplant patient is probably taking immunosuppressive medication to increase graft survival. This can contribute to the loss of normal blood group antibodies as well as other types of antibodies. Harr, Robert R. Medical Laboratory Science Review (Page 128). F.A. Davis Company. Kindle Edition.

What would be the most likely designation by the WHO for the FAB AML M7 by the French-American-British classification? A. Acute myeloid leukemias with recurrent genetic abnormalities B. Acute myeloid leukemia with multilineage dysplasia C. Acute myeloid leukemia not otherwisde categorized D. Acute leukemias of ambiguous lineage

C Acute megakaryoblastic leukemia, which is equivalent to FAB M7, is a relatively uncommon form of leukemia characterized by neoplastic proliferation of megakaryoblasts and atypical megakaryocytes. Recognition of this entity was aided by the use of platelet peroxidase (PPO) ultrastructural studies. PPO, which is distinct from myeloperoxidase, is specific for the megakaryocytic cell line. Acute megakaryoblastic leukemia is defined as an acute leukemia in which greater than or equal to 50% of the blasts are of megakaryocytic lineage. Harr, Robert R. Medical Laboratory Science Review (Page 25). F.A. Davis Company. Kindle Edition.

Interpret the following results for EBV infection: IgG and IgM antibodies to viral capsid antigen (VCA) are positive. A. Infection in the past B. Infection with a mutual enhancer virus such as HIV C. Current infection D. Impossible to interpret; need more information

C Antibodies to both IgG and IgM VCA are found in a current infection with EBV. The IgG antibody may persist for life, but the IgM anti-VCA disappears within 4 months after the infection resolves. Harr, Robert R. Medical Laboratory Science Review (Page 94). F.A. Davis Company. Kindle Edition.

A prolonged APTT is corrected with factor VIII-deficient plasma but not with factor IX-deficient plasma. Which factor is deficient? A. V B. VIII C. IX D. X

C Because the prolonged APTT is not corrected with a factor IX-deficient plasma, factor IX is suspected to be deficient in the test plasma. Harr, Robert R. Medical Laboratory Science Review (Page 53). F.A. Davis Company. Kindle Edition.

Bernard-Soulier syndrome is associated with: A. Decreased bleeding time B. Decreased factor VIII assay C. Thrombocytopenia and giant platelets D. Abnormal platelet aggregation to ADP

C Bernard-Soulier syndrome is associated with thrombocytopenia and giant platelets. It is a qualitative platelet disorder caused by the deficiency of glycoprotein Ib. In Bernard-Soulier syndrome, platelet aggregation to ADP is normal. Aggregation in the platelet function assay is abnormal. Factor VIII assay is not indicated for this diagnosis. Harr, Robert R. Medical Laboratory Science Review (Page 48). F.A. Davis Company. Kindle Edition.

A patient's serum is incompatible with O cells. The patient RBCs give a negative reaction to anti-H lectin. What is the most likely cause of these results? A. The patient may be a subgroup of A B. The patient may have an immunodeficiency C. The patient may be a Bombay D. The patient may have developed alloantibodies

C Bombay is the only ABO phenotype incompatible with O cells. The red cells of a Bombay show a negative reaction to anti-H because the cells contain no H substance. Harr, Robert R. Medical Laboratory Science Review (Page 126). F.A. Davis Company. Kindle Edition.

A carbohydrate antigen 125 assay (CA-125) was performed on a woman with ovarian cancer. After treatment, the levels fell significantly. An examination performed later revealed the recurrence of the tumor, but the CA 125 levels remained low. How can this finding be explained? A. Test error B. CA-125 was the wrong laboratory test; alpha-fetoprotein (AFP) is a better test to monitor ovarian cancer C. CA-125 may not be sensitive enough when used alone to monitor tumor development D. CA-125 is not specific enough to detect only one type of tumor

C CA-125 is a tumor associated carbohydrate antigen that is elevated in 70%-80% of patients with ovarian cancer and about 20% of patients with pancreatic cancer. While an increase in CA-125 may indicate recurrent or progressive disease, failure to do so does not necessarily indicate the absence of tumor growth. Harr, Robert R. Medical Laboratory Science Review (Page 109). F.A. Davis Company. Kindle Edition.

All positive cold agglutinin tubes remain positive after 37 degrees Celsius incubation except the positive control. What is the most likely explanation for this situation? A. High titer cold agglutinins B. Contamination of the test system C. Antibody other than cold agglutinins D. Faulty water bath

C Cold agglutinins do not remain reactive above 30°C, and agglutination must disperse following incubation at 37°C. The most likely explanation when agglutination remains after 37°C incubation is that a warm alloantibody or autoantibody is present. Harr, Robert R. Medical Laboratory Science Review (Page 96). F.A. Davis Company. Kindle Edition.

Which condition would most likely be responsible for the following typing results? Patient cells: Anti-A negative, Anti-B negative Patient serum: A1 cells negative, B cells 4+ A. Immunodeficiency B. Masking of antigens by the presence of massive amounts of antibody C. Weak or excessive antigen(s) D. Impossible to determine

C Excessive A substance, such as may be found in some types of tumors, may be neutralizing the anti-A. Weak A subgroups may fail to react with anti-A and require additional testing techniques (e.g., room-temperature incubation) before their expression is apparent. Harr, Robert R. Medical Laboratory Science Review (Page 128). F.A. Davis Company. Kindle Edition.

Which set of platelet responses would be most likely associated with Glanzmann's thrombasthenia? A. Normal platelet aggregation to ADP and risotcetin; decreased aggregation to collagen B. Normal platelet aggregation to collagen; decreased aggregation to ADP and ristocetin C. Normal platelet aggregation to ristocetin; decreased aggregation to collagen, ADP, and epinepherine D. Normal platelet aggregation to ADP; decreased aggregation to collagen and ristocetin

C Glanzmann's thrombasthenia is a disorder of platelet aggregation. Platelet aggregation is normal in response to ristocetin, but abnormal in response to collagen, ADP, and epinephrine. Harr, Robert R. Medical Laboratory Science Review (Page 49). F.A. Davis Company. Kindle Edition.

Refer to the following results: PT = prolonged APTT = prolonged Platelet count = decreased Which disorder may be indicated? A. Factor VIII deficiency B. von Willebrand's disease C. DIC D. Factor IX deficiency

C In DIC, there is a diffuse intravascular generation of thrombin and fibrin. As a result, coagulation factors and platelets are consumed, resulting in decreased platelet count and increased PT and APTT. Harr, Robert R. Medical Laboratory Science Review (Page 54). F.A. Davis Company. Kindle Edition.

Mrs. Smith has the following laboratory results, and no bleeding history: APTT: prolonged APTT results on a 1:1 mixture of the patient's plasma with normal plasma: Preincubation: prolonged APTT 2-hour incubation: prolonged APTT These results are consistent with: A. Factor VIII deficiency B. Factor VIII inhibitor C. Lupus anticoagulant D. Protein C deficiency

C Mixing studies differentiate factor deficiencies from factor inhibitors. Lupus anticoagulant is associated with thrombosis, and it is directed against phospholipid-dependent coagulation tests such as the APTT. In patients with lupus anticoagulant, the APTT after mixing patient's plasma with normal plasma remains prolonged immediately after mixing and following 2-hours incubation. Factor VIII deficiency and factor VIII inhibitor are associated with bleeding. Factor VIII inhibitor is time and temperature dependent. The prolonged APTT may be corrected immediately after mixing, and becomes prolonged following incubation. In factor VIII deficiency, the prolonged APTT would be corrected after mixing the patient's plasma with normal plasma. Harr, Robert R. Medical Laboratory Science Review (Page 64). F.A. Davis Company. Kindle Edition.

Several hours after birth, a baby boy develops petechiae and purpura and a hemorrhagic diathesis. The platelet count is 18 x 10^&9/L. What is the most likely explanation for the low platelet count? A. Drug-induced thrombocytopenia B. Secondary thrombocytopenia C. Neonatal alloimmune thrombocytopenia D. Neonatal DIC

C Neonatal alloimmune thrombocytopenia is similar to the hemolytic disease of the fetus and newborn. It results from immunization of the mother by fetal platelet antigens. The offending antibodies are commonly anti HPA-1a alloantibodies that are directed against glycoproteins IIb/IIIa, Ib/IX, Ia/IIb, and CD 109. The maternal antibodies cross the placenta, resulting in thrombocytopenia in the fetus. Harr, Robert R. Medical Laboratory Science Review (Page 49). F.A. Davis Company. Kindle Edition.

In myeloid cells, the stain that selectively identifies phospholipid in the membranes of both primary and secondary granules is: A. PAS B. Myeloperoxidase C. Sudan Black B stain D. Terminal deoxynucleotidyl transferase (TdT)

C Phospholipids, neutral fats, and sterols are stained by Sudan Black B. The PAS reaction stains intracellular glycogen. Myeloperoxidase is an enzyme present in the primary granules of myeloid cells and to a lesser degree in monocytic cells. Terminal deoxynucleotidyl transferase is a DNA polymerase found in thymusderived and some bone marrow-derived lymphocytes. Harr, Robert R. Medical Laboratory Science Review (Page 23). F.A. Davis Company. Kindle Edition.

Given the following values, which set of red blood cell indices suggests spherocytosis? A. MCV 76 micrometers^3; MCH 19.9 pg; MCHC 28.5% B. MCV 90 micrometers^3; MCH 30.5 pg; MCHC 32.5% C. MCV 80 micrometers^3; MCH 36.5 pg; MCHC 39.0% D. MCV 81 micrometers^3; MCH 29.0%; MCHC 34.8%

C Spherocytes have a decreased cell diameter and volume, which results in loss of central pallor and discoid shape. The index most affected is the MCHC, usually being in excess of 36%. Harr, Robert R. Medical Laboratory Science Review (Page 7). F.A. Davis Company. Kindle Edition.

Diagnosis of lupus anticoagulant is confirmed by which of the following criteria? A. Decreased APTT B. Correction of the APPT by mixing studies C. Neutralization of the antibody by high concentration of platelets D. Confirmation that abnormal coagulation tests are time and temperature dependent

C The International Society of Hemostasis and Thrombosis has recommended four criteria for the diagnosis of lupus anticoagulant: (1) a prolongation of one or more of the phospholipid-dependent clotting tests such as APTT or DRVVT; (2) the presence of an inhibitor confirmed by mixing studies (not corrected); (3) evidence that the inhibitor is directed against phospholipids by neutralizing the antibodies with a high concentration of platelets (platelet neutralization test or DRVVT with platelet-rich plasma); (4) lack of any other causes for thrombosis. Lupus inhibitor is not commonly time or temperature dependent. Harr, Robert R. Medical Laboratory Science Review (Page 59). F.A. Davis Company. Kindle Edition.

A patient has a Hct of 30%, a hemoglobin of 8 g/dL, and an RBC count of 4.0 x 10^12 L. What is the morphological classification of this anemia? A. Normocytic normochromic B. Macrocytic hypochromic C. Microcytic hypochromic D. Normocytic hyperchromic

C The indices will provide a morphological classification of this anemia. The MCV is 75 fL (reference range 80-100 fL), the MCH is 20.0 pg (reference range 27-31 pg), and the MCHC is 26.6% (reference range 32%-36%). Therefore, the anemia is microcytic hypochromic. Harr, Robert R. Medical Laboratory Science Review (Page 15). F.A. Davis Company. Kindle Edition.

Blood is crossmatched on an A positive person with a negative antibody screen. The patient received a transfusion of A positive RBCs 3 years ago. The donors chosen for crossmatch were A positive. The crossmatch was run on the Ortho Provue and yielded 3+ incompatibility. How can these results be explained? A. The patient has an antibody to a low-frequency antigen B. The patient has an antibody to a high-frequency antigen C. The patient is an A2 with anti-A1 D. The patient is an A1 with anti-A2

C The patient is likely an A2 with anti-A1 which is causing reactivity in the crossmatch. A negative antibody screen rules out the possibility of an antibody to a high-frequency antigen, and two donor units incompatible rules out an antibody to a low-frequency antigen. Harr, Robert R. Medical Laboratory Science Review (Page 126). F.A. Davis Company. Kindle Edition.

What is the most likely explanation when a patient has clinical signs of viral hepatitis but tests negative for hepatitis A IgM, hepatitis B surface antigen, and hepatitis C Ab? A. Tests were performed improperly B. The patient does not have hepatitis C. The patient may be in the "core window" D. Clinical evaluation was performed improperly

C The patient may be in the "core window," the period of hepatitis B infection when both the surface antigen and surface antibody are undetectable. The IgM anti-hepatitis B core and the anti-hepatitis B core total antibody assays would be the only detectable markers in the serum of a patient in the core window phase of hepatitis B infection. Harr, Robert R. Medical Laboratory Science Review (Page 93). F.A. Davis Company. Kindle Edition.

Which of the following results is most likely discrepant? Anti-A negative, A1 cells negative, Anti-B 4+, B cells negative A. Negative B cells B. Positive reaction with anti-B C. Negative A1 cells D. No problem with this typing

C The reverse typing should agree with the forward typing in this result. The 4+ reaction with anti-B indicates group B. A positive reaction is expected with A1 cells in the reverse group. Harr, Robert R. Medical Laboratory Science Review (Page 128). F.A. Davis Company. Kindle Edition.

A patient's peripheral smear reveals numerous NRBCs, marked variation of red cell morphology, and pronounced polychromasia. In addition to a decreased Hgb and decreased Hct values, what other CBC parameters may be anticipated? A. Reduced platelets B. Increased MCHC C. Increased MCV D. Decreased red-cell distribution width (RDW)

C This patient's abnormal peripheral smear indicates marked red cell regeneration, causing many reticulocytes to be released from the marrow. Because reticulocytes are larger than mature RBCs, the MCV will be slightly elevated. Harr, Robert R. Medical Laboratory Science Review (Page 13). F.A. Davis Company. Kindle Edition.

Refer to the following results: PT = normal APTT = prolonged Bleeding time = increased Platelet count = normal Platelet aggregation to ristocetin = abnormal Which of the following disorders may be indicated? A. Factor VIII deficiency B. DIC C. von Willebrand's disease D. Factor IX deficiency

C VWF is involved in both platelet adhesion and coagulation via complexing with factor VIII. Therefore, in von Willebrand's disease (deficiency or functional abnormality of VWF) factor VIII is also decreased, causing an abnormal APTT as well as abnormal platelet aggregation to ristocetin. The platelet count and the PT are not affected in VWF deficiency. Harr, Robert R. Medical Laboratory Science Review (Page 55). F.A. Davis Company. Kindle Edition.

Which of the following test results is normal in a patient with classic von Willebrand's disease? A. Bleeding time B. Activated partial thromboplastin time C. Platelet count D. Factor VIII:C and von Willebrand's factor (VWF) levels

C Von Willebrand's disease is an inherited, qualitative platelet disorder resulting in increased bleeding, prolonged APTT, and decreased factor VIII:C and VWF levels. The platelet count and morphology are generally normal in von Willebrand's disease, but aggregation in the platelet function assay is abnormal. Harr, Robert R. Medical Laboratory Science Review (Page 48). F.A. Davis Company. Kindle Edition.

What is the correct procedure upon receipt of a test request for human chorionic gonadotropin (hCG) on the serum from a 60-year-old man? A. Return the request; hCG is not performed on men B. Perform a qualitative hCG test to see if hCG is present C. Perform the test; hCG may be increased in testicular tumors D. Perform the test but use different standards and controls

C hCG is normally tested for in pregnancy; it is increased in approximately 60% of patients with testicular tumors and a lower percentage of those with ovarian, GI, breast, and pulmonary tumors. Malignant cells secreting hCG may produce only the β-subunit; therefore, qualitative and quantitative tests that detect only intact hormone may not be appropriate. Harr, Robert R. Medical Laboratory Science Review (Page 109). F.A. Davis Company. Kindle Edition.

The detection of precipitation reactions depends on the presence of optimal proportions of antigen and antibody. A patient's sample contains a large amount of antibody, but the reaction in a test system containing antigen is negative. What has happened? A. Performance error B. Low specificity C. A shift in the zone of equivalence D. Prozone phenomenon

D Although performance error and low specificity should be considered, if a test system fails to yield the expected reaction, excessive antibody preventing a precipitation reaction is usually the cause. Prozone occurs when antibody molecules saturate the antigen sites, preventing cross linking of the antigen-antibody complexes by other antibody molecules. Because the antigen and antibody do not react at equivalence, a visible product is not formed, leading to a false-negative result. Harr, Robert R. Medical Laboratory Science Review (Page 83). F.A. Davis Company. Kindle Edition.

What corrective action should be taken when an indeterminate pattern occurs in an indirect IFA? A. Repeat the test using a larger volume of sample B. Call the physician C. Have another medical laboratory scientist read the slide D. Dilute the sample and retest

D An unexpected pattern may indicate the presence of more than one antibody. Diluting the sample may help to clearly show the antibody specificities, if they are found in different titers. If the pattern is still atypical, a new sample should be collected and the test repeated. Harr, Robert R. Medical Laboratory Science Review (Page 86). F.A. Davis Company. Kindle Edition.

Which of the following occurs in idiopathic myelofibrosis (IMF)? A. Myeloid metaplasia B. Leukoerythroblastosis C. Fibrosis of the bone marrow D. All of these options

D Anemia, fibrosis, myeloid metaplasia, thrombocytosis, and leukoerythroblastosis occur in idiopathic myelofibrosis. Harr, Robert R. Medical Laboratory Science Review (Page 27). F.A. Davis Company. Kindle Edition.

Autoagglutination of red cells at room temperature can cause which of the following abnormal test results? A. Low RBC count B. High MCV C. Low hematocrit D. All of these options

D Autoagglutination at room temperature may cause a low RBC count and high MCV from an electronic counter. The Hct will be low because it is calculated from the RBC count. Low RBC count and low Hct cause falsely high calculations of MCH and MCHC, respectively. Harr, Robert R. Medical Laboratory Science Review (Page 8). F.A. Davis Company. Kindle Edition.

Which of the following is (are) commonly found in CML? A. Many teardrop-shaped cells B. Intense LAP staining C. A decrease in granulocytes D. An increase in basophils

D CML is marked by an elevated WBC count demonstrating various stages of maturation, hypermetabolism, and a minimal LAP staining. An increase in basophils and eosinophils is a common finding. Pseudo-Pelger-Huët cells and thrombocytosis may be present. The marrow is hypercellular with a high M:E ratio (e.g., 10:1). Harr, Robert R. Medical Laboratory Science Review (Page 28). F.A. Davis Company. Kindle Edition.

Your cytology laboratory refers a Papanicolaou smear specimen to you for an assay designed to detect the presence of a virus associated with cervical cancer. You perform: A. An ELISA assay for anti-HSV-2 antibodies B. A molecular assay for HSV-2 C. An ELISA assay for an HPV antibodies D. A molecular assay for HPV

D Cervical cell atypia and cervical cancer are associated with specific high-risk serotypes of human papilloma virus (HPV) infections. Although HPV antibody assays are available, they are not serotype specific, nor do they relate to disease activity. Thus molecular probe assays are the tests of choice to detect high-risk HPV infection. Although HSV-2 is associated with genital herpesvirus, that virus has not been shown to cause cervical cancer. Harr, Robert R. Medical Laboratory Science Review (Page 98). F.A. Davis Company. Kindle Edition.

All tubes (dilutions) except the negative control are positive for cold agglutinins. This indicates: A. Contaminated red cells B. A rare antibody against red cell antigens C. The sample was stored at 4 degrees Celsius prior to separating serum and cells D. Further serial dilution is necessary

D Cold agglutinins may be measured in patients who have cold agglutinin disease, a cold autoimmune hemolytic anemia. In such cases, titers can be as high as 10 6. If all tubes (dilutions) for cold agglutinins are positive, except the negative control, then a high titer of cold agglutinins is present in the sample. Further serial dilutions should be performed. Harr, Robert R. Medical Laboratory Science Review (Page 96). F.A. Davis Company. Kindle Edition.

Which of the following laboratory tests is helpful in the diagnosis of aspirin resistance? A. APTT B. PT C. Platelet count and morphology D. Platelet aggregation

D Currently, the platelet aggregation test is considered the gold standard for evaluation of aspirin resistance. In aspirin resistance, platelet aggregation is not inhibited by aspirin ingestion. Aspirin resistance has no effect on platelet count and morphology. Harr, Robert R. Medical Laboratory Science Review (Page 61). F.A. Davis Company. Kindle Edition.

A 50-year-old man has been on heparin for the past 7 days. Which combination of the tests is expected to be abnormal? A. PT and APTT only B. APTT, TT only C. APTT, TT, fibrinogen assay D. PT, APTT, TT

D Heparin is a therapeutic anticoagulant with an antithrombin activity. Heparin also inhibits factors XIIa, XIa, Xa, and IXa. In patients receiving heparin therapy, the PT, APTT, and TT are all prolonged. Quantitative fibrinogen assay, however, is not affected by heparin therapy. Harr, Robert R. Medical Laboratory Science Review (Page 58). F.A. Davis Company. Kindle Edition.

A 61-year-old male with a history of multiple myeloma had a stem cell transplant 3 years ago. The donor was O positive and the recipient was B positive. He admitted to a community hospital for fatigue and nausea. Typing results reveal the following: Anti-A = 0 Anti-B = 0 Anti-A,B = 0 Anti-D = 4+ A1 cells =4+ B cells = 0 How would report this type? A. O positive B. B positive C. A positive D. Undetermined

D In a transplant scenario, there are no methods to employ to solve the discrepancy. The technologist must rely on the patient history of donor type and recipient type, and the present serological picture. A B-positive recipient given an O-positive transplant constitutes a minor ABO mismatch. The forward type resembles the donor. The reverse type still resembles the recipient. The ABO type reported out does not fit a pattern resulting in an undetermined type. Harr, Robert R. Medical Laboratory Science Review (Page 129). F.A. Davis Company. Kindle Edition.

Iron deficiency anemia may be distinguished from anemia of chronic infection by: A. Serum iron level B. Red cell morphology C. Red cell indices D. Total iron-binding capacity

D In iron deficiency anemia, the serum iron and ferritin levels are decreased and the total iron-binding capacity and RBC protoporphyrin are increased. In chronic disease, serum iron and TIBC are both decreased because the iron is trapped in reticuloendothelial (RE) cells, and is unavailable to the red cells for hemoglobin production. Harr, Robert R. Medical Laboratory Science Review (Page 14). F.A. Davis Company. Kindle Edition.

All of the following are characteristic findings in a patient with iron deficiency anemia except: A. Microcytic, hypochromic red cell morphology B. Decreased serum iron and ferritin levels C. Decreased total iron-binding capacity (TIBC) D. Increased RBC protoporphyrin

D Sideroblastic anemia has a decreased red cell protoporphyrin. The defect in sideroblastic anemia involves ineffective erythropoiesis. The failure to produce RBC protoporphyrin occurs because the nonheme iron is trapped in the mitochondria and is unavailable to be recycled. Harr, Robert R. Medical Laboratory Science Review (Page 15). F.A. Davis Company. Kindle Edition.

The JAK2(V617F) mutation may be positive in all of the following chronic myeloproliferative disorders except: A. Essential thrombocythemia B. Idiopathic myelofibrosis C. PV D. CML

D The JAK2(V617F) mutation is negative in patients with CML. It may be positive in patients with idiopathic myelofibrosis (35%-57%), polycythemia vera (65%-97%), and essential thrombocythemia (23%-57%). Harr, Robert R. Medical Laboratory Science Review (Page 30). F.A. Davis Company. Kindle Edition.

All of the following are major criteria for the 2008 WHO diagnostic criteria for essential thrombocythemia except: A. Platelet count >450 x 10^9/L B. Megakaryocyte proliferation with large and mature morphology, and no or little granulocyte or erythrocyte proliferation C. Demonstration of JAK(V617F) or other clonal marker D. Sustained platelet count >600 x 10^9/L

D The criterion for the 2001 WHO diagnosis of essential thrombocythemia (ET) was a platelet count ≥600 x 10 9/L. This was changed in the 2008 WHO criteria to ≥450 x 10 9 /L. Diagnosis of essential thrombocythemia requires meeting all four major 2008 WHO diagnostic criteria, which also includes: megakaryocyte proliferation with large and mature morphology and no or little granulocyte or erythroid proliferation; not meeting WHO criteria for CML, PV, IMF, MDS, or other myeloid neoplasm; and demonstration of JAK2(V617F) mutation or other clonal marker, or no evidence of reactive thrombocytosis. Harr, Robert R. Medical Laboratory Science Review (Page 30). F.A. Davis Company. Kindle Edition.

A 12-year old girl has symptoms of fatigue and a localized lymphadenopathy. Laboratory tests reveal a peripheral blood lymphocytosis, a positive RPR, and a positive spot test for IM. What test should be performed next? A. HIV test by ELISA B. VDRL C. Epstein-Barr virus (EBV) specific antigen test D. Treponema pallidum particle agglutination (TP-PA) test

D The patient's symptoms are nonspecific and could be attributed to many potential causes. However, the patient's age, lymphocytosis, and serological results point to infectious mononucleosis (IM). The rapid spot test for antibodies seen in IM is highly specific. The EBV-specific antigen test is more sensitive but is unnecessary when the spot test is positive. HIV infection is uncommon at this age and is often associated with generalized lymphadenopathy and a normal or reduced total lymphocyte count. IM antibodies are commonly implicated as a cause of biological false-positive nontreponemal tests for syphilis. Therefore, a treponemal test for syphilis should be performed to document this phenomenon in this case. Harr, Robert R. Medical Laboratory Science Review (Page 89). F.A. Davis Company. Kindle Edition.

The absorbance of a sample measured by ELISA is greater than the highest standard. What corrective action should be taken? A. Extrapolate an estimated value from the highest reading B. Repeat the test using a standard of higher concentration C. Repeat the assay using one half the volume of the sample D. Dilute the test sample

D Usually when a test sample reads at a value above the highest standard in an ELISA test, it is diluted and measured again. In those instances where no additional clinical value can be obtained by dilution, the result may be reported as greater than the highest standard (citing the upper reportable limit of the assay). Harr, Robert R. Medical Laboratory Science Review (Page 84). F.A. Davis Company. Kindle Edition.