media lab exam

In the Kleihauer-Betke test, a maternal blood smear is treated with acid and then stained with counterstain. The fetal cells contain fetal hemoglobin, which is resistant to acid and will remain pink. Since the calculated volume of fetomaternal hemorrhage is an estimate, how many additional RhIg vials need to be added for the dose?

1 After 2000 cells are counted, the percentage of fetal cells is determined, and the volume of fetal hemorrhage is calculated by the formula: number of fetal cells X maternal blood volume / number of maternal cells = volume of fetomaternal hemorrhage. Because the Kleihauer-Betke is an estimate, one vial is added to the calculated answer.

What is the acceptable temperature range for maintaining red blood cell components during transport?

1 - 10ºC Red blood cell components must be maintained between 1 - 10°C during shipping. Red blood cell components (with the exception of frozen RBC units) are stored refrigerated between 1 - 6ºC. Platelets must be transported in a temperature range between 20 - 24ºC or as closely as possible. The temperature range of 10 - 15ºC is not approved for storage or transport of blood components.

The primary antibody response takes an average of how many days?

14-21 days

Sequence-based analysis is an alternate method used to identify bacteria and fungal isolates. This methodology uses rRNA genes (rDNA) and their intergenic regions as common target sites to identify these organisms. Which of the following rRNA gene target sites is used to identify bacterial isolates?

16S rRNA 16S rRNA is the correct answer. The bacterial subunit 16S rRNA is encoded by a 1500 bp gene. Amplification of the first 500 base pairs is sufficient for the identification of most bacteria including anaerobes and mycobacteria organisms. 28S rRNA is incorrect because this subunit is used to identify fungal organisms. Within the 28S rRNA gene, there are D1/D2 regions that are commonly used as target sites to identify fungi. 25S rRNA and 14S rRNA are both incorrect answers as these are not target regions used to identify bacteria and fungal isolates.

A 4.0 mg/dL creatinine standard is needed. To prepare 100 mL of the working standard, how much stock standard of 1 mg/mL creatinine is needed?

4 mL

Which one of the following antibodies has been implicated in hemolytic disease of the fetus and newborn (HDFN)?

Anti-K

Identify the urine sediment elements indicated by the arrow in the illustration:

Cholesterol crystals

What is the nucleated cell called?

Neutrophil

Which of the following statements regarding peak level in therapeutic drug monitoring is true?

Peak level is assessed by collecting a blood sample after a dose of the drug is given (at a specified time).

In reference to semen analysis microscopic examination, differentiation and enumeration of "round cells" which are often present in semen count are refered as:

White blood cells (WBCs) Round cells refer to WBCs or immature sperm cells in a semen sample. These cells can be differentiated on a stained smear, using 1000X magnification, or more precisely by performing a peroxidase assay. An increased number of WBCs present indicates inflammatory conditions associated with infection and poor sperm quality. Sperm vitality and seminal fluid fructose are the types of additional testing done when abnormalities suspected in sperm morphology and functionality. The presence of Bacteria in seminal analysis may be indicative of an infection

When should acute and convalescent blood specimens be collected from a patient for the detection of antibody concentration related to a specific infectious disease?

2 weeks apart In obtaining specimens for serologic testing, it is important to consider the phase of the disease and the condition of the patient at the time of specimen collection. This is especially important in assays for the diagnosis of infectious diseases. If patient serum is being tested for the concentration (titer) of antibodies for a specific infectious organism, a blood specimen should be drawn and the serum frozen during the acute phase of the illness (when the disease is first discovered or suspected), and a second blood sample drawn during the convalescent phase, usually about 2 weeks later. A difference in the antibody titer may be noted when the two different samples are tested concurrently. In general, 4 weeks is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). In general, 3 months is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). In general, 6 months is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). However, some infectious diseases, such as Legionnaire's disease or hepatitis may not manifest a rise in titer until months after the acute infections.

The proper storage requirements for granulocyte concentrates is:

20 - 24 degrees Celsius, 24 hours Granulocytes are used as treatment for patients that are severely neutropenic (neutrophil count less than 500/µL) who have the following: Documented infection (24-48 hours) that is nonresponsive to antibiotic or antifungal treatment, myeloid hyperplasia demonstrated by bone marrow biopsy, and a chance of bone marrow recovery. Granulocytes are most often collected by apheresis to achieve a higher yield than those collected from whole blood. Storage is 20-24 degrees Celsius for up to 24 hours, but should be transfused as soon as possible. The other storage conditions above all have temperatures lower than what is optimal for granulocytes.

What should be added to the cytocentrifuge chamber when preparing slides on serous fluids to aid in adhesion of cells to the slide and preserve cellular morphology?

22% Albumin 10-22% Albumin should be added when preparing serous fluids and CSF. The addition of albumin helps preserve cellular morphology and improves adhesion to the slide. Hyaluronidase can be added to synovial fluids to help overcome the increased viscosity of these fluids during slide preparation. 10% acetic acid can be used as a diluent for grossly bloody serous fluids and CSF. The acetic acid lyses the red blood cells to increase the visualization of the nucleated cells present. Sterile saline can be used to make dilutions of fluids with red blood cell counts less than 5000 cells/mcL. This saline dilution also assists with the visualization of the nucleated cells present.

The recommended storage temperature for the preservation of activity for MOST enzymes is:

4ºC Refrigerated temperatures, those close to 4ºC, are recommended for the preservation of most enzyme activity in a patient sample. Repeated freezing and thawing should be avoided as this may denature the enzyme and inactivate its functions.

It's a busy Friday evening in the blood bank and you have been receiving a steady stream of Type & Screen specimens from the emergency room. Several of them have positive antibody screens which require further workup. One of these patients is a 46-year-old male whose hemoglobin has dropped from 8.4 g/dL to 4.6 g/dL in the previous 8 hours (normal Hgb for this patient demographic would be ~14 g/dL). Your workup reveals a group O patient with the following antibodies: anti-K, anti-Fya. The prevalence of K negative donors in your donor population is 91% while the prevalence of Fya negative donors is 37%. Two units of cross-matched RBCs are requested by the physician. How many units of group O RBC units should you phenotype in order to fulfill the request for two cross-matched units?

6 units of type O RBC units Based on the antigen prevalence information provided, you will need to test 6 units of group O RBC units in order to get 2 units of group O RBC units that are negative for both the K and Fya antigens. STEP 1: The percentage of donors negative for each antigen should be written in decimal points, and then multiplied: 0.91 (K negative) X 0.37 (Fya negative) = 0.33 STEP 2: Next, find the reciprocal of the number found in the first step. In other words, divide 1 by the number you calculated in the first step: 1/0.33 = 3 3 units should be antigen typed in order to find a single unit negative for both of these antigens. Remember - you need to crossmatch TWO units, so you would actually need to antigen type 6 units to find two that could be crossmatched. 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: 33/100 = 2/x 33x = 200 x = 6.06 or approximately 6 units

If possible, what is the recommended time interval for Rh immune globulin administration to the Rh negative mother following the delivery of an Rh positive or weak-D positive infant?

72 hours The Rh negative nonimmunized mother should receive RhIg soon after delivery of an Rh positive baby. Based on experiments conducted many years ago, the recommended interval is within 72 hours after delivery. Even if more than 72 hours have elapsed, RhIg should still be given, as it may be effective and is not contraindicated.

The statistics for a specific laboratory test method are illustrated to the right. What is the sensitivity of this test?

94% The correct answer is 94%. To calculate the sensitivity of this test, the values must be entered into the formula for sensitivity: (True positives / (True positives + False negatives) X 100) = Sensitivity (150 true positives) / (150 true positives + 10 false negatives) X 100 = 94%

A patient is group AB with one copy of the Se gene. What will they have in their secretions?

A, B, & H A, B, and H antigens are found on red blood cells but they can also be found in secretions if the individual has at least one copy of a secretor gene (Se). The Se gene codes for a transferase that modifies type I precursors in secretions to form H. Once H is formed, immunodominant sugars can be added to produce A and B antigens in secretions. In this question, AB patients who are secretors will have A, B, and H substances secreted. Group B patients who are secretors will have both B and H substances secreted. Group A patients who are secretors will have both A and H substances secreted. Group O secretors will only secrete H substance.

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

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.

Units of A-negative, B-negative, and O-negative red blood cells are shipped to your transfusion service. What testing MUST be performed by your facility prior to placing these units into your inventory?

ABO and Rh

An abnormality of which of the following assays would be LEAST likely to be associated with thrombotic tendency?

APTT

Which of the following analytes would be increased due to delay in centrifugation?

AST The specimen should not be delayed for more than two hours prior to centrifugation because some of the analyte levels (such as glucose, ionized calcium, bicarbonate, folate, etc.) may be falsely decreased due to cellular consumption or falsely increased (such as potassium, ALT, AST, creatinine, etc.) because they are released over time from cells into serum or plasma.

An 8-year-old boy presents with a 2 week history of high fevers and lethargy. He has shown petechiae and bleeding gums for approximately 3 weeks. Upon physical examination, the following was noted: Enlarged cervical lymph nodes, Pale and febrile, Enlarged spleen His laboratory results were the following: Hgb = 6.3g/dLHct = 18.9% RBC count = 2.89 x 109/L WBC Count = 96 x 109/L Platelet count = 23 x 109/L Differential: 90% blasts, 5% bands, 5% neutrophils BM aspirate > 90% blasts What is this patient most likely suffering from?

Acute leukemia A high white blood cell count with many blasts in the peripheral blood and bone marrow, along with a low platelet and RBC count are associated with acute leukemia. WHO classification of acute leukemia includes > 20% blasts in the bone marrow. There is an arrest in the maturation process of these malignant cells resulting in the accumulation of the immature cells. Further testing must be done to classify the exact subclass of acute leukemia. Given the patient's age, acute lymphoblastic leukemia is the most likely as ALL is the most common childhood leukemia. Polycythemia vera is a myeloproliferative disorder that usually presents with increased RBC count, granulocytes, and platelets. Median age is 60 years old. Chronic leukemias are characterized by leukocytosis and excessive proliferation of mature blood cells. There may be some immature cells present, but they are capable of maturation. Chronic leukemias are typically considered a disease of adults in their 50's or 60's. Infectious mononucleosis is a benign lymphoproliferative disorder caused the Epstein-Barr virus. Most patients present with a leukocytosis from 10 to 20 x 109/L. About 10% of individuals present with a leukopenia. Patients present with variant or reactive lymphocytes. These reactive lymphocytes present with a variety of sizes and shapes. Usually they are large with wandering cytoplasm that may be indented by the adjacent RBCs. The cytoplasm may be more basophilic at the periphery of the cell.

Red blood cells with a positive DAT cannot be tested accurately with blood typing reagents that require an indirect antiglobulin technique unless they have been treated with all of the following (to dissociate IgG from the RBC membrane) EXCEPT:

Albumin The correct answer is albumin. Albumin would not be an effective way to remove IgG bound to the RBC's so that further testing could be performed. Red blood cells with a positive DAT cannot be testws accurately with blood typing reagents that require an indirect antiglobulin technique unless they have been treated with chloroquine diphosphate, ZZAP, or ficin to dissociate IgG from the RBC membrane.

Which of the following tests is the BEST screening test for neural tube defects?

Alpha-fetoprotein Alpha-fetoprotein is produced by the fetal liver. It is measured in pregnant women, using maternal blood or amniotic fluid, as a screening test for a subset developmental abnormalities. Abnormally high levels of this substance is associated with defects in the fetal neural tube, while abnormally low levels are associated with the presence of Down' syndrome.

Which listed transfusion reaction is MOST OFTEN associated with transfused patient's lacking IgA?

Anaphylaxis Anaphylactoid and anaphylactic reactions (collectively referred to as anaphylaxis) result from the recipient's forming anti-IgA, which targets IgA proteins in the donor plasma. Recipients have a genetic IgA deficiency and have developed anti-IgA from sensitization during a previous transfusion or pregnancy. Patients experience IgA deficiency related anaphylactic reactions. Hemolytic reactions occur due to the presence of recipient autoantibodies or alloantibodies reacting with donor antigens. Febrile reactions are due to recipient white cell antibodies causing the release of pyrogens or to donor platelet release of cytokines. TACO occurs when the patient's cardiovascular system is unable to handle the additional volume from the transfusion and is manifested as congestive heart failure.

What is this form, measuring 45 µm and found in stool?

Ascaris lumbricoides egg This image shows a round egg with a distinct corticated outer shell, which is definitive for Ascaris lumbricoides. Balantidium coli cysts are round, but have a distinctive large, kidney-bean shaped macronucleus present in the cytoplasm. There can also be a visible micronucleus located adjacent to the macronucleus. Vacuoles can also be present. This image does not show a nucleus, so cysts and trophozoite forms can be ruled out. Schistosoma mansoni eggs can be distinguished by a large lateral spine present on the egg. They are also a much larger egg, ranging from 112 to 182 µm in size. Hymenolepis diminuta eggs do have a capsule around the embryo which can look similar to the Ascaris lumbricoides corticated shell, but Hymenolepis diminuta contains three pairs of hooks in the embryo that are distinguishable. Hymenolepis is also larger, typically 55 by 85 µm in size.

Fecal urobilinogen level may be markedly decreased because of:

Biliary obstruction In the intestines, bilirubin is converted to urobilinogen. Most urobilinogen, which gives feces their dark color, is excreted in the feces. An absence of bilirubin in the intestine, such as may occur with bile duct obstruction, blocks the conversion of bilirubin to urobilinogen, which causes clay-colored stools and a decreased fecal urobilinogen level.

What additional fraction would be seen if plasma rather than serum was subjected to electrophoresis:

Fibrinogen Fibrinogen is only found in plasma. It is absent in serum because it is consumed during the clotting process. Fibrinogen present in plasma would form a band between the beta and gamma globulins. Electrophoresis separates the serum proteins into four bands, which from the anodal end are: albumin, alpha, beta, and gamma globulins.

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:

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).

All of the following statements are characteristic of the role of C-reactive protein (CRP) except?

Binds with factor H to initiate alternate complement pathway. C-reactive protein, or CRP, can activate complement, exhibit pro-inflammatory characteristics, and initiates opsonization (phagocytosis enhancement). However, CRP does not actually bind with factor H to initiate the alternate complement pathway. CRP is one of the first acute-phase protein to rise as a result to inflammatory disease and is produced by the liver.

The hematology analyzer reported an elevated white blood cell count and flagged for manual review due to the suspected presence of immature cells. What is the arrowed cell's identity, and what name is given to its inclusion?

Blast with Auer rod The arrowed cell is a blast containing an Auer rod. Auer rods are red-purple in color. They are composed of fused primary granules. One or more Auer rods may be observed in the cytoplasm of myeloblasts. Myeloblasts have between 0-20 primary granules. Lymphoma cells are medium to large cells with blue cytoplasm that may or may not contain vacuoles. The chromatin is less condensed than resting B and T lymphocytes. Lymphoma cells are not frequently seen phagocytizing bacteria. Promyelocytes are often slightly larger than myeloblasts but they have fewer and less prominent nucleoli and slightly coarser chromatin. Promyelocytes have more than 20 primary granules. Döhle bodies are blue-gray in color. They are typically found in band and segmented neutrophils.

What is the primary function of hemoglobin?

Carry oxygen to tissues Hemoglobin serves to carry inspired oxygen from the lungs to tissues, and carbon dioxide from tissues back to the lungs, where it is expired. Iron is a part of functional hemoglobin, but it is not stored there.

When using a flow cytometer, forward scatter measures which of the following parameters?

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.

Which of the following is the bacterial agent associated with antibiotic-associated pseudomembranous colitis?

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.

Which of the following statements is true regarding the storage and handling of urinalysis chemical reagent strips?

Remove only enough strips for immediate use.

An elevated level of which of the following hormones will inhibit pituitary secretion of adrenocorticotropic hormone (ACTH)?

Cortisol Cortisol is part of the negative feedback mechanism for ACTH. So, elevated levels of cortisol stimulate the pituitary gland to inhibit the secretion of ACTH. The hypothalamic-pituitary-end organ negative feedback system that controls cortisol release follows the steps: Hypothalamus releases corticotropin-releasing hormone (CRH) which is delivered to the anterior pituitary. CRH triggers the release of ACTH by the anterior pituitary. Antidiuretic hormone (ADH) and proinflamatory cytokines can also independently trigger ACTH release. ACTH trigger the synthesis and release of cortisol from the adrenal glands. Increased cortisol levels feedback at the anterior pituitary (to stop ACTH release) and hypothalamus (to stop CRH) respectively. Hypothalamus is the major site of this negative feedback from cortisol.

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:

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'.

The measurement of sodium and chloride in sweat is the most useful test for the diagnosis of what condition/disease?

Cystic fibrosis

All of the following are characteristic findings in patients with iron deficiency anemia EXCEPT?

Decreased total iron-binding capacity (TIBC) Iron deficiency anemia, or IDA, is associated with an increased TIBC as there is less iron to bind to transferrin. Microcytic, hypochromic red cell morphology, a decreased serum iron level, a decreased serum ferritin level, and a decreased hemoglobin level are all characteristics associated with IDA.

Which of the following conditions is associated with a positive ketone test on the urine test strip?

Diabetes mellitus Findings of ketones on the urine test strip is associated with diabetes mellitus. A positive blood urine test strip reaction can be caused by renal calculi. Bilirubin in urine is associated with hepatitis/cirrhosis. A positive nitrite pad would be indicative of urinary tract infection.

What is defined as the ability of the test to detect a given disease or condition?

Diagnostic sensitivity Diagnostic sensitivity is the ability of a test to detect a given disease or condition. Positive predictive value is the chance an individual having a given disease or condition if the test is abnormal. Negative predictive value is the chance an individual does not have a given disease or condition if the test is within the reference interval. Diagnostic specificity is the ability of a test to correctly identify the absence of a given disease or condition.

When AHG or Coombs serum is used to demonstrate that red blood cells are antibody coated in vivo, the procedure is termed:

Direct technique The direct antiglobulin test (also known as "DAT") is performed to detect in vivo sensitization of RBCs with IgG or complement. In vivo coating of RBCs with IgG antibody or complement are associated with the following clinical conditions: autoimmune and drug-induced hemolytic anemia (AIHA), hemolytic disease of the fetus and newborn (HDFN), and hemolytic transfusion reaction (HTR). The indirect technique is performed to detect in vitro sensitization of RBCs for antibody screening and compatibility testing purposes. Both hemagglutination and hemolysis techniques are in vitro testing methods used for the detection of antigens or antibodies.

Which condition is caused by deficient secretion of bilirubin into the bile canaliculi?

Dubin-Johnson syndrome Dubin-Johnson syndrome is an autosomal recessive disorder that causes an increase of conjugated bilirubin without elevation of liver enzymes (ALT, AST). This condition is associated with a defect in the ability of hepatocytes to secrete conjugated bilirubin into the bile. Gilbert's syndrome causes an otherwise harmless jaundice, which does not require treatment, caused by hyperbilirubinemia. Neonatal hyperbilirubinemia is associated with jaundice and is a condition marked by high levels of bilirubin in the blood. Crigler-Najjar syndrome is associated with increased levels of bilirubin in the blood as the disorder affects the metabolism of bilirubin.

Treatment of "sequestration crisis," often seen in infants and young children with sickle cell disease, involves which of the following?

Exchange transfusions, and/or splenectomy. Treatment of sequestration crisis may include chronic transfusion, exchange transfusion, and/or splenectomy, depending on the patient's age and the severity of the sequestration (as determined by the hemoglobin level and degree of drop in hemoglobin). Sequestration crisis occurs in sickle cell disorders when large numbers of RBCs are suddenly pooled in the spleen and liver. These organs can enlarge rapidly causing pain, hypoxemia, and hypovolemic shock. Bone marrow transplant is successful to treat sickle cell disease for some individuals, but it is not used to treat sequestration crisis. Antibiotics are used to treat infections. Hydroxyurea relieves the disorder by increasing the proportion of Hb F.

The 20 mm mature adult fluke illustrated in the photograph has a normal habitat in the liver bile ducts. Humans become infected by ingesting raw or undercooked water plants contaminated with infective metacercaria. These adult flukes are only observed during surgery involving the liver or at autopsy. Intermittent upper abdominal discomfort and low grade jaundice may be experienced. From the multiple choices listed, select the presumptive identification of this fluke.

Fasciola hepatica The adult Fasciola hepatica is 20 - 30 mm in size and has a cone like cephalic protrusion. Anterior and ventral suckers are clearly visible. Being hermaphrophilic, it contains a short convoluted uterus observed anterior, and delicately branched testes located posterior. C. sinensis flukes are less than half the size (7 - 15 mm) and are bottle-shaped with a long protruding cephalic head. They contain highly visible, broad branched testes occupying the posterior part of the fluke from which the genus name clonorchis ("branched testes") is derived. F. buski flukes are large, measuring up to 70 mm long, and inhabit the small intestine, particularly the duodenum and jejunum. Distinctive is the rounded cephalic end rather than a cone-shaped anterior protrusion. Being hermaphrophilic, a convoluted branching anterior uterus and delicate branching testes is observed posteriorly. P. westermani flukes are relatively small (10 - 16 mm) with a flattened oval shape. One end is contracted and the other is the form of a broad smooth curve. Being hermaphrophilic, irregularly lobed testes lie oblique to one another in the posterior third of the adult fluke along side a lobed ovary and a closely coiled uterus lying anterior. Adult flukes primarily occupy the lungs.

Which of the following terms is used to describe the appearance of rod-shaped bacteria?

Filamentous When describing rod-shaped bacteria, the terms used may help to identify the type of bacteria present. Filamentous may describe the appearance of certain bacteria such as Nocardia. Other terms that might be used to describe bacilli include diphtheroid, pleomorphic, beaded, branched, bipolar, spiral, and fusiform. The term budding is frequently used to describe yeast, but not rod-shaped bacteria. Septate is a term that is applied to the description of hyphae. Lancet-shaped gram-positive diplococci are frequently seen microscopically with Streptococcus pneumoniae; however, lancet is not a term that is used to describe bacilli.

Which of the following is associated with macrocytic anemia?

Fish tapeworm The correct answer is fish tapeworm. Diphyllobothrium latum, also known as a fish tapeworm, can cause a deficiency of vitamin B12 as it accumulates the vitamin preferentially. A deficiency of vitamin B12 is a type of megaloblastic (macrocytic) anemia. Iron deficiency anemia is a microcytic, hypochromic anemia. Sickle cell disease is a normocytic, normochromic anemia. Beta thalassemia minor is a microcytic, hypochromic (sometimes normochromic) anemia.

The bone marrow begins producing cells in the _____________ month of fetal life.

Fourth

Illustrated in the upper image is a 4 day growth of a fungus colony on Sabouraud's dextrose agar. Note the cottony to woolly surface, and the distinctive lavender, pink pigmentation. The lower image is of a lactophenol cotton blue pigmented view of long, narrow multi-celled macro-conidia that are sickle-shaped. Based on these observations, select the genus identification of this isolate.

Fusarium Fusarium is the correct answer because colonies are distinctive for the lavender pink to reddish pigmentation. The production of long, sickle-shaped (canoe/banana) segmented macro-conidia is also distinctive. Identification of Fusarium species is important as infections may result in mycotic keratitis. Curvularia is incorrect because Curvularia produces black pigmented colonies. Upon microscopic examination, knobby conidiophores with boomerang-shaped conidia containing four cells can be seen. Acremonium is incorrect because colonies are gray to light shades of yellow with a smooth surface. Small spherical to club-shaped 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. Acremonium can resemble Fusarium, but Acremonium produces septate hyphae with fine and narrow phialides that produce oval conidia. Paecilomyces is incorrect even though they can produce pink to lilac colonies. Microscopically, the colonies will demonstrate septate, hyaline hyphae with branching conidiophores that have long, slender, tapered phialides. The conidia will be oval shaped in chains.

The following urine test results were obtained from a 6-month-old African American infant who experiences vomiting and diarrhea after milk ingestion and has failed to gain weight: pH: 5.0Protein: NegativeGlucose: NegativeKetones: NegativeBlood: NegativeBilirubin: NegativeNitrite: NegativeUrobilinogen: 0.1 EU/dLClinitest: 2+ These results are clinically significant in which of the following disorders?

Galactosemia Galactosemia is an inherited metabolic disorder that affects an individual's ability to metabolize the sugar galactose effectively. Infants affected by galactosemia typically present with symptoms of lethargy, vomiting, diarrhea, failure to thrive, and jaundice. The presence of galactose in the urine sample is not picked up by the glucose pad on the urine test strip. However, the Clinitest result is positive since it can detect different sugars in the urine, including galactose, therefore diabetes mellitus would not be suspected for this patient. Cystic fibrosis would not be associated with the findings in this case. In addition, the clinical symptoms and patient age differentiates lactose intolerance from galactosemia. True lactose intolerance will usually not become symptomatic in children until they are at least 3 years old (usually after age 7). Also, lactose intolerance is associated with diarrhea, but not closely associated with vomiting.

A Basic Metabolic Panel (BMP) consists of which group of tests?

Glucose, BUN, Creatinine, Sodium, Potassium, Chloride, CO2, Calcium The Basic Metabolic Panel consists of Glucose, BUN, Creatinine, Sodium, Potassium, Chloride, CO2, Calcium. The Hepatic Function Panel A consists of AST, ALT, Alkaline Phosphatase, Total Protein, Albumin, Total Bilirubin, Direct Bilirubin. The Lipid Panel consists of Cholesterol, Lipoprotein, HDL, Triglycerides. The Electrolyte Panel consists of potassium, sodium, chloride, carbon dioxide. These analytes are also typically ordered within other panels as well, including the basic metabolic and complete metabolic panels.

This organism has been placed in trypticase soy broth and then streaked on a nutrient agar plate. Strips containing X, V, and XV were place on the plate and it was incubated 24 hours in CO2 conditions. With this information and the picture to the right, what is the identification of this organism?

Haemophilus influenzae The correct answer is Haemophilus influenzae . Haemophilus influenzae requires both X (hemin) and V factors (nicotinomide adenine dinucleotide-NAD) to grow. H.influenzae typically causes infections of the lower respiratory tract in patients with chronic respiratory ailments and meningitis in children less than two years of age. Brucella abortus does not require X or V factor. It is a slow-growing, faintly staining, tiny coccobacillus. Haemophilus parainfluenzae does require V factor, but not X factor. Colonies look similar to those of H.influenzae, but they appear smaller and have a matte appearance. Pasteurella multocida does not require X or V factor and will grow on both sheep blood agar (SBA) and chocolate agar.

All of the following diseases are associated with autoantibodies, EXCEPT?

Hemolytic disease of the newborn The direct antiglobulin test (also known as "DAT") is performed to detect in vivo sensitization of RBCs with IgG or complement. In vivo coating of RBCs with IgG antibody or complement are associated with the following clinical conditions: autoimmune and drug-induced hemolytic anemia (AIHA), hemolytic disease of the fetus and newborn (HDFN), and hemolytic transfusion reaction (HTR). The indirect technique is performed to detect in vitro sensitization of RBCs for antibody screening and compatibility testing purposes. Both hemagglutination and hemolysis techniques are in vitro testing methods used for the detection of antigens or antibodies.

The most frequently encountered immunoglobulin demonstrated in patients with Multiple Myeloma is:

Ig G The most commonly encountered form of immunoglobin in patient suffering from Multiple Myeloma is Ig G at 52%. Four subtypes of IgG heavy chains are known to exist among patients with IgG myeloma (IgG1, IgG2, IgG3, IgG4). The subclasses of cases of IgG myeloma are distributed as follows: 65% gamma G1, 23%IgG2, 8% IgG3, 4% IgG IgM occurs in 12% of patients with Multiple Myeloma. Ig A occurs in 22% of patients with Multiple Myeloma. IgE is rarely detected in patients with Multiple Myeloma.

Which of the following antibody types is the predominant serum antibody seen in the secondary immune response:

IgG In primary responses, the first and predominant major class of antibody produced is IgM. In the secondary response, IgG is produced quickly and becomes the predominant antibody. IgA is not seen as a predominant antibody in the serum, however, it is found as the predominant antibody in the mucosa. In primary responses, the first and predominant major class of antibody produced is IgM. In the secondary response, IgG is produced quickly and becomes the predominant antibody. IgD is found primarily in B lymphocytes and does not play a major role in serum immune responses.

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

Which class of antibody can agglutinate erythrocytes (RBCs) after anti-human globulin (AHG) is added to the test tube?

IgG Some antibodies, such as IgG, do not directly agglutinate erythrocytes (RBCs). This incomplete or blocking type of antibody may be detected by an enhancement medium, such as anti-human globulin (AHG) reagent. If AHG is added, a second antibody binds to the antibody present on the erythrocytes. AHG is created to bind with IgG antibodies at the Fc portion of these antibodies. AHG will bind to both bound and unbound IgG antibodies. When IgG is bound to red blood cells, AHG produces visible agglutination in a test tube. IgA is the predominant immunoglobulin in secretions, such as tears and saliva. IgA forms a complex molecule termed secretory IgG, which is critical in protecting body surfaces against invading microorganisms because of its presence in seromucous secretions. IgE is unique in that it binds strongly to a receptor on mast cells and basophils. Together with antigen, IgE mediates the release of histamines and heparin from mast cells and basophils. IgM is a pentamer with multiple binding sites that enable higher avidity. IgM antibodies, such as anti-A and anti-B, readily agglutinate erythrocytes with the corresponding antigen, A or B, optimally at a colder temperature than IgG without any enhancement agent, such as anti-human globulin (AHG).

Lymphocyte pleocytosis refers to a(n) _____________ in a CSF when compared to a normal sample.

Increased number of lymphocytes The presence of a greater than normal number of lymphocytes in the spinal fluid is termed lymphocyte pleocytosis. Typically, majority of cells seen in a normal adult CSF specimen are lymphocytes and monocytes (70:30 ratio). This ratio is reversed in children.

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 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.

How does Aspirin (salicylic acid) affect platelet function?

Inhibiting cyclooxygenase Aspirin, or acetylsalicylic acid, acts as an antithrombotic agent due to inhibition of platelet function by acetylation of the platelet cyclooxygenase, also known as COX. This prevents arachidonic acid from catalyzing the reaction that allows for normal coagulation, which results in an irreversible inhibition of platelet-dependent thromboxane formation. Aspirin has no effect on inhibiting lipids for platelet function. Aspirin has no effect on inhibiting carbohydrates for platelet function. Aspirin does not activate nucleic acids for platelet function because platelets lack a nucleus.

A drug that is administered through which of the following routes will reach peak level the quickest?

Intravenous (IV) A drug that is administered IV will offer the most direct route of delivery for the drug, reaching peak level the quickest (15 - 30 minutes after injection/infusion). A drug that is injected IM will reach peak level at 30 minutes to one hour after injection; a drug that is taken orally will reach peak level approximately one hour after the drug is taken (if the half-life is > two hours). Other modes of drug administration include subcutaneous injection, inhalation, transcutaneous, and rectal delivery through a suppository.

Which of the following statements is FALSE regarding troponin as a marker of myocardial infarction (MI)?

It rises much sooner after a myocardial infarction than CK-MB Troponin and CK-MB both tend to rise approximately 3 hours after a MI (hence why the first answer choice is false); however, troponins can stay elevated up to 2 weeks as CK-MB tends to return to baseline around 36 hours. Troponin is potentially more specific for myocardial damage than CK-MB and stays elevated longer. It may eventually replace CK-MB as the standard marker of myocardial damage. In addition, troponin T has been known to be elevated in the setting of even mild degrees of renal failure.

A delayed hemolytic transfusion reaction is most likely to be the result of which of the following antibodies?

Jka Jka antibodies are known to disappear from circulation quickly (often within a few weeks), which can cause a false negative antibody screen and subsequent transfusion of antigen positive units that will stimulate the patient to produce antibodies and can cause a delayed hemolytic transfusion reaction. A antibodies (all ABO antibodies) would cause an immediate hemolytic transfusion reaction. Lea antibodies are rarely implicated in acute hemolytic transfusion reactions, but are NOT known to cause delayed hemolytic transfusion reactions. B antibodies (all ABO antibodies) would cause an immediate hemolytic transfusion reaction.

Laser light can be described by all of the following characteristics EXCEPT:

LASER is an acronym for light amplified by stimulated energy radiation LASER is an acronym for light amplification by stimulated emission of radiation. Intensity is a characteristic of laser light. In contrast to other forms of diffuse radiation, laser light is concentrated. Lasers sort the energy in atoms and molecules, concentrate it, and release it in powerful waves. Photons, the basic unit of all radiation, travel the length of a laser where they are reflected back and forth. Finally, they gain so much energy that they exit as a powerful beam. Laser light is used in flow cytometry for cell sorting and identification of cells. The process of flow cytometry involves placing a suspension of fluorochrome dye-stained cells into a flow chamber under pressure. These stained cells pass through a laser beam that activates the dye. Cellular fluorescence is collected and transmitted to a computer program that can manage cell sorting before further analysis and identification of cells. Monochromaticity is a characteristic of laser light. Laser light is almost exclusively of one wavelength or color. Through the use of fluorescent dyes, laser light can occur in numerous wavelengths. Flow cytometry performs fluorescence analysis on single, fluorochrome stained cells in a suspension that pass through a laser beam in a single file. The laser activates the dye, and the cell fluoresces. Fluorescence is collected by optical sensors and the information is transmitted to a computer which controls all decisions regarding data collection, analysis, and cell sorting.

Which of the following would most likely occur as the result of hemodilution?

Low serum electrolyte values A dilutional effect caused by the sample being hemodiluted, would not cause high serum electrolyte values since they have been diluted out. The anion gap could remain the same or become decreased. Finally, the electrolyte concentrations could not remain the same, since there will be a smaller amount in the sample to test due to the diluent.

A technologist decides to make a 1:20 dilution of cerebrospinal fluid (CSF) after briefly evaluating a portion of the sample microscopically. After making the dilution and charging the chambers, the number of cells that are observed in each of the large squares of the hemocytometer is >100. What should the technologist do to obtain the most accurate count?

Make a larger dilution.

Although not always the most practical, animal inoculation may be used to identify all but which of the following conditions?

Malaria Malaria cannot be identified by animal inoculation. The parasite must be identified in peripheral blood smears of patients that are infected. The parasite infects the red blood cells and multiple forms are seen in the cells, most commonly, the ring form. Leishmania, Trypanosoma, and Toxoplasma can be tested via animal inoculation, however, this is not typically used anymore. Each parasite will have host specificity for a certain animal. Typical animals used are mice, guinea pigs, and hamsters. The specimen can vary depending on the parasite suspected.

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:

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.

Identify the cell in this illustration indicated by the arrow:

Metamyelocyte The WBC in this image is a metamyelocyte. As maturation continues in the granulocytic series the nucleus of the metamyelocyte becomes kidney or bean shaped. Monocytes contain a lacy chromatin pattern that becomes finer as the cell matures. The nuclear shape is commonly folded or horseshoe shaped. Myeloblasts can be identified by containing 1 to 5 nucleoli along with less condensed nucleus and dark cytoplasmic color. The nucleus to cytoplasmic ratio is high, indicating that the nucleus occupies most the space of the cell. As cells mature, nucleoli should not be seen. Promonocytes are the second stage of monocyte maturation and therefore will be very similar to myeloblasts with fewer nucleoli and a more mature chromatin.

A patient is admitted to the emergency room with lethargy and pallor. The CBC results are as follows: RBC = 4.1 x 1012/L Hemoglobin = 7.9 g/dL Hematocrit = 29% How would you classify this anemia?

Microcytic, hypochromic First, the RBC indices must be calculated. The MCV ((Hct/RBC) x 10) = 71 fL. Since the reference range for the MCV is 80-100 fL, this anemia would be classified as microcytic. The MCHC ((Hgb/Hct) X 100) = 27%. Since the normal range for the MCHC is 33%-36%, this would indicate hypochromia which correlates with the MCH findings. The correct answer is therefore microcytic, hypochromic anemia.

A 67-year-old homeless man was seen in the ambulatory clinic for chest pain and sputum production. A mycobacterial culture showed the following: rough, non-pigmented colonies, which grew after two weeks at 35oC and failed to grow at other temperatures, serpentine cording, a strongly positive niacin test, nitrate reduction, and loss of catalase activity after heating at 68oC in pH 7. What is the most likely identification?

Mycobacterium tuberculosis The correct choice is Mycobacterium tuberculosis. It is the only Mycobacterium species listed that is niacin positive.

The property MOST responsible for the migration of proteins in an electrical field is:

Net surface charge Though molecular weight, endosmotic flow, and voltage can play a role in various characteristics of protein electrophoresis, the net surface charge is the PRIMARY property responsible for the migration of the proteins.

Which of the following choices represents the characteristic indicator, fermentable sugar(s), and bacteriostatic agent(s) that are present in MacConkey agar respectively?

Neutral red / lactose / bile salts and crystal violet MacConkey agar contains neutral red, which is a dye that is absorbed by the colonies during fermentation. Lactose is the only sugar present in the medium and lactose fermenters appear pink to red and non-fermenters appear clear or colorless. The inhibitory agents are bile salts and crystal violet, Xylose-Lysine-Desoxycholate (XLD) agar uses phenol red as the pH indicator for fermentation. Lactose, sucrose, and xylose are present in the medium and fermenters appear yellow whereas non-fermenters appear clear or colorless. The medium also contains desoxycholate, which inhibits Gram positive organisms. There are also bile salts present, but in lower concentrations than other enteric media (such as Salmonella-Shigella or Hektoen Enteric) for better recovery of Shigella species. Eosin-Methylene Blue (EMB) agar uses Eosin Y and methylene blue to both allow the color change to occur with fermentation of the sugar occurs, dropping the pH, and also as the bacteriostatic agent by inhibiting the growth of Gram positive bacteria. Lactose and sucrose are both incorporated into the medium and lactose and sucrose fermenters appear blue/black and non-fermenters appear clear and colorless. Hektoen Enteric (HE) agar uses bromothymol blue in the agar as the pH indicator for color change during fermentation. Lactose, salicin, and sucrose are all present in the medium and fermenting colonies appear orange to salmon pink. Non-fermenting colonies appear green to blue-green. The inhibitory agent is bile salts at a concentration that inhibits Gram positive organisms as well as many Gram negative organisms that are normal fecal flora.

You are running quality control for Hemoglobin A1C by high-pressure liquid chromatography (HPLC). The high control was 2.5 standard deviations above the mean. The low control was 2.2 standard deviations below the mean. Should you continue to run patient samples?

No. These QC values indicate a violation of the Westgard R4S rule and are therefore cause for rejection. This run of QC does indicate a violation of a Westgard rule for QC. The R4S rule is violated when the difference, or range, between the two control values within the run is greater than 4 SD. This is a Westgard rule that must be resolved before patient results can be reported. The 13S rule is violated when the result of one of the two quality control results is outside of 3 SD. The 41S rule can be violated in two ways. The first is when with one level of control, four consecutive results fall on the same side of the mean and exceed +1 SD or the mean or -1 SD of the mean. The rule can be used with two levels of control. The rule is violated when both levels of control for two runs in a row exceed +1 SD from the mean or -1 SD from the mean.

This suspicious form was recovered from a nodule biopsy. It measures 300 µm in length and lacks a sheath. Identify the suspicious form.

Onchocerca volvulus microfilaria Onchocerca volvulus is the only microfilarial choice that is typically recovered from nodule biopsies and lacks a sheath. Trypanosoma trypomastigotes measure 15-20 µm, and may be found in the blood, lymphatic fluid, or CSF of infected individuals. A pseudoparasite is an object that may be mistaken for a parasite, and is an incorrect choice. Wuchereria bancrofti microfilaria are sheathed and slightly smaller in size, compared to Onchocera microfilaria. W. bancrofti microfilaria live in the lymphatic tissues, especially in the lower extremities.

A pregnant female has been injected with Rh Immune Globulin (RhIG) antenatally (28 weeks gestation) and has a positive antibody screen at delivery. The antibody has been confirmed as anti-D alone and reacts only weakly (1+ in the indirect antiglobulin test). This antibody may be the result of:

Passive anti-D (RhIg) received at 28 weeks. Rh Immune Globulin is administered at 28 weeks of gestation and at delivery to help prevent pregnant women from becoming actively immunized to the D antigen. RhIG is given because during pregnancy and at delivery fetal blood can enter maternal circulation. This exposure to the D antigen puts the mother at risk for becoming sensitized and making an anti-D. Women who are Rh negative carrying an Rh positive fetus now receive RhIG at 28 weeks (antenatal) and at delivery (within 72 hours of delivery) to clear fetal red blood cells from maternal circulation. The RhIG can attach to fetal red blood cells which are then cleared by macrophages. At delivery some Rh negative women have a weakly reactive anti-D still in circulation from RhIG administration at 28 weeks of gestation (antenatal). The anti-D has been demonstrated to stay in circulation 2 months or even longer in some cases. Massive fetomaternal hemorrhage may sensitize a woman but this would not be detected at delivery. Wharton's jelly would be present in the cord sample from the baby and may cause incorrect results (rouleaux) for the baby. The mother is Rh negative since she received RhIG so the anti-D present is not an autoantibody.

A maternal sample is collected 2 hours after delivery and a type and screen is performed. The screen is weakly positive and an anti-D is identified. Which of the following is the most likely cause of the positive antibody screen?

Passive anti-D from RhIG given at 28 weeks. Rh Immune Globulin is administered at 28 weeks of gestation and at delivery as a way to help prevent pregnant women from becoming actively immunized to the D antigen. RhIG is given because during pregnancy and at delivery fetal blood can enter maternal circulation. This exposure to the D antigen can put the mother at risk for becoming sensitized and making an anti-D. Women who are Rh negative carrying an Rh positive fetus now receive RhIG at 28 weeks (antenatal) and at delivery (within 72 hours of delivery) to clear fetal red blood cells from maternal circulation. The RhIG can attach to fetal red blood cells which are then cleared by macrophages. At delivery some Rh negative women have a weakly reactive anti-D still in circulation from RhIG administration at 28 weeks of gestation (antenatal). The anti-D has been demonstrated to stay in circulation 2 months or even longer in some cases. Anti-D can be made after delivery due to massive fetomaternal hemorrhage. However, this would not be present in the sample 2 hours after the exposure. If the mother is a candidate for RhIG the fetal red cells are expressing the D antigen. Therefore, the neonate would not make an anti-D. Additionally, a neonate does not have a mature immune system so antibody production has not begun at delivery. Given the mother's history of receiving RhIG at 28 weeks, a false positive is unlikely.

Which of the following actions could lead to musculoskeletal disorders?

Performing assays that require repetitive pipetting Repetitive actions such as pipetting or typing are potential sources of motion injuries (such as carpal tunnel syndrome). The term musculoskeletal disorders (MSDs) is used to describe the most common physical ergonomic stressors where muscles, nerves, tendons, joints, or discs are affected. MSDs include carpal tunnel syndrome, rotator cuff syndrome, tendinitis, and sciatica. Any type of stressor likely to lead to an MSD is called a "work-related musculoskeletal disorder hazard." The other three answer choices are examples of preventitive measures against MSDs.

Fetal lung maturity can be determined from amniotic fluid because the surfactant is PRIMARILY composed of:

Phosphatidylcholine and other phospholipids Assessment of the status of amniotic fluid phospholipids has become important in determining fetal lung maturity. Pulmonary surfactant is a mixture of lipids, proteins, and glycoproteins and it is responsible for maintaining the surface tension of the alveoli preventing them from collapsing. As the fetal lungs mature, the phospholipid levels in the amniotic fluid increase, especially phosphatidylglycerol (PG) and phosphatidylcholine (lecithin). Another phospholipid, sphingomyelin has a constant amniotic concentration during pregnancy. It has been documented that the ratio of lecithin to sphingomyelin (L/S ratio), with respect to pediatric gestational age, is a reliable predictor of fetal lung maturity.

Which of the following analytes will be falsely increased due to hemolysis?

Potassium, Magnesium, Iron, Total Protein Extreme care should be taken in order to avoid hemolysis of the specimen. When the specimen is hemolyzed, the concentration of analytes is changed and results are inaccurate. Some falsely increased results include potassium, magnesium, iron, lactate dehydrogenase, phosphorus, ammonia, and total protein. Some of the results falsely decreased include red blood cell count, hemoglobin, and hematocrit.

Examine the KIA tube on the right in the image provided and determine which of the following organisms produces the biochemical reaction seen.

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.

Which of the following is true of the nuclear appendage seen in this image?

Seen only in women

The abnormal cells indicated by the arrows are indicative of which of the following?

Sickle cell disease Sickle cell disease is the correct answer. In sickle cell disease, the peripheral blood smear shows variable anisocytosis and poikilocytosis with sickle cells (drepanocytes) and target cells (codocytes). In vitamin B12 deficiency characteristically shows macrocytic, normochromic RBCs on the peripheral blood smear, in addition to marked anisocytosis and poikilocytosis. Patients with severe burns typically have erythrocyte budding, schistocytes and spherocytes on the peripheral blood smear. Iron deficiency anemia generally presents with microcytic, hypochromic cells on the peripheral blood smear.

Which of the following is a selective medium for Campylobacter jejuni?

Skirrow agar Selective media required for the isolation of Campylobacter jejuni include Skirrow agar, Campy-BAP, Preston Campylobacter medium, and Butzler's selective medium. CNA is a selective growth medium for the isolation of gram positive cocci. Thayer-Martin is a selective medium used to isolate Neisseria gonorrhoeae with suppression of most other bacteria and yeast. Cystine-tellurite blood agar is used for isolating Corynebacterium diphtheriae (produce black colonies).

Why are small dense LDL molecules more atherogenic?

Small dense LDL molecules have greater mobility in the endothelium and arterial wall. Most researchers believe that the small size and increased density of LDL molecules found in atherogenic dyslipidemia enable the molecules to more easily invade the endothelium and arterial wall of vessels, making them ore proatherogenic. LDL particles are considered to be a good marker for coronary heart disease (CHD) risk.

All of the following analytes would be significantly increased in a plasma sample as a result of hemolysis, EXCEPT?

Sodium Sodium is the most abundant cation in the extracellular fluid (ECF) and largely determines the osmolality of the plasma. Sodium concentration in the ECF is much larger than inside the cells. Higher levels of sodium in the blood could occur with excess water loss or decreased water intake.Potassium, LDH (lactate dehydrogenase), and AST (aspartate aminotransferase) are found in much higher concentration in intact RBCs than in serum, so when cells are lysed due to hemolysis, those compounds spill into the plasma and falsely increase the result. Potassium is the major intracellular cation in the body, with a concentration 20 times greater inside the cells than outside. The highest levels of total LDH are seen in pernicious anemia and hemolytic disorders. AST intracellular concentration is approximately 7000 times higher than the extracellular concentration.

A variety of additives are used in blood collection tubes. Which of the following additives inhibits glycolysis?

Sodium fluoride Sodium fluoride is found in gray top tubes and its purpose is to inhibit glycolysis (metabolism of glucose by red blood cells) for the determination of accurate glucose levels. EDTA prevents blood from clotting by binding calcium which in turn inhibits the coagulation cascade. EDTA is found in the lavender, pink, white, royal blue, and tan top tubes. The gel in the tube is used to form a barrier between plasma/serum and blood cells upon centrifugation. Lithium/sodium heparin is an additive used to prevent clotting by inhibiting thrombin and thromboplastin. It is found in green and light green tubes.

An electrolyte panel is composed of which of the following tests?

Sodium, potassium, chloride, CO2 Electrolytes are essential for the normal function of nerve, muscles, and heart activities. An electrolyte panel is composed of sodium, potassium, chloride, and CO2. Glucose is a carbohydrate, albumin is a protein, and cholesterol is a lipid.

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 gram positive cocci. The catalase reaction was positive and the coagulase test was negative. This isolate is a common agent of urinary tract infections. What is the name of this isolate?

Staphylococcus saprophyticus Staphylococcus saprophyticus is the correct response. Staphylococcus saprophyticus colonies are smooth but not pigmented and the gram-positive cocci in slide preparations. The catalase test is positive and 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 with gram-positive cocci on the slide preparation and having both tests positive for catalase and coagulase. 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 and catalase is positive. 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. It is considered normal flora and is associated with nosocomial infections. Micrococcus spp. are usually considered contaminants of clinical specimens and are rarely implicated as cause of infections in humans.

The reaction which differentiates crystals from starch is:

Starch stains blue black with iodine Starch granules can be differentiated from crystals by the addition of iodine. Starch granules will take on a blue/black appearance where crystals do not.

T lymphocytes are characterized by all of the following functions EXCEPT which?

Synthesize antibody T lymphocytes perform all of the listed functions EXCEPT synthesizing antibodies. B lymphocytes and plasma cell synthesize antibodies (immunoglobulins). T lymphocytes secrete cytokines, comprise the majority of cells in the lymphocyte pool, and help regulate immune response.

What is the primary target of HIV (human immunodeficiency virus)?

T-helper cells T-helper cells is the correct response. The targets of the HIV virus are the CD4+ T cells (T-helper cells), macrophages, and monocytes. As the virus replicates patients will eventually suffer from a decrease of the T-helper cells, which are critical to the host's immune response. Patients suffering from HIV infections suffer a decreasing functional CD4+ T cell population as the disease progresses, which leads to the acquired immune deficiency syndrome (AIDS). The heart, liver, and lungs do not possess the CD4 receptor to which the HIV virus must attach in order to enter a cell for replication.

When a Specked Nuclear Antibody (ANA) pattern is observed, what follow-up test for antibodies related to Systemic Lupus Erythematosus (SLE) is not beneficial?

Testing for antibodies to U1RNP+ and dcSSc U1RNP+ and Scl-70 antibodies are extractable nuclear antigens that yield a speckled ANA pattern but they are not associated with Systemic Lupus Erythematosus (SLE). U1RNP+ is associated with mixed connective tissue disease/undifferentiated connective tissue disease; Scl-70+ is associated Diffuse cutaneous scleroderma. If other criteria suggest that the patient is suffering from Systemic Lupus Erythematosus (SLE), the presence of Smith (Sm) and SS-A/SS-B+ are the most important antibodies to identify. Speckled ANA patterns can be followed-up with testing for antibodies to the extractable nuclear antigens (ENA) which include: Sm (Smith), U1-RNP, SSA/ SSB and Scl-70. If other criteria suggest that the patient is suffering from Systemic Lupus Erythematosus (SLE), the presence of Smith (Sm) and SS-A/SS-B+ are the most important antibodies to identify.

All of the following regarding Anti-A and Anti-B reagents used in forward typing for ABO typing are true EXCEPT?

The antibodies are IgG. The correct answer is "The antibodies are IgG". This is the only statement about Anti-A and Anti-B reagents for forward typing that is NOT true. The antibodies in these reagents are IgM.All of the other choices are true of the reagents. The antibodies in the reagents are monoclonal, they are highly specific, and the reagents are designed to produce an expected 3+ or 4+ reaction with the corresponding antigens (Anti-A with A antigen and Anti-B with B antigen).

What is the explanation for a discrepancy in the following front type and back type in a newborn? Anti-A = neg Anti-B = neg A1 cells = neg B cells = neg

The baby's antibodies are undeveloped. At birth, ABO antibodies are generally absent or of maternal origin. ABO antibody production begins at about 4 - 6 months of age.

Which of the following statements is true regarding the Gram-stained smear that is represented by this image?

The smear is underdecolorized and shows precipitated and crystallized stain. This smear is underdecolorized, showing precipitated and crystallized stain. This field would not be appropriate for examination because the cells are clumped in distorted masses, along with precipitated and crystalline pieces of stain that are easily visible. Artifacts are often not spread in a uniform manner across the slide. Other clues that indicate precipitate and other artifacts on Gram-stained smears includes refractivity and nonuniformity in size.

What is the main function of leukocytes?

To fight off infection. Leukocytes' (white blood cells) main function is to fight off infection. Thrombocytes' (platelets) main function is to assist in the coagulation process. Erythrocytes' (red blood cells) main function is to transport oxygen from the lungs to the tissues and carbon dioxide from the tissue to the lungs to be expelled. Plasma's functions include the transportation of nutrients, hormones, nitrogenous waste, electrolytes, and other substances throughout the body.

What element is indicated by the arrow on this slide?

Waxy cast The element in this image is a waxy 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 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. A cylindroid resembles a cast, with the exception that one end tapers out. They are considered to have the same significance as casts. The arrow is not pointing at white blood cells.

The cells that are indicated by the arrows in this urine sediment (using phase contrast microscopy) are:

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.