LabCe Questions III

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? Please select the single best answer 2.5 x 10^9/L 25 x 10^9/L 2,500/L 25,000/L

2.5 x 10^9/L First, determine the number of WBCs 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 10^3 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 10^3 WBC/µL) x (106 µL/L) = 2.5 x 10^9 WBC/L

How many standard deviations (SD) above and below the mean is accepted as being an appropriate control limit range on a control chart utilizing the Westgard rules: Please select the single best answer 1 SD 2 SD 3 SD 4 SD

3 SD Three standard deviations (3 SD) are used to limit the potential for erroneous results and to identify any random or systemic errors that may occur in testing. However, additional Westgard rules are also used to identify errors that occur within the 3 SD range. These may be warning rules or mandatory rules and are intended to flag a potential issue before patient care is affected. For example, the 22s rule identifies if two consecutive points are more than 2 SD on the same side of the centerline. A laboratory that only accepts results 1 SD from the mean will lead to a false rejection of many quality control results as only 66.8% of samples tested are expected to fall within this range. Some Westgard rules flag quality control results that are 2 SD from the mean. However, a laboratory that only accepts results that are within 2 SD from the mean will have an increased rate of false rejections. Samples that are greater than 3 SD from the mean should never be accepted.

What transferrin saturation level would be indicative to investigate further for hereditary hemochromatosis (HH)? Please select the single best answer 40% 45% 35% 25%

45% A persistent transferrin saturation level of 45% or greater is often recommended as the value that indicates further investigation. This is a progressive iron overload and in addition, other iron studies should be evaluated, any value under 45% would be considered normal range.

Given the following information, calculate the results in mg/24 hrs. for a 24-hour urine protein. Total volume for 24 hours = 2,400 mL Urine protein = 2.7 mg/dL Please select the single best answer 64.8 mg/24 hrs. 10.87 mg/24 hrs. 57.5 mg/24 hrs 5.89 mg/24 hrs

64.8 mg/24 hrs. 2.7 mg/dL X 2400 mL/24 hr X 1 dL/100 mL = 2.7 mg X 2400 100 = 64.8 mg/24 hr

Hymenolepis nana

dwarf tapeworm, most common US tapeworm, direct infection The egg of Hymenolepis nana, which is hexacanth or lancet-shaped with six hooklets. It is round to oval with a thin, smooth membrane and an outer shell. There is a clear space between the membrane and shell and 4-8 filaments emerge from its inner membrane.

What is the normality of 32.1% HCl? (HCl has a positive valence of 1) Please select the single best answer 3.2N 8.8N 11.2N 15.7N

8.8N To calculate the normality of 32.1% HCl, you would use the following equation: N = % x 10/eq wt. You would start solving this problem by calculating the eq wt of HCl by using the following equation: eq wt = mol wt/pos valence. eq wt = mol wt/pos valence eq wt = 36.5/1 eq wt = 36.5 N = % x 10/eq wt N = 32.1 x 10 / 36.5 N = 321 / 36.5 N = 8.8N

Which of the following statements is true about the emergence of penicillin-resistant strains of Streptococcus pneumoniae? Please select the single best answer Resistance to penicillin disk diffusion is reliable. A zone size = 20 mm surrounding a 1µg oxacillin disk must be confirmed. Penicillin resistance is reliable and reportable with a zone size of = 20 mm with the oxacillin disk screen. A zone size of = 20 mm with the oxacillin disk screen must be confirmed with an MIC method to determine if Penicillin is susceptible or resistant.

A zone size of = 20 mm with the oxacillin disk screen must be confirmed with an MIC method to determine if Penicillin is susceptible or resistant. With the emergence of resistant strains of Streptococcus pneumoniae, it has been determined that the penicillin disk diffusion test is not reliable for determining penicillin susceptibility. The oxacillin screening test may be used but it is only reliable in predicting organism susceptibility if the zone measures = 20 mm; oxacillin screen tests with zones of inhibition < 20 mm must be confirmed by MIC methods. Resistance to penicillin disk diffusion is not reliable as the method does not have sufficient sensitivity. With the oxacillin screen test, a zone size = 20 mm surrounding the 1µg oxacillin disk does not need to be confirmed. Penicillin resistance is not reliable and reportable with a zone size of = 20 mm with the oxacillin disk screen. It must be confirmed with an MIC method.

The ketone component that is measured by the nitroprusside reaction is: Please select the single best answer Acetoacetic acid Beta-hydroxybutyric acid Acetone C-Reactive Protein

Acetoacetic acid The ketone component that is measured by the nitroprusside reaction is acetoacetic acid. A positive ketone result is demonstrated as a color change from purple to violet. The intensity of the violet color is proportional to the concentration of ketone bodies in the urine.

Which of the following blood tests is used in the determination of prostate cancer? Please select the single best answer Acid phosphatase Alkaline phosphatase (ALP) Alanine aminotransferase (ALT or SGPT) Creatinine

Acid phosphatase Acid phosphatase test helps in diagnosing prostate cancer. It should be collected in a gel-separator tube. Serum/plasma should be frozen immediately and transported frozen. ALP is the test used to evaluate liver function. It requires to be a fasting collection and collected in a gel-barrier tube. Serum should be separated from cells immediately and refrigerated for storage. Alanine aminotransferase (ALT or SGPT) test helps to determine hepatic disease. It should be collected in a serum (red top) or plasma tube (green top). Serum/plasma should be separated from cells immediately and refrigerated for storage. Creatinine is a test used to evaluate kidney function. It should be collected in a gel-barrier serum tube (red or gold top). Serum should be separated from cells immediately and refrigerated for storage.

At a minimum, how frequently should an ocular micrometer be calibrated? Please select the single best answer Only once per year Once every six months Once every month After major cleaning of the microscope or replacing objectives and as part of annual maintenance.

After major cleaning of the microscope or replacing objectives and as part of annual maintenance. The ocular micrometer must be calibrated whenever the microscope is thoroughly cleaned, as part of annual maintenance, and when the objectives are replaced. The micrometer must be calibrated at three powers; 10x dry, 40x dry, and 100x oil immersion. Results of the micrometer calibration should be posted near the microscope for technologist reference. It is an understandable assumption to state that the micrometer must be calibrated once a year. However, circumstances may require additional calibration if objectives are changed or the microscope undergoes detailed cleaning between annual calibration. Calibrating the micrometer every six months is too frequent and unnecessary. Calibrating the micrometer every month is too frequent and unnecessary.

The colonies illustrated in the upper photograph were recovered from the aspiration of nasal secretion from a patient with acute sinusitis. The 48-hour colonies on blood agar are relatively small, entire, white, and non-hemolytic. Colonies growing on chocolate agar are also small, smooth, and entire with light yellow pigmentation. On Gram stain, pale-staining, Gram-negative coccobacilli are observed, with a tendency to form long, narrow filaments. The lower photograph reveals tube reactions with a KIA: Acid/Acid and the oxidative utilization of several carbohydrates except for xylose and mannose. Nitrate reduction is positive, and ornithine and arginine decarboxylases are negative. From the observations, select from the multiple choices the genus/species name of this isolate. Please select the single best answer Moraxella catarrhalis Kingella kingae Aggregatibacter aphrophilus Eikenella corrodens

Aggregatibacter aphrophilus Aggregatibacter aphrophilus is the correct response. Colonies growing on blood agar are small, entire, smooth, gray-white, and non-hemolytic. Colonies growing on chocolate agar are also small, smooth, and entire with light yellow pigmentation. On Gram stain, pale-staining, Gram-negative cocco-bacilli are observed, with a tendency to sometimes form long, narrow filaments. A. aphrophilus is saccharolytic and acid is produced from many commonly tested carbohydrates, except xylose. Nitrates are reduced. Moraxella catarrhalis colonies are smooth and gray to white on blood and chocolate agars. The colony remains intact when pushed across the agar plate so is described as being like a "hockey puck." Short, more plump than filamentous, Gram-negative bacilli and coccobacilli are observed on Gram stain. This organism does not utilize carbohydrates (asaccharolytic) but reduces nitrates. Kingella kingae forms large white to beige beta-hemolytic colonies on blood agar and may produce a yellow-brown pigment. Short, plump, Gram-negative rods with square ends and in chains are observed on Gram stains, without the formation of filaments. K. kingae is asaccharolytic with the exception of the oxidative utilization of dextrose and maltose. Eikenella corrodens colonies grow more slowly and are nonhemolytic on blood agar and 45% of the colonies may distinctively pit or corrode the surface of the agar. A chlorine bleach-like odor may be obvious. This organism does not utilize carbohydrates (asaccharolytic).

Which of the following analytes would be increased due to delay in centrifugation? The correct answer is highlighted below Creatinine Ionized Calcium Folate Bicarbonate

Creatinine 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.

Which of the following enzymes is associated with conditions affecting skeletal muscles? Aldolase Alkaline phosphatase (ALP) Gamma-glutamyltransferase 5'-nucleotidase

Aldolase Aldolase is an enzyme that aids in the glycolytic breakdown of glucose to lactate for energy. Aldolase is associated with muscles and is currently used in the monitoring of patients with muscular dystrophy and a few other rare conditions affecting skeletal muscles. A serum ALP measurement's most useful clinical attribute is its sensitivity in distinguishing hepatobiliary disease associates with biliary tree obstruction. It is also used to detect bone disease associated with an elevated osteoblastic activity. Gamma-glutamyltransferase, or GGT, is elevated in liver diseases affecting the biliary system, especially in patients who are heavy drinkers. Serum concentrations of 5'-nucleotidase, or 5NT, reflect hepatobiliary disease with high specificity as well.

What is the first stage in the life cycle of a hemoflagellate? Please select the single best answer Amastigote Trypomastigote Promastigote Epimastigote

Amastigote The hemoflagellate (Trypanosoma spp. and Leishmania spp.) morphologic forms vary in size and shape, presence or absence of an undulating membrane, and presence or absence of a flagellum. The simplest form, the amastigote, is roundish and lacks both of the aforementioned structures. The trypomastigote is considered the most developed stage in the life cycle. It has a full body length undulating membrane and a flagellum that, when present. extends out of its anterior end. The promastigote stage comes after the amastigote state in the life cycle. In this stage, the hemoflagellate begins to elongate and has a cigar shape. The epimastigote stage comes after the promastigote stage and before the trypomastigote stage. It is during this stage that the undulating membrane of the flagella begins to form.

All of the following are applications of real-time PCR, EXCEPT? Please select the single best answer Microbe identification Genotyping HLA components Identification of DNA sequences Amplification of DNA for northern blot

Amplification of DNA for northern blot The amplification of DNA for northern blot is not an application of real-time PCR. Northern blotting is a hybridization method that can be used to detect specific RNA sequences. Real-time PCR can be used to identify microbes that are difficult to grow in laboratory conditions, genotyping for HLA components for donor and recipients in transplantation, identifying specific DNA sequences for particular HLA genotype, amplification of stretches of RNA and more.

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 globulin (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-Lua, -Lea, -Fya, -C Anti-Lea, -Fya, -C Anti-Fya, -C, -Lub

Anti-Fya, -C, -Lub The correct answer is anti-Fya, anti-C, and anti-Lub. 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-Lua, -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.

If detected in antibody screen testing, which of the following antibodies is NOT considered clinically significant in prenatal patients? Please select the single best answer Anti-M Anti-N Anti-Leb Anti-Fya

Anti-Leb Anti-Leb may be detected in antibody screen testing of prenatal patients; however, this antibody is considered clinically insignificant. It is not indicated in causing hemolytic disease of the fetus and newborn (HDFN). Although rarely seen, both anti-M and anti-N can potentially cause mild to moderate HDFN. The most common clinically significant antibodies noted in prenatal patients include the following: anti-Fya, anti-K, anti-D, anti-E, anti-e, anti-C, and anti-c. These IgG antibodies have been determined to cause moderate to severe HDFN.

All of the following Bacillus species would have a wide zone lecithinase reaction, EXCEPT? Please select the single best answer 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.

The primary mechanism responsible for glomerular filtration is: Please select the single best answer Osmotic gradient Concentration of blood components Rate of blood flow through the kidneys Hydrostatic differential in glomerular tufts

Hydrostatic differential in glomerular tufts The hydrostatic pressure in the capillaries of the glomerular tuft drives the filtrate across their semipermeable membrane. The normal glomerular filtrate is similar in composition to the plasma, with the exception that molecules with a molecular weight of greater than about 70,000 daltons are not filtered.

Group A beta-hemolytic streptococci are best characterized by which of the following: Please select the single best answer Positive CAMP test Optochin sensitivity Bile esculin-hydrolysis Bacitracin sensitivity

Bacitracin sensitivity Group A streptococci are best characterized by their susceptibility to bacitracin. Bacitracin disks are used as rapid screening tools to differentiate group A streptococci from other beta-hemolytic streptococci. The CAMP test is used for the identification of group B streptococci. It detects the production of a diffusible, extracellular protein that enhances the hemolysis of sheep red blood cells by Staphylococcus aureus. Optochin sensitivity is used to differentiate Streptococcus pneumoniae (sensitive) from other alpha-hemolytic streptococci (resistant). The hydrolysis of bile esculin is a characteristic used to differentiate enterococci from other streptococci.

Which of the following statements is correct regarding total laboratory automation (TLA)? Please select the single best answer Back-end systems may include the removal of specimens from the analyzer. Front-end systems may include the removal of specimens from the analyzer with transport to storage. Front-end systems may include retrieval from storage. Back-end systems may include the identification of specimens.

Back-end systems may include the removal of specimens from the analyzer. TLA refers to automated devices and robots integrated with existing analyzers to perform all phases of laboratory testing. Back-end systems may include removal of specimens from the analyzer and transport to storage, retrieval from storage for retesting, re-aliquoting, or disposal. Front-end systems can identify and label specimens, centrifuge the specimen and prepare aliquots, and sort and deliver samples to the analyzer.

The organism that is a strict anaerobe, non-motile, gram-negative bacillus, occurring in abscesses and associated with peritonitis is MOST likely: Please select the single best answer Haemophilus spp. Bordetella spp. Bacteroides spp. Brucella spp.

Bacteroides spp. Bacteroides species are the most common isolates of the anaerobic gram-negative bacteria in the clinical laboratory. This family of bacteria is non-motile. Bacteroides spp. are frequently isolated from intra-abdominal infections (such as in abscesses) resulting from a tear in the intestinal mucosa. Haemophilus spp. are not strict anaerobes. Bordetella spp. and Brucella spp. are both aerobes.

Which of the following analytes would be decreased due to delay in centrifugation? Please select the single best answer ALT Creatinine AST Bicarbonate

Bicarbonate 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.

The production of polar germ tubes is a characteristic that is associated with which of these dematiaceous fungi? Please select the single best answer Alternaria species Phialophora verrucosa Bipolaris species Curvularia species

Bipolaris species Bipolaris species is the correct answer because it can produce germ tubes extending from both sides of a conidium when incubated in water at 25° C for up to 24 hours. Hence, the name Bipolaris. Alternaria species is not known to produce germ tubes. Alternaria species is characterized by the production of drum stick-shaped multicelled, muriform macroconidia called dictyospores. Phialophora verrucosa is not known to produce germ tubes. Phialophora verrucosa will produce urn-shaped phialides. Curvularia species is not known to produce germ tubes. Curvularia species is known to produce curved multicelled macroconidia with a swollen central cell.

A gram-positive bacillus that has a rod-coccus cycle (short, thin rods in young cultures and cocci in older cultures) and an odor resembling cheese is: Please select the single best answer Rothia spp. Corynebacterium diphtheriae Brevibacterium spp. Dermabacter hominis

Brevibacterium spp. The characteristics described in the question are those of Brevibacterium species. Brevibacterium has its habitat in milk and milk products, and is responsible for both the color (yellow) and aroma of certain cheeses. It rarely causes infection in humans. It could cause bacteremia in association with indwelling catheters in immunocompromised individuals. Rothia spp. appear as extremely pleomorphic, coccoid and bacillary on gram stain. Rothia is rarely a cause of human disease. In rare cases, Rothia could cause endocarditis. Corynebacterium diphtheriae stain irregularly, with pleomorphic gram positive rods in palisades, and cause diphtheria. Dermabacter hominis are coccoid to short gram-positive rods, and this species has been isolated from blood cultures in the immunocompromised.

Which of the following phenotypes is most indicative of a natural killer (NK) cell? Please select the single best answer CD2+ CD3+ CD5+ CD7+ CD2+ CD3- CD11b+ CD16+ CD11b+ CD16+ CD33+ CD56- CD19+ CD20+ CD22+ CD57-

CD2+ CD3- CD11b+ CD16+ NK cells express CD2, CD11b, and CD16; NK cells do not express CD3, a T cell marker. Other NK cell markers include CD7, CD56, and CD57. CD2, CD3, CD5, and CD7 are all mature T cell markers. CD2 and CD7 are also NK cell markers; however, NK cells are CD3- and CD5-. Although NK cells express CD11b and CD16, CD33 is expressed by monocytes and other myeloid cells. NK cells are CD56+. CD19, CD20, and CD22 are all B cell markers. NK cells are CD57+.

This species of Candida accounts for around 20 percent of urinary yeast isolates. Please select the single best answer Candida albicans Candida glabrata Candida krusei Candida tropicalis

Candida glabrata Candida glabrata is the second most common Candida species to cause disease (Candida albicans is the most common). In urinary yeast isolates, it is identified about 20 percent of the time. Infections tend to be aggressive and difficult to treat with traditional antifungal therapy. It has different sugar assimilation patterns than Candida albicans, notably rapid assimilation of trehalose, so it can easily be differentiated. Candida krusei and Candida tropicalis are seen in immunocompromised patients and cause nosocomial infections.

Which of the following analytes would be increased due to delay in centrifugation? Please select the single best answer Creatinine Ionized Calcium Folate Bicarbonate

Creatinine 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.

What is the characteristic RBC that is uniquely associated with HbSS? Please select the single best answer Target cell (codocyte) Sickle cell (drepanocyte) Polychromatophilic cell Spherocyte

Cycloserine-cefoxitin fructose agar (CCFA) Cycloserine-cefoxitin fructose agar (CCFA) is used to recover Clostridioides (formerly Clostridium) difficle from stool specimens. This media is selective and differential for the recovery and presumptive identification of the organism. C. difficle produces yellow ground-glass colonies and the agar turns from pink to yellow due to the fermentation of fructose. The acid produced changes neutral red, the pH indicator, from red to yellow. While other organisms may grow on the media, they are smaller and do not resemble the characteristic colonies. C. difficle colonies also have the odor of a horse barn and fluoresce chartreuse under UV light. All of the above allow for the presumptive identification of C. difficle on this media. CDC anaerobic blood agar is a general-purpose medium used for the isolation and cultivation of obligate and facultative anaerobic bacteria and is not selective for any given genus or species. Columbia agar with 5% sheep blood is a general-purpose medium used for the isolation of a variety of aerobic bacteria including most fastidious species. Anaerobic bacteria grow poorly on this medium and it should not be selected for their recovery. Phenylethyl agar is a general-purpose medium used for the isolation and cultivation of anaerobic bacteria. It is not selective for making a presumptive identification of C. difficile. The incorporation of phenylethyl alcohol in the formula inhibits most species of facultative anaerobic Gram-negative bacteria.

A 27-year-old missionary presented to the emergency department complaining of severe watery diarrhea, weight loss, abdominal pain, nausea, vomiting, a low-grade fever, and fatigue. (He noted that he had recently returned from a three-week visit to Panama.) Stool specimens were collected and submitted for ova and parasite examination. These images were taken from a wet mount preparation of the concentrate as well as a dry slide stained by modified acid-fast. The cysts seen in both preparations are spherical and measure 8µm in diameter. What is the most likely identification of this parasite? Please select the single best answer Entamoeba histolytica Cyclospora cayetanensis Cryptosporidium parvum Dientamoeba fragilis

Cyclospora cayetanensis Cyclospora cayetanensis, a coccidian protozoa, has been reported worldwide causing disease in humans. Most cases are seen in the tropics and subtropic areas. The incubation period is approximately one week. Symptoms present as severe watery diarrhea, weight loss, nausea and vomiting, low-grade fever, and fatigue. Cysts may be identified in fresh stool by wet mount preparation or trichrome stain. The cysts, however, are small (7µm x 10µm), are not easily detected in a wet mount, and do not hold trichrome stain well. Specimens stained with modified acid-fast or safranin stain produce improved visualization of the organism's morphology. Entamoeba histolytica is an intestinal protozoan that causes a wide variety of illnesses, ranging from asymptomatic presentations to invasive intestinal amebiasis to invasive extraintestinal amebiasis. Invasive intestinal infections include dysentery, colitis, appendicitis, toxic megacolon, and amebomas. Cysts and trophozoites can be seen in fresh stools in both wet mounts (with and without iodine) and trichrome-stained slides. Cysts of E. histolytica are larger than cysts of C. cayentanensis, measuring 12µm x 15µm. Cryptosporidium parvum is also a coccidian protozoan that causes intestinal disease worldwide. Infections may range from asymptomatic presentations to severe, life-threatening illnesses. Symptoms include watery diarrhea, dehydration, weight loss, abdominal pain, nausea and vomiting, and fever. Cysts of C. parvum may be seen in fresh stool by wet mount and trichrome stained preparations. The size of C. parvum cysts is even smaller than C. cayentanensis (4.2µm x 5.4µm). Due to their small size, C. parvum cysts are often missed in ova and parasite exams. Immunofluorescent methods have been developed for identification in stool specimens. Diphillobothrium latum should be easily ruled out as a possible answer. The eggs of D. latum are much larger than C. cayentanensis (55µm-75µm x 40µm-50µm) and do not require trichrome or modified acid-fast staining to be seen.

Identify the urine sediment element shown by the arrow. Please select the single best answer Mucus thread Cylindroid Fiber Amorphous urates

Cylindroid The correct answer is cylindroid. Cylindroid is a type of varied morphology of hyaline casts. Hyaline casts consist of normal parallel sides and rounded ends. On the other hand, cylindroid forms have one tapered end and convoluted shapes that indicate the aging of the cast matrix. Mucus appears as single or clumped threads with a low refractive index. Fiber in a urine specimen from clothing and diapers can be confused with casts by inexperienced techs. To differentiate fiber artifacts from most casts, the specimen can be examined under polarized light. Fibers polarize while most casts other than fatty casts do not. Amorphous urates appear as yellow-brown granules. They could be in clusters that resemble granular casts. Upon refrigeration of urine sample, amorphous urates produce pink sediment.

Which of the following phrases best describes a segmented neutrophil? Please select the single best answer Cytoplasm appears pink-purple due to small specific granules. Cytoplasm contains large red-orange granules. Cytoplasm is a pale blue color with a ground glass appearance. Cytoplasm is clear with no granules.

Cytoplasm appears pink-purple due to small specific granules. A segmented neutrophil has pink cytoplasm that contains fine specific granules scattered throughout the cell. Additionally, a segmented neutrophil typically displays a nucleus with 3-5 lobes connected by a filament. Cytoplasm contains large red-orange granules is incorrect. This would be a descriptor for an eosinophil. Monocytes are commonly characterized as having cytoplasm that is a pale blue color with a ground-glass appearance.Cytoplasm is clear with no granules is incorrect. Many lymphocytes (but not all) have a clear cytoplasm with no granules.

If a pipette is labeled (TC) "to contain" you would do the following: Please select the single best answer 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.

A patient experiences a mild allergic reaction to a transfusion, including urticaria, erythema (skin redness), and itching. What is the most likely source of the allergen? Please select the single best answer IgA on mast cells Drugs or food consumed by the blood donor Insoluble allergens Donor red blood cells

Drugs or food consumed by the blood donor Allergen substances may be drugs or food consumed by the blood donor. The blood recipient forms antibodies to these allergens bound to IgE on mast cells and causes the release of histamines. Mild allergic reactions result from a patient's hypersensitivity to soluble allergens in the plasma of the donor unit. Reactions against donor red blood cells would cause acute or delayed hemolytic transfusion reactions.

All of the following represents an organism paired with its appropriate diagnostic procedure, EXCEPT: Please select the single best answer Trichinella spiralis - serologic testing Cryptosporidium - modified acid-fast stain Echinococcus granulosus - routine ova and parasite examination Schistosoma haematobium - examination of urine sediment

Echinococcus granulosus - routine ova and parasite examination Echinococcus granulosus - routine ova and parasite examination is the correct answer because Echinococcus granulosus tends to form cysts in the lung or liver tissue, diagnosis usually requires an ultrasound, CT, or MRI to detect the location of one or more brood cysts. Diagnosis can also be confirmed by examining cyst tissue or contents for evidence of the parasite. Finally, diagnosis can also be made through a serologic exam or skin testing. Trichinella spiralis - serological testing is the most appropriate method of diagnosis since this organism is typically found in muscle. A muscle biopsy can be performed for identification but is considered a more invasive form of testing when compared to serological testing. Cryptosporidium - to diagnose Cryptosporidium infections, stool specimens must be processed and stained with a modified acid-fast stain to look for the presence of oocysts. In addition, stool immunoassays are available and provide a faster throughput when compared to modified acid-fast testing. Schistosoma haematobium - resides in the human bladder. Therefore, examining urine for the presence of eggs will be the most appropriate form of testing.

What stage is typically seen in stool specimens to identify helminth infections? Please select the single best answer Egg Trophozoite Ooyst Microfilaria

Egg Egg is the correct answer. The diagnostic stage for helminths is the presence of eggs, larvae, or adult worms in a direct wet mount of a stool specimen. For example, Ascaris lumbricoides. Trophozoite is incorrect. Trophozoites are best found in fresh stool specimens that have been permanently stained with a stain such as trichrome. The presence of an amoeba cyst is also helpful in the diagnosis of amoeba, such as Entamoeba histolytica. Oocyst is incorrect. Oocysts are typically best diagnosed in stool specimens using either the zinc sulfate flotation method of removing fecal debris and/or by the modified acid-fast stain procedure. Oocyst can be seen in Cryptosporidium species. Microfilaria is incorrect. Loa loa microfilariae are typically seen on Giemsa-stained blood smears collected between 10:00 am and 2:00 pm, when the recovery rate is the best.

Hemolytic anemias are diagnosed by clinical findings and laboratory test results. All of the following are lab values that are relied on to help diagnose hemolytic anemia EXCEPT. Please select the single best answer Hemoglobin and/or hematocrit Retic count and RBC morphology Bilirubin and haptoglobin Fibrinogen and C-reactive protein

Fibrinogen and C-reactive protein The correct answer is fibrinogen and C-reactive protein. While both analytes are acute phase reactants (proteins) and may be increased during hemolysis, they are NOT specifically related to hemolysis or hemolytic anemia. In hemolytic anemias, the hemoglobin and hematocrit would be decreased and would be useful in the diagnosis of hemolytic anemia. The retic count and RBC morphology would both be helpful in the assessment and diagnosis of hemolytic anemia. The retic count could indicate the bone marrows response, and the RBC morphology may indicate whether the hemolysis is intravascular or extravascular. Both bilirubin and haptoglobin aid in the diagnosis and assessment of hemolytic anemia. Bilirubin levels would be increased and haptoglobin values would be decreased, particularly in intravascular hemolysis.

ACTH controls which step of steroid hormone production? Please select the single best answer First step (cholesterol to cholesterol esters) First step (cholesterol esters to cholesterol) Second step (cholesterol to pregnenolone) Third step (cholesterol esters to pregnenolone)

First step (cholesterol esters to cholesterol) ACTH controls the first step of steroid hormone production, causing cholesterol esters to convert to cholesterol before the subsequent formation of other steroid hormones.

Which of the following is associated with macrocytic anemia? Please select the single best answer Iron deficiency Fish tapeworm Sickle cell disease Beta thalassemia minor

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.

Which of these methods measures fetal hemoglobin or D positive red cells or both to evaluate fetomaternal hemorrhage? Please select the single best answer Rosette test Kleihauer-Betke test Flow cytometry AHG testing

Flow cytometry Flow cytometry measures fetal hemoglobin or D positive red cells or both. In patients with a positive rosette test (a screening for fetomaternal hemorrhage), a quantitative test such as Kleihauer-Betke test or flow cytometry is performed to calculate the dose of Rh immune globulin. The Kleihauer-Betke acid elution is based on the fact that fetal hemoglobin is resistant to acid elution and adult hemoglobin is not resistant to it. Examples of polyclonal antiserum produced for blood bank testing are known as antihuman globulin (AHG) reagents. These products contain multiple antibody specificities.

What is the ultimate goal of secondary hemostasis? Please select the single best answer Formation of a platelet plug Production of coagulation factors Formation of a fibrin clot Dissolution of the fibrin clot

Formation of a fibrin clot The ultimate goal of secondary hemostasis is the formation of a fibrin clot. The formation of a platelet plug is the goal of primary hemostasis.

Platelets are: Please select the single best answer The smallest nucleated cells seen in normal peripheral blood. The largest nucleated cells seen in normal peripheral blood. Fragments of megakaryocyte cytoplasm and do not contain nuclei Fragments of neutrophils

Fragments of megakaryocyte cytoplasm and do not contain nuclei Platelets do not contain nuclei. They are fragments of megakaryocyte cytoplasm. Therefore, they are not the smallest nor the largest nucleated cells found in peripheral blood. Neutrophils do not produce platelets.

Which of the following is true of genotype screening in pharmacogenomics? Please select the single best answer Genotype screening gives a better overall picture of drug metabolism than measuring metabolism with probe drugs. Genotyping does not take into account drug interactions which can affect metabolism. Genotyping typically involves measuring only one mutation site or polymorphism. Genotyping has no known impact on drug metabolism.

Genotyping does not take into account drug interactions which can affect metabolism. Genotyping, while more robust and definitive, cannot factor in environmental or health variables that could affect drug metabolism. Probe drug analysis does factor in these variables, but it is more complex and tedious. Genotyping typically involves measuring many polymorphisms. For example, a laboratory that offers CYP2D6 profiling may measure twelve of the most common and significant mutation sites on this enzyme.

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

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).

A new tech has a presumptive Salmonella species via biochemical identification on a stool culture. To confirm, serological testing is performed. The serological testing is negative and the quality control which was run simultaneously passed. What should the tech do next? Repeat biochemical testing or use an alternate method Repeat serological testing Heat a suspension of the organism and then repeat the serological testing Place a suspension of the organism in the refrigerator and repeat the serological testing

Heat a suspension of the organism and then repeat the serological testing Serotyping of Salmonella species is used to determine species or subspecies of Salmonella. This testing looks for the O (or somatic) antigen that is located in the outer membrane of the cell wall. This antigen is heat-stable, so if the organism is heated, the O antigen will remain. Salmonella serotype Typhi and a few strains of Salmonella serotype Choleraesuis contain a Vi (capsular antigen) located in the polysaccharide capsule of the organism. This Vi antigen can "cover" the O antigen since the capsule is external to the cell wall. The Vi antigen is heat-liable, indicating that heating the sample will remove the Vi antigen, but preserve the O antigen. After heating, repeat serological testing should provide a result for the Salmonella serotype. Repeating the biochemical testing is not required unless there is suspicion that the testing was contaminated, which is not indicated in this question. Repeating the serological testing is not necessary, as the quality control testing indicates that the testing was performed correctly. Refrigerating the specimen will not change the results of the testing. Heating is used to remove the Vi antigen, not cooling.

A 55-year-old white male had the following lab data: RBC 3.7 X 10^12/L Serum iron 220 µg/dL (N: 60-80 µg/dL) TIBC 300 µg/dL (N: 260-400 µg/dL) Hct 32%Serum Ferritin 2,800 ng/mL (N: 10-200 ng/mL) WBC 5.8 x 10^9/L MCV 86 fL MCH 26 pg MCHC 32% Prussian Blue stain of bone marrow aspirate indicates markedly elevated iron stores. These laboratory results are MOST consistent with which of the following conditions? Please select the single best answer Sideroblastic anemia Anemia of chronic disease Hemochromatosis Megaloblastic anemia

Hemochromatosis Hemochromatosis is the most common form of iron overload disease. Characteristic findings are elevations in serum iron and ferritin. Positive Prussian Blue stain of the bone marrow indicates elevated iron (hemosiderin) stores. Sideroblastic anemia occurs when there is decreased production of protoporphyrin, which is necessary for the synthesis of heme. Patients with sideroblastic anemia have increased iron deposits in the nucleated red cells in the bone marrow. Iron accumulates in the mitochondria of these nucleated red cells and results in "ringed sideroblasts. Anemia of chronic disease, also known as anemia of chronic inflammation, is caused by increased production of Hepcidin, an acute-phase protein that regulates iron absorption. During inflammation, Hepcidin sequesters iron from the intestine and stores it in macrophages, preventing iron from reaching the plasma where it can be delivered to developing RBCs, thus causing anemia. Patients with anemia of chronic disease have decreased serum iron and total iron-binding capacity. Megaloblastic anemia is caused by impaired DNA synthesis, which is due to deficiencies in Folate or Vitamin B12. Patients with megaloblastic anemia have macrocytic RBCs in the peripheral blood and giant nucleated red cells (megaloblasts) in the bone marrow. Iron studies in these patients are normal.

Of the dimorphic fungal species listed below, which has the slowest rate of growth in primary culture? Please select the single best answer Coccidioides immitis Histoplasma capsulatum Sporothrix schenckii Blastomyces dermatidis

Histoplasma capsulatum Histoplasma capsulatum will take the longest time for mycelial forms to mature in primary culture. On average, it will take seven to fifteen days before colonies appear but may take as long as 8 weeks. Clinical manifestations of histoplasmosis infections include pulmonitis, mediastinitis, pericarditis, and mucocutaneous lesions. Sporothrix schenckii will usually appear in culture more rapidly than the other species, appearing in as little as 24-48 hours and maturing within seven days. Coccidioides immitis will generally appear in about five days. Blastomyces dermatitidis usually appear in about five to fourteen days.

A completely sickled cell (drepanocyte) is most commonly seen in which of these conditions? Please select the single best answer Homozygous HbSS Heterozygous HbSA Double heterozygous HbSC Hb S with beta thalassemia

Homozygous HbSS Truly sickled cells are a result of a homozygous HbSS state. Heterozygous HbSA or Sickle cell trait patients typically do not exhibit any red blood cell abnormalities on the peripheral smear. In double heterozygous HbSC, sickle cells are rarely seen on the peripheral smear. Typically more than half the erythrocytes are target cells. Plump sickle forms may also be noted as well. Hb S with beta-thalassemia is characterized by microcytes and 4+ target cells on the peripheral smear.

The cestodes or tapeworms can be identified by the unique appearance of their eggs. Examine the image at the right and consider the following choices. Each is a correct match of the egg with its species, EXCEPT: Please select the single best answer Image A = Echinococcus granulosus Image B =Diphyllobothrium latum Image C = Hymenolepis nana Image D = Taenia spp.

Image A = Echinococcus granulosus Image A represents the egg of Dipylidium caninum, not Echinococcus granulosus. The egg packets of D. caninum are large and irregular and contain 15-25 globular eggs, with an oncosphere and 6 hooklets. The eggs of E. granulosus are hexacanth and resemble those of Taenia spp. Image B shows the egg of Diphyllobothrium latum which is unembryonated, with a thin shell and indistinct operculum. Cleavage fills the entire egg. Image C represents the egg of Hymenolepis nana, which is hexacanth or lancet-shaped with six hooklets. It is round to oval with a thin, smooth membrane and an outer shell. There is a clear space between the membrane and shell and 4-8 filaments emerge from its inner membrane. Image D represents the eggs of Taenia species, T. solium, and T. saginata as the eggs are indistinguishable. The eggs have a dark brown shell that surrounds the oncosphere with a radially striated shell and 6 hooklets. The gravid proglottids must be examined to distinguish these two Taenia species.

Eggs of Taenia species

Image D represents the eggs of Taenia species, T. solium, and T. saginata as the eggs are indistinguishable. The eggs have a dark brown shell that surrounds the oncosphere with a radially striated shell and 6 hooklets. The gravid proglottids must be examined to distinguish these two Taenia species.

This is an Echinococcus granulosus hydatid cyst. Identify the object(s) that arrow "B" is pointing to. Please select the single best answer Immature scolices Cyst wall Germinal tissue layers Daughter cyst

Immature scolices B is pointing specifically to the immature scolices inside a daughter cyst. "A" points to the entire daughter cyst, while "C" points to the cyst wall and "D" points to the germinal layer. Humans are accidental hosts in the life cycle of this parasite. Even though each immature scolex has the ability to form an adult worm when developed, there is no mechanism for them to complete their life cycle in the outside environment when humans become involved. Hydatid cysts form in human tissue where they may cause intense pain. Rupture of such a cyst may result in serious complications including death.

Which of the following tests confirms the presence of Bence-Jones proteinuria: Please select the single best answer Protein electrophoresis Sulfosalicylic acid precipitation Cryoprecipitation Immunoelectrophoresis

Immunoelectrophoresis Immunoelectrophoresis is used to detect the presence of Bence-Jones proteins. Immunoelectrophoresis is used to help detect, diagnose, and monitor the course and treatment of conditions associated with abnormal proteins (such as Bence-Jones), including Multiple Myeloma, Waldenstrom's macroglobulinemia, and a few other related diseases.

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? The correct answer is highlighted below 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.

How does hydroxyurea aid in the treatment of sickle cell disease? Please select the single best answer Acts as an analgesic in pain management. Prevents sickle cells from clumping together. Induces increased production of HbF. Reduces the number of sickle cells that form.

Induces increased production of HbF. Hydroxyurea induces increased production of HbF. Most sickle cell patients who have increased levels of HbF experience milder forms of the disease than do patients with normal or low levels of HbF. Therefore, the focus of molecular treatments for sickle cell disease is to increase fetal hemoglobin (HbF). Anti-inflammatory agents are given to serve as an analgesic in pain management for sickle cell patients. Nitric oxide treatment prevents sickle cells from clumping together. Clotrimazole is an over-the-counter antifungal medication. This drug prevents water loss from the red blood cells, which helps prevent the formation of sickle cells.

Which two intestinal protozoans lack peripheral chromatin in their cyst forms? Please select the single best answer Entamoeba coli & Entamoeba hartmanni Iodamoeba bütschlii & Endolimax nana Entamoeba histolytica & Entamoeba dispar Entamoeba coli & Endolimax nana

Iodamoeba bütschlii & Endolimax nana The presence or absence of peripheral chromatin as well as its arrangement, when present, serve as key identifying nuclear characteristics of Entamoeba spp., Iodamoeba bütschlii & Endolimax nana. Iodamoeba bütschlii & Endolimax nana show no peripheral chromatin. Entamoeba coli show peripheral chromatin as coarsely granular and may be clumped. Entamoeba hartmanni show fine granules evenly distributed on the membrane. Entamoeba histolytica & Entamoeba dispar have peripheral chromatin present with fine, uniform granules that are evenly distributed.

Chloroquine diphosphate can be used in blood banking for which of the following methodologies? Please select the single best answer To remove antibody bound to red cells so that cells can be further tested To remove a specific antibody in serum or plasma To remove ABO antigens from cells To remove Rh antigens from cells

To remove antibody bound to red cells so that cells can be further tested Chloroquine diphosphate (CDP) The most common use of chloroquine diphosphate in the blood bank laboratory is to remove IgG bound to red cells that were detected from a positive DAT. These treated RBCs can then be used for autologous adsorption and/or to determine the patient's RBC phenotype.

A characteristic of a good cardiac biomarker is that: Please select the single best answer It can be detected only if it is present in a HIGH concentration in the peripheral blood. It can be detected even if it is present in a LOW concentration in the peripheral blood. It can be detected only if it is present in a HIGH concentration in urine. It can be detected even if it is present in a LOW concentration in urine.

It can be detected even if it is present in a LOW concentration in the peripheral blood. The smallest cardiac damage releases intracellular proteins from the myocardium and a good biomarker should be detected by laboratory testing even if it is in very low concentrations in peripheral blood. The ideal biomarker for myocardial injury should: Be heart specific and not found in other tissues. Be released rapidly from the heart into the peripheral circulation. Persist in the peripheral circulation for several days. Be detected by laboratory testing even if it is in low concentration in peripheral blood. Be rapidly detected in the laboratory

Using molecular methods to identify organisms can provide GREATER specificity when compared to phenotypic methods. Which of the following organisms would molecular methods not be beneficial over phenotypic methods in identification? Please select the single best answer Corynebacterium and related genera Klebsiella species Nocardia and related genera Dimorphic mycologic pathogens

Klebsiella species Klebsiella species is the correct answer because Enterobacteriaciae such as Klebsiella can still be reliably and easily identified by phenotypic (biochemical) methodologies. Corynebacterium and related genera, Nocardia and related genera, and dimorphic mycologic pathogens are incorrect answers because molecular techniques such as sequencing methods are relied upon for the definitive identification. Molecular techniques provide a higher sensitivity over phenotypic methodologies because molecular techniques can assist in identifying fastidious or slow growing organisms, non-culturable organisms, and non-viable organisms.

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? Please select the single best answer 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.

Which one of these Lewis blood group system phenotypes usually produces anti-Lea? Please select the single best answer Le(a+b+) Le(a+b-) Le(a-b+) Le(a-b-)

Le(a-b-) This antibody can occur almost exclusively in the serum of Le(a-b-) individuals and can occur without red blood cell stimulus. It is typically found as a clinically insignificant, naturally occurring IgM antibody. Phenotypes other than Le(a-b-) rarely produce the corresponding antibody.

This suspicious form was recovered from a bone marrow biopsy and measures 4 µm in length. What is the MOST likely identification of this organism? Please select the single best answer Trypanosoma epimastigote Trypanosoma trypomastigote Leishmania epimastigote Leishmania amastigote

Leishmania amastigote Human hosts are injected with promastigotes when the sand fly takes a blood meal. Within the human host, they migrate to the RE system (bone marrow, spleen, liver) or to macrophages of the skin or mucous membranes and transform to amastigotes. Trypanosoma epimastigote is the infective stage that is introduced into the human host by the tsetse fly but is not often observed in clinical samples. Trypanosoma trypomastigote has a posterior flagellum, delicate undulating membrane, the posterior kinetoplast, central nucleus, and measures 15 - 30 µm in length. There is no Leishmania epimastigote form.

A variety of additives are used in blood collection tubes. Which of the following additives prevents clotting by inhibiting thrombin and thromboplastin? Please select the single best answer EDTA Gel Lithium or sodium heparin Sodium fluoride

Lithium or sodium heparin Lithium/sodium heparin is an additive used to prevent clotting by inhibiting thrombin and thromboplastin. It is found in green and light green tubes. EDTA prevents blood from clotting by binding calcium, which in turn inhibits the coagulation cascade. EDTA is found in 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. Sodium fluoride is found in gray top tubes and its purpose is to inhibit glycolysis (metabolism of glucose by red blood cells).

The appropriate media for the isolation of anaerobic bacteria from any source would normally include all of the following except: Please select the single best answer CDC blood agar MacConkey agar Phenylethyl alcohol agar (PEA) Kanamycin-vancomycin-laked blood agar (KVLB)

MacConkey agar In order to assess anaerobes in clinical specimens, the best media to use are those that have not been exposed to oxygen. Typically, all cultures include one type of anaerobic blood agar, such as CDC agar, that has been prereduced to remove any molecular oxygen that could inhibit the growth of anaerobes. Phenylethyl alcohol agar (PEA) can be used in anaerobic cultures because the media supports the growth of almost all obligate anaerobes (gram-positive and gram-negative) and gram-positive facultative anaerobes. Kanamycin-vancomycin-laked blood agar (KVLB) supports the growth of anaerobic gram-negative bacilli such as Bacteroides and Prevotella species. MacConkey agar is a selective and differential agar that is used for aerobic gram-negative bacilli, such as differentiating the Enterobacteriaceae family. MacConkey agar does not support the growth of anaerobic bacteria and should not be used for anaerobic cultures.

The education coordinator for the hospital is required to develop competency assessment activities for the POCT providers in the emergency department. What document may serve as a guideline for specific steps to be included in the assessments? Blank log sheets Completed QC records Manufacturer's instructions Safety data sheets (SDSs)

Manufacturer's instructions Manufacturer's instructions provide step-by-step directions for completing testing or operating the instrument. These instructions may serve as a guideline for steps that must be included when competency is assessed.

The presence of an increased number of hypersegmented neutrophils in the peripheral blood, as shown in this image, is an indication of which of the following conditions? Please select the single best answer Preleukemia Megaloblastic anemia Aplastic anemia Myeloproliferative disorder

Megaloblastic anemia Hypersegmentation of neutrophils (see image) provides strong morphologic evidence for megaloblastic hematopoiesis. When such cells with six or more lobes are present in the peripheral blood, assays for vitamin B-12 and folate are indicated. These hypersegmented neutrophils are also usually macrocytic as the disruption in normal maturation has resulted in fewer nuclear divisions. In the bone marrow, finding greater than 5% neutrophils with five lobes or greater, or more than 50% with four lobes or greater is evidence that megaloblastic myelopoiesis is to be ruled out. Preleukemia and myeloproliferative disorders are not characterized by hypersegmented neutrophils. Aplastic anemia is characterized by pancytopenia.

Which of the following cells is the most common nucleated cell in normal adult bone marrow? Please select the single best answer Myeloblast Promyelocyte Myelocyte Metamyelocyte

Metamyelocyte Of the given choices, metamyelocytes are the most abundant form seen in a normal bone marrow. Reference interval is 3-20% Myeloblast reference interval is 0-3%. Promyelocyte reference interval is 1-5%. Myelocyte reference interval is 6-17%.

All of the terms below are a measure of central tendency, EXCEPT: Please select the single best answer Mean Molarity Median Mode

Molarity Molarity is the numbers of moles of a solute per liter of solution. This is not a measure of central tendency. Mean is the average of a group of numbers. Median is the central number in a set of numbers when the numbers are arranged in sequential order. Mode is the number that occurs most frequently in a group of numbers.

The tiny colonies growing on chocolate agar after 3 days of incubation, as illustrated in the left plate in the upper 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 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. Reactions for nitrate reduction and iron uptake were negative. A distinctive characteristic was the antibiotic resistance to Ciprofloxacin (left upper strip) and Polymyxin B susceptibility (vertical strip) in the lower photograph. From these observations, select the identification of this isolate. Please select the single best answer Mycobacterium chelonae Mycobacterium fortuitum Mycobacterium gordonae Mycobacterium scrofulaceum

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 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 Mycobacteria species from M. chelonae. Susceptibility testing is not required to make this separation.

A patient's coagulation mixing study results are shown below after an initially prolonged aPTT result. Initial aPTT 63 sec. (normal range 21-34 seconds) Immediate aPTT mixing study 26 sec Incubated aPTT mixing study 65 sec. Has the aPTT been corrected by the mix? Is a factor deficiency or a coagulation inhibitor the more likely cause of the patient's prolonged aPTT? Please select the single best answer Corrected, Factor Deficiency Corrected, Coagulation Inhibitor Not Corrected, Factor Deficiency Not Corrected, Coagulation Inhibitor

Not Corrected, Coagulation Inhibitor These results show that no correction has taken place; initially, it appears that the aPTT corrects. However, after the incubation time, the aPTT is again prolonged. This means that a weak or slow-acting coagulation inhibitor may be present and an extended incubation time is needed to reveal the inhibitor. These results are characteristic of a factor VIII inhibitor, for example.

A2B is suspected when a patient's ABO typing has the following results: Please select the single best answer Patient's red cells forward types as AB with anti-A1 present in the patient's serum. Patient's red cells forward types as A with anti-A1 and anti-B present in the patient's serum. Patient's red cells do not react with either Anti-A nor Anti-B, and anti-A1 and anti-B are present in the patient's serum. Patient's red cells forward types as A with a mixed field reaction of the patient's red cells with Anti-A, and anti-B detected in the patient's serum.

Patient's red cells forward types as AB with anti-A1 present in the patient's serum. A2B individuals may produce anti-A1. 22-35% of A2B individuals have anti-A1 in their serum. A2B individuals forward type as AB, and may demonstrate anti-A1 in their serum. A2 individuals forward types as A, and may demonstrate anti-A1 in their serum. A2 individuals will have anti-B in their serum. 1-8% of A2 individuals have naturally occurring anti-A1 in their serum. A patient whose red cells do not react with either Anti-A nor Anti-B, and have anti-A1 and anti-B are present in the their serum is type O. The A3 subgroup RBCs will have a mixed field pattern of agglutination with anti-A reagents.

Which of the following is considered a macrocytic anemia? Please select the single best answer Cooley's anemia Iron deficiency anemia Pernicious anemia Polycythemia vera

Pernicious anemia Pernicious anemia is a megaloblastic anemia associated with macrocytic, normochromic red blood cells. Cooley's anemia is another term for beta-thalassemia major, which is a microcytic, hypochromic anemia. Iron deficiency anemia is also a microcytic, hypochromic anemia. Polycythemia vera is not an anemia, but a myeloproliferative disorder characterized by increased amounts of red blood cells, white blood cells, and platelets.

Illustrated in the top image is a 4-day growth of a dark brown, entire colony with a narrow outer white zone. The surface mycelium is glabrous and finely granular. As this colony is not specific, the fungal species identification must be made on stained mounts prepared from the surface of the mycelium. In the lactophenol blue mount shown in the bottom photomicrograph is the characteristic sac-like structure, a pycnidium, within which are contained small spiral, hyaline, one-celled conidia. Select the name of the fungal species represented in these photographs. Please select the single best answer Chaetomium species Phoma species Ulocladium species Culvularia species

Phoma species Phoma species is the correct response. Although the colony morphology is not distinctive, the rather smooth to peppery appearance of the surface mycelium indicate that hyphae and not conidia are present. The identification can be made microscopically by observing the large, smooth walled sac-like structure that is known as a pycnidium. Within the pycnidia are small, spherical, hyaline one-celled conidia. Chaetomium species contain flask-shaped perithecia which, in contrast to those of Phoma species, are large and distinct due to extension of hair-like extensions. Ascospores are released within the perithecium. Ulocladium species produce colonies that are rapidly growing, ranging from gray, olive-green, or black. Ulocladium species contain multi-celled, angular, cross-walled conidia on sympodial conidiophores. Curvularia species produce colonies that are rapidly growing, cottony, and gray to black. Microscopically, multi-celled, crescent shaped conidia with 3-5 unequally-sized cells are seen on conidiophores.

What procedure utilizes leukapheresis to collect the buffy coat from whole blood? Please select the single best answer Photopheresis Plasmapheresis Therapeutic apheresis Erythrocytapheresis

Photopheresis Photopheresis utilizes leukapheresis to collect the buffy coat layer from whole blood. These cells are treated with 8-methoxypsoralen, exposed to ultraviolet A light and then reinfused into the patient. Photopheresis has been shown to be efficacious and has been approved by the Food and Drug Administration for the treatment of cutaneous T-cell lymphoma. Plasmapheresis is the removal and retention of the plasma, with return of all cellular components to the patient. Therapeutic apheresis (TA) involves the removal of a specific blood component, with return of the remaining blood constituents to the patient. However, with TA the component being removed is considered pathological or contributing to the patient's underlying disease state. Erythrocytapheresis, or red cell exchange, removes a large number of red blood cells from the patient and returns the patient's plasma and platelets along with compatible allogeneic donor red blood cells.

Which finding best distinguishes immune hemolytic anemia from other hemolytic anemias? Please select the single best answer Rouleaux Positive DAT Splenomegaly Increased erythrocyte count

Positive DAT In the group of disorders referred to as immune hemolytic anemias, erythrocytes are destroyed too early by an immune-mediated process that results from antibodies, complement, or both attaching to the red cell membrane. The presence of immune hemolytic anemia is confirmed by a positive DAT (direct antiglobulin test). Rouleaux is the formation of red cells that are stacked and appear like a stack of coins. This is a characteristic finding in multiple myeloma. Splenomegaly, or an enlarged spleen, may be found in Gaucher's disease or in polycythemia vera. It is not found in immune hemolytic anemia. Increased erythrocyte count is not a finding in immune hemolytic anemia.

Which of the following is an expected or common laboratory finding in patients with hereditary hemochromatosis (HH)? Please select the single best answer 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. 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 elevated serum ferritin.

All of the following conditions would be associated with an increased level of alpha-fetoprotein, EXCEPT? Please select the single best answer Prostate Cancer Hepatocellular Carcinoma Viral Hepatitis Testicular Tumors

Prostate Cancer AFP is not found in increased levels in patients with prostate cancer. PSA, or prostate-specific antigen, is commonly used to screen for prostate cancer, not AFP. Hepatocellular carcinoma, viral hepatitis, testicular tumors, and pancreatic cancer are all associated with increased levels of AFP. In addition, liver cirrhosis and gastric cancers can also have an associated increased AFP level. AFP is one of the oncofetal proteins which are produced in high concentration during fetal life. The fetal yolk sac and liver produce AFP. Oncofetal proteins usually disappear or are reduced to very low concentrations after birth. Increased alpha-fetoprotein levels in adults are usually associated with hepatocellular carcinoma, a tumor marker in this population.

Which adsorption technique removes cold (IgM) antibodies, particularly anti-I specificities? Please select the single best answer Cold autoadsorption Warm autoadsorption Differential (allogeneic) Rabbit erythrocyte stroma (RESt)

Rabbit erythrocyte stroma (RESt) RESt removes cold (IgM) antibodies, particularly anti-I specificities. However, it may adsorb anti-B and other IgM antibodies. Cold autoadsorption uses patient red cells to remove cold autoantibodies to determine whether alloantibodies are present. Warm autoadsorption uses patient red cells are used to remove warm autoantibodies to determine whether alloantibodies are present. Allogeneic adsorption uses known phenotyped red cells to separate specificities: 1) warm autoantibodies from alloantibodies 2) alloantibodies with several specificities.

What function in the body does GGT have? Please select the single best answer Transfer of gamma-glutamyl peptides amino acids, water, and other peptides Transfer of amino acid residues to other compounds Transfer of gamma-glutamyl peptides to cholesterols Transfer of water from amino acids to gamma-glutamyl

Transfer of gamma-glutamyl peptides amino acids, water, and other peptides The correct answer is the transfer of gamma-glutamyl peptides to amino acids, water, and other peptides. GGT does not transfer amino acids to other compounds (think AST and ALT) or water as it is specific for gamma-glutamyl. Therefore, cholesterols do not have gamma-glutamyl peptides attached to them.

What RBC morphology on a Wright-stained smear may indicate the presence of an unstable hemoglobin? Please select the single best answer Acanthocytes Codocytes Schistocytes Xerocytes

Schistocytes Though not diagnostic for alpha thalassemia, schistocytes (fragmented RBCs) indicate that there is one of several forms of red blood cell destruction occurs. When unstable hemoglobin is formed, such as Hemoglobin H in alpha thalassemia intermedia, macrophages may remove the precipitated tetramers out of the cell, leaving it appearing "bitten." These "bite" cells are schistocytes. Acanthocytes, sometimes called spur cells, have a few membrane projections of different sizes. Acanthocytes may be seen in acute liver disease. Codocytes, or target cells, have hemoglobin concentrated in the center and the periphery of the red cell, forming a target shape. Codocytes are seen in thalassemia and many hemoglobinopathies, such as Hemoglobin C disease. Xerocytes are dehydrated red cells and have a dark side with concentrated hemoglobin and a lighter side with less hemoglobin. Xerocytes are seen in a genetic disease, hereditary xerocytosis. The red cells in this disorder are unable to regulate the flow of cations in the cell, resulting in dehydration of the cell.

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, one 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.

The upper image is a 4 day old colony grown on Sabouraud's Dextrose agar, recovered from a bacterial culture that was considered to be a "contaminant". The lower image is a high power image of a methylene-blue stained mount prepared from the surfaces of the colony. With these observations, select the fungus genus from the multiple choices as listed. Please select the single best answer Sepedonium Scedosporium Beauveria Chrysosporium

Sepedonium Sepedonium is the intended response. The colony as illustrated is non-specific, with a fine silky surface and a light gray-pink pigmentation with shallow radiating rugae extending peripherally. Distinctive for the identification is the microscopic observation of spherical to pyriform shaped bluntly spiked conidia borne singly from slender conidiophores. These resemble the larger spiked macroconidia of the dimorphic fungus, Histoplasma capsulatum, the time of growth of which is much longer than that of Sepedonium sp., and that can be converted to a yeast form upon incubation at 35-37° C. Scedosporium colonies are also rapidly growing with a low cottony surface mycelium, with the centers of older colonies having a distinct "house mouse gray" pigmentation. Clavate, smooth walled microconidia produced at the tips of short to long often branched conidiophores. The microconidia of Scedosporidium have a dark brown pigmentation that is responsible for the "house mouse" gray appearance on the surface of the colonies. 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. 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.

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? Please select the single best answer Septicemia Viral infection Tuberculosis Active allergies

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.

All of the following should be done when centrifuging specimens, EXCEPT? Please select the single best answer Specimens without anticoagulant should sit for 30 minutes before centrifugation. Specimens with anticoagulant should sit for 20 minutes before centrifugation. Cap all tubes for centrifugation. Allow the centrifuge to come to a complete stop by itself before opening it.

Specimens with anticoagulant should sit for 20 minutes before centrifugation. Specimens with anticoagulants can be spun immediately. There is no reason to delay. Specimens without anticoagulants should sit at least 30 minutes prior to centrifugation to allow for complete clotting of the blood. Proper centrifugation procedure includes making sure all tubes are capped during centrifugation and letting the centrifuge stop completely by itself before opening it.

This antinuclear antibody (ANA) pattern is characterized by granular staining in the nuclei of the interphase cells (a). There is also an absence of staining in the chromosomal area of the metaphase mitotic cells (b). The slide is viewed using fluorescent microscopy. Which pattern is this? Please select the single best answer Homogeneous Speckled Nucleolar Centromere

Speckled 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. The image shown displays the features of a speckled ANA pattern: granular/speckled staining in the nuclei of the interphase cells (a) and absence of staining in the chromosomal area of the metaphase mitotic cells (b). The nucleoli do not stain; thus, the pattern is not nucleolar. A homogeneous pattern would show uniform staining of the nuclei in the interphase cells and presence of staining in the chromatin of the dividing cells. The centromere pattern is characterized by many discrete speckles in both the nuclei of interphase cells and the chromatin of dividing cells.

A Staphylococcus species recovered from blood culture was found to produce acid from sucrose and maltose and showed alkaline phosphatase activity. Staphylococcus was also coagulase-negative. The same organism was also found in culture from the central line tip. The most likely identification is: Please select the single best answer Staphylococcus saprophyticus Staphylococcus schleiferi Staphylococcus epidermidis Staphylococcus aureus

Staphylococcus epidermidis Staphylococcus epidermidis is a normal flora organism on the skin, but a common cause of infections from medical devices. The organism can produce biofilms on catheters and other medical devices. The biofilm is a complex interaction between the device, host, and bacteria. A large number of organisms may aggregate in the biofilm and then be shed into the bloodstream or other nearby sites depending on the biofilm placement. Sometimes in blood cultures, Staphylococcus epidermidis can be seen as a contaminant from the skin during collection. However, by the organism's presence in both the blood and line cultures, this can be determined as an infection from the central line. S. epidermidis also produces acid from sucrose and maltose and has alkaline phosphatase activity, important characteristics included in most algorithms and identification systems. They are also coagulase-negative. Staphylococcus saprophyticus is coagulase-negative, and does produce acid from sucrose and maltose, but is alkaline phosphatase negative. These organisms are also typically found in the urinary system as a cause of urinary tract infections, specifically in women, and rarely found on the skin or mucous membranes. Staphylococcus schleiferi is also coagulase-negative Staphylococcus but it does not produce acid from sucrose and maltose. It is alkaline phosphatase positive. These organisms are also typically considered contaminants or causes of opportunistic infections. Staphylococcus aureus is a coagulase-positive Staphylococcus and would be eliminated based on that result alone. S. aureus, however, is alkaline phosphatase positive as well as produces acid from sucrose and maltose.

Illustrated in the top photograph is the 3-day growth of a colony on Sabouraud's dextrose (SAB) agar incubated at 35 C. 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. Please select the single best answer Curvularia species Ulocladium species Alternaria species Stemphylium species

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 macroconidia 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.

The bacterium in the image to the right is also referred to in the quote below, what is the identification of this bacteria? "If a pregnant woman be attacked by erysipelas of the womb, it is fatal." - Hippocrates Please select the single best answer Streptococcus pyogenes Streptococcus agalactiae Listeria monocytogenes Brucella abortus

Streptococcus pyogenes The rapidly fatal disease of pregnant women in older times, called erysipelas or "Puerperal Fever", is shown by Semmelweis to be transmitted from patient to patient in birthing suites, via the unwashed hands of the nurses, physicians, and midwives. Streptococcus pyogenes (group A streptococci) produces small, translucent colonies surrounded by a wide zone of beta hemolysis, as shown in the upper photograph and gram-positive cocci in chains (lower photomicrograph). Group A streptococcus is the most universal agent causing this syndrome, although other bacterial species such as E. coli and C. perfringens may from time to time be involved. Group B streptococci (S. agalactiae), although an agent of infection during childbirth, is more likely to severely affect the neonate than the mother, even though infrequent cases of puerperal sepsis can occur. Listeria monocytogenes also can be involved in abortion, maternal endometritis, and neonatal meningitis; however, the mode of transmission is usually through ingestion of contaminated foods and not via the mechanism described here. Brucella abortus also can result in abortion and perinatal infections; however, acute fevers are not usually experienced, rather a more chronic, low-grade, undulating pattern is more common.

Which of the following is the best media for recovery and presumptive identification of Clostridioides (formerly Clostridium) difficile in suspected cases of pseudomembranous colitis? Please select the single best answer CDC anaerobic blood agar Columbia agar with 5% sheep blood Cycloserine-cefoxitin fructose agar (CCFA) Phenylethyl agar

Sucrose Sucrose is not a reducing sugar since the anomeric carbon of both monosaccharides (glucose and fructose) are part of the glycosidic bond, preventing the anomeric carbon of fructose (and therefore its ketone group) from being free and reducing other compounds. Lactose, Glucose and Ribose are all reducing sugars since their anomeric carbons and aldehyde groups are all free to reduce other compounds.

A mother's serologic results are shown above. Her newborn types as group A Rh-positive with a (1+) positive direct antiglobulin test (DAT). Which of the following investigative tests would be most useful to resolve the cause of the positive DAT and should be done FIRST? Please select the single best answer Test an eluate prepared from newborn's red cells against an antibody identification panel by IAT. Test newborn's plasma against group A1 red cells and group O antibody screen cells by IAT. Test newborn's plasma against mother's red cells by IAT. Test newborn's plasma against father's red cells by IAT.

Test newborn's plasma against group A1 red cells and group O antibody screen cells by IAT. The mother is group O Rh positive with a negative antibody screen and the infant is group A Rh positive. Results are consistent with a possible case of ABO HDFN. ABO HDFN is nearly always limited to A or B infants of group O mothers with potent anti-A,B. The most useful follow-up would be to test the infant's plasma against A1 red cells and group O antibody screen cells (as a control), expecting only the A1 cells to be positive (due to the mother's anti-A,B because she is group O) if the DAT was due to ABO incompatibility.

Which one of the following parasites is the causative agent of Katayama fever? Please select the single best answer Schistosoma mansoni Strongyloides stercoralis Enterobius vermicularis Taenia saginata

The correct answer is Schistosoma mansoni Schistosomes are the causative agent of Katayama fever. The eggs of this organism may be readily identified by their large size, characteristic shape, and the location of a species-specific spine near the posterior end. The name schistosome was developed based on the appearance of the adult male that has a genital groove that serves as the receptacle for the female during copulation. Strongyloides stercoralis larva is sometimes referred to as the threadworm due to its appearance as a twisted piece of thread. Enterobius vermicularis is often called a pinworm due to its sharply pointed posterior end. Taenia saginata is also known as a beef tapeworm as it is found in beef.

Dipylidium caninum

The egg packets of D. caninum are large and irregular and contain 15-25 globular eggs, with an oncosphere and 6 hooklets.

The qualitative differences between A1 and A2 phenotypes includes all of the following EXCEPT: Please select the single best answer The formation of anti-A1 in A subgroups. The amount of transferase enzymes. The length of the precursor oligosaccharide chains. The lack of agglutination of patient red cells with anti-A reagent.

The lack of agglutination of patient red cells with anti-A reagent. Qualitative differences for A1 and A2 phenotypes include the following: differences in the precursor oligosaccharide chains (in length and complexity of branching), small differences in transferase enzymes (decreased in A2 subgroup), and the formation of anti-A1 in the serum of A2 phenotype individuals. Both A1 and A2 patient red cells react with the anti-A reagent. Dolichos biflorus or anti-A1 lectin reagent is used to differentiate between A1 and A2 phenotypes. This lectin reagent agglutinates with A1 patient red cells but does NOT agglutinate with A2 patient red cells.

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? Please select the single best answer 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.

Which one of the following is the correct definition of isoelectric point (pI)? Please select the single best answer Buffer formation of a positively charged ionic cloud that can affect the migration of the negative ionic cloud of the sample The ability of a molecule to have both negatively and positively charged groups The pH where a molecule has a net charge of zero The movement of charged particles in an electrical field

The pH where a molecule has a net charge of zero A molecule that has both negatively charged groups and positively charged groups is described as amphoteric. These charges can be changed by changing the pH of the solution. The pH where there is an equal number of positive and negative charges is the isoelectric point, that is the molecule has a net charge of zero.

A chemical reaction that is utilized by many different analytical methods involves: Please select the single best answer Fluorometry Glucose oxidase The reduction of NAD to NADH UV spectrophotometry

The reduction of NAD to NADH The reduction of NAD to NADH is a chemical reaction that is utilized by many different analytical methods. In addition, several different analytical methods can use this method because it is not a light-producing dependent reaction. Fluorometry is an analytical method that is dependent on analytes that have the ability to fluoresce. Glucose oxidase is an enzymatic glucose oxidase method used to measure the amount of glucose present in a sample. UV spectrophotometry is an analytical method dependent on the light-producing ability of analytes present in the sample.

A prothrombin time (PT) specimen was collected at an outpatient clinic and will not be picked up by the testing laboratory's courier until several hours later. How should the specimen be stored until it is picked up by the courier? Please select the single best answer The specimen should be centrifuged right away and stored in the refrigerator at 4° C until is picked up the courier. The specimen should be frozen immediately and kept there until is tested. The tube should remain unopened and be kept at room temperature (20°-25° C). The specimen should be protected from light.

The tube should remain unopened and be kept at room temperature (20°-25° C). Blood collected for a prothrombin time PT test that will be completed within 24 hours of collection should remain uncentrifuged in an unopened tube. Room temperature storage (20° - 25° C) is recommended. Temperatures between 2° - 4° C may result in cold activation of factor VII that would alter the PT result. The tube should not be opened to remove the plasma before testing if the test will be completed within 24 hours of collection. Plasma should be removed and frozen at -20° C or lower if the PT test is not completed within 24 hours. Whole blood should never be frozen because the red cells will lyse, and the PT test result would be drastically altered. The specimen does not require protection from light.

How would you describe the arrangement of RBCs on this slide? Please select the single best answer Artificial rouleaux Autoagglutination True rouleaux Normal RBC morphology

True rouleaux This field shows an example of true rouleaux. Notice that most of the red cells seen in the field are stacked together like coins. Four or more cells make up each formation in this slide, leaving much of the field empty of cells (increased white space). Increased protein in patients with rouleaux may stain the background blue. Artificial rouleaux occurs in the thicker part of the slide. When examining a peripheral blood smear, you should be viewing the red cells in an area where the RBCs are just touching each other in the "feathered edge" of the slide. Autoagglutination can occur when a patient develops a cold agglutinin, an autoantibody that reacts when the red cells are exposed to cold temperatures. The agglutination may be seen on a slide as random clumps of red cells. Warming the EDTA blood sample to 37° C will cause the agglutination to disappear. Normal RBCs should not be clumped together in the feathered edge of the slide.

A cerebrospinal fluid sample was taken from an inpatient with severe neurological symptoms. The image shows a field from a cytospin preparation from this patient's fluid. What findings are present in this field? Please select the single best answer Blast cells Mesothelial cells Choroid plexus clump Tumor cells

Tumor cells This is a cytospin from the CSF of a patient with disseminated retinoblastoma demonstrating a large tumor cell clump with an occasional mitotic figure. Tumor cells should be reported for this sample. This sample should be sent for pathologist review prior to reporting these findings. Blast cells may appear in CSF and will look similar in CSF as they do in peripheral blood. Mesothelial cells form a layer of mesodermal cells in the pericardial sac. They are found in pleural and peritoneal fluids. Choroid plexus cells in a clump are neuroepithelial tissue cells that usually appear in a sheet formation.

The type of hypersensitivity reaction associated with macrophage activation, cytokine-mediated inflammation is: Please select the single best answer Type I Anaphylactic (Immediate hypersensitivity) Type II Cytotoxic (Antibody mediated and antibody dependent, complement mediated hypersensitivity) Type III Immune complex mediated hypersensitivity Type IV Cell mediated hypersensitivity (T-cell dependent)

Type IV Cell mediated hypersensitivity (T-cell dependent) Type IV Cell-mediated hypersensitivity is associated with macrophage activation. Type IV is characterized by direct target cell lysis and cytokine-mediate inflammation. There are three defining characteristics of type IV hypersensitivity reactions: (1)Type IV delayed-type hypersensitivity involving antigen-sensitized T cells or particles that remain phagocytized in a macrophage and are encountered by previously activated T cells for a second or subsequent time. Delayed hypersensitivity is a major defense mechanism again various intracellular pathogens, including mycobacteria, fungi, and certain parasites. (2) Rejection of foreign tissue grafts, elimination of tumor cells bearing neoantigens. (3) Formation of chronic granulomas. Type I Immediate hypersensitivity is mast cell-derived mediators (vasoactive amines, lipid mediators, and cytokines). Cytokine-mediated inflammation involves eosinophils, neutrophils, and lymphocytes. Type I reactions can range from life-threatening anaphylactic reactions to milder manifestations associated with food allergies. Type II Antibody-mediated hypersensitivity is associated with complement and Fc receptor-mediated recruitment and activation of leukocytes (neutrophils and macrophages). Opsonization and phagocytosis of cells. Abnormalities in cellular function, e.g., hormone or neurotransmitter receptor signaling. Types II and III are initiated by the interaction between antibodies, except IgE and antigen. Three different mechanisms of antibody-mediated injury exist in type II reactions: (1) Antibody-dependent, complement-mediated cytotoxic reactions characterized by the interaction of IgG or IgM antibody with the cell-bound antigen. (2) Antibody-dependent, cell-mediated cytotoxicity that depends on the initial binding of specific antibodies to target cell surface antigens. (3) Antireceptor antibodies that disturb the functioning of receptors. Transfusion reactions are an example of an antibody-dependent, complement-mediated cytotoxic reaction. Hyperacute graft rejection is also an example of a Type II hypersensitivity reaction. Type III Immune complex-mediated hypersensitivity is associated with complement and Fc receptor-mediated recruitment and activation of leukocytes and tissue damage secondary to impaired blood flow. Type III reactions are caused by IgG, IgM, and possibly other antibody types. Immune complexes can cover a spectrum of biological activities, including suppression or augmentation of the immune response by interacting with T and B cells; inhibition of tumor cell destruction; and deposition in blood vessel walls, glomerular membranes, and other sites. These deposits interrupt normal physiologic processes because of tissue damage secondary to the activation of complement and resulting activities.

While working on fungal cultures, a tech encounters an organism that is orange/red in color. Immediately the tech suspects the organism is Rhodotorula species based on the color. To confirm this identification, which testing can be performed? The correct answer is highlighted below Urease and Inositol Germ Ink Oxidase

Urease and Inositol Urease and inositol testing can be used to confirm the isolation of Rhodotorula species. Rhodotorula species are urease positive and inositol negative. Germ tube testing is used to differentiate Candida albicans from other yeast, as Candida albicans is germ tube positive. The Germ tube test does not assist in the identification of Rhodotorula species. India ink testing is used to differentiate Cryptococcus species from other yeast by showing the capsules that surround the cells. This testing does not assist in the identification of Rhodotorula species. Oxidase testing is used for Gram-negative bacteria and not used for fungal isolates.

When performing an anti-human globulin (AHG) test, it is important to completely wash the red cells because: Please select the single best answer Washing eliminates concentrations of unbound antigens. Washing prevents elution of cell-bound antibody. Washing promotes false positive effects of rouleaux. Washing prevents neutralization of the anti-human globulin (AHG) serum.

Washing prevents neutralization of the anti-human globulin (AHG) serum. In the AHG test procedure, the source of antigen for potential reaction comes from red blood cells. Washing procedures that remove red blood cells or antigen from the testing system would invalidate any testing results. In a positive AHG test, antibody is bound to antigen after the incubation stage. Washing should not remove cell-bound antibody, nor would it prevent bound antibody from eluting from the antigen. The effects of rouleaux may be noted in test systems in which the protein content is high. Washing removes protein from the test system, so rouleaux is not a cause of false positive reactions in AHG testing. Inadequate cell washing will lead to unbound antibody remaining in the red cell suspension. This residual unbound antibody would be available to neutralize the AHG (Coombs serum), so it will not react with red blood cells (antigen) bound with antibody.

Diphyllobothrium latum

What parasite found in raw fish can produce vitamin B12 deficiency? The egg of Diphyllobothrium latum which is unembryonated, with a thin shell and indistinct operculum. Cleavage fills the entire egg.

When performing your mixing study, you aliquot your sample plasma and the pooled normal plasma to create your "mix." You then place the sample in a water bath to incubate for 90 minutes before running your new mixed sample. What is the problem with the steps involved in the procedure above? The correct answer is highlighted below You don't need to incubate your sample. You have forgotten to add a reagent. You have not run a PT or aPTT on the new mix before incubating. You have incubated too long.

You have forgotten to add a reagent. In this case, the step missing is the first run of the PT or aPTT test after the mix, but before the incubation step. The procedure is not missing a reagent as only the patient plasma and pooled normal plasma are involved in the mixing study procedure. The incubation time is correct, as it is recommended to incubate for 60-120 minutes.

Based on the following results obtained against a patient's red cells, what will the genotype look like in this example? Anti-C = 4+ Anti-c = 4+ Anti-E = 0 Anti-e = 4+ Anti-D = 0 The correct answer is highlighted below R0R0 rr r'r R1R2

r'r Based on the positive antigen results given, the most likely Fisher-Race phenotype is Ce/ce. The patient lacks D antigen and presents with c, e, and C antigens. It is necessary to convert between Wiener shorthand designation and Fisher-Race nomenclature to make this determination. For this case, the patient's Fisher-Race phenotype (Ce/ce) translates into r'r (Ce/ce). Alternatively, the lack of D antigen can be denoted as a lowercase 'd' in the Fisher-Race phenotype (i.e. dCe/dce). R0R0 converts into Dce/Dce indicating a presence of D antigen and a lack of C antigen. rr converts into dce/dce and does not indicate the presence of C antigen. R1R2 converts into DCe/DcE indicating the presence of both D and E antigens.