MLT

How many white blood cells (WBCs) would be considered normal for adult cerebrospinal fluid? Any number of WBCs is considered abnormal 0-5 WBCs/µL 6-10 WBCs/µL Up to 30 WBCs/µL

0-5 WBCs/µL Feedback In an adult, 0 - 5 WBC/µL is considered normal. Children will have slightly higher cell counts. Up to 30 WBC/µL is within normal limits for newborns. Lymphocytes account for 60 - 100% of these cells.

After an acute myocardial infarction (AMI), myoglobin levels will rise within 3 hours and peak at 8-12 hours. When will they return to normal? 10-20 hours 5-10 hour 3-4 days 18-30 hours

18-30 hours After an AMI, myoglobin is released into the bloodstream and peaks at about 8-12 hours. Since myoglobin is a small molecule that is filtered by the kidneys, levels return to normal at about 18-30 hours.

A sample of cerebrospinal fluid is diluted 1:100; the standard 9 squares of a hemocytometer are counted on each side for a total of 18 large squares. Side 1-- 186 nucleated cells counted Side 2-- 184 nucleated cells counted Total nucleated cells = 370 Using the standard hemocytometer formula shown on the right, what is the nucleated cell count per microliter (µL)? The correct answer is highlighted below 1.03 x 104 2.06 x 104 4.12 x 104 8.24 x 104

2.06 x 104 Feedback Using the formula on the right, Cells/µL = 370 x 100 / 18 x 0.1 Cells/µL = 37000 / 1.8 Cells/µL = 20556 or 2.06 x 104 The other numbers provided are all incorrect, as they either do not take all the nucleated cells into account, or are multiples of the correct answer. NEXT QUESTION

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: 1 SD 2 SD 3 SD 4 SD

3 SD Feedback 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. NEXT QUESTION

The sediment from a freshly collected urine specimen is examined microscopically. In addition to bacteria, what other finding from the list below would further indicate the presence of a urinary tract infection (UTI)? The correct answer is highlighted below 0 - 2 cuboidal epithelial cells/high power field (HPF) > 100 white blood cells (WBCs)/ HPF 10 - 20 squamous epithelial cells/ HPF Rare hyaline cast/ low power field (LPF)

> 100 white blood cells (WBCs)/ HPF Feedback The presence of white blood cells, especially in large quantities as in this case, is very indicative of urinary tract infections as the white cells are migrating to the urinary tract to fight the bacterial infection. Hematuria, increased pH, and proteinuria are also usually present in UTIs. NEXT QUESTION

The most common forms of hereditary sideroblastic anemia (SA) are due to which of the following? The correct answer is highlighted below A defective X-linked recessive gene. A defective Y-linked dominant gene. An amino acid substitution on the beta chain. An under production of alpha chains.

A defective X-linked recessive gene. Feedback The most common form of hereditary SA is due to an X-linked recessive gene. This rules out the second answer option.Hemoglobinopathies are, in many cases, due to an amino acid substitution. Hemoglobin S and hemoglobin C are both examples of amino acid substitutions on the beta chain.An underproduction of alpha chains occurs in alpha thalassemia. FINAL SCORE

A patient is group AB with one copy of the Se gene. What antigens will they have in their secretions? The correct answer is highlighted below A, B, & H Only B & H Only A & H Only H

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

This suspicious form measuring 15 µm was recovered from a stool specimen. Which of the following conditions is associated with this organism? The correct answer is highlighted below Balantidiasis Amebiasis Giardiasis Filariasis

Amebiasis Feedback The organism pictured is the classic trophozoite form of Entamoeba histolytica. The presence of red blood cells in the organism cytoplasm is diagnostic for this amebic organism. It may remain intestinal in nature causing amebiasis / amebic dysentery or it may migrate out of the intestinal tract and cause amebic hepatitis. The disease balantidiasis is caused by ingesting the ova of the ciliate Balantidium coli and is transmitted by the ingestion of fecally contaminated food or water. The disease giardiasis is caused by ingesting the ova of the flagellate Giardia lamblia/intestinalis and is transmitted by the ingestion of fecally contaminated food or water. Filariasis is caused by any of the microfilariae (nematodes) and is spread by blood-feeding black flies and mosquitoes. NEXT QUESTION

A sample has reactions occurring at immediate spin and AHG in a panel that show varying reaction strengths. There is no obvious pattern that matches a particular panel cell or single antigen profile and the auto-control was negative. Which of the following is the most likely cause? The correct answer is highlighted below An IgM and an IgG antibody An IgG antibody only An IgM antibody only An autoantibody

An IgM and an IgG antibody Feedback The cause would be the presence of both an IgM and an IgG antibody. Laboratorians should think of multiple antibodies when reactions are occurring at two different phases (IS and AHG), varying strengths in reactions, and no definite pattern. Patterns can sometimes be recognized if you look at each phase individually. For example reactions at immediate spin may match an M antibody, and reactions at AHG may match a D antibody. Varying strengths in reaction could also indicate dosage occurring. IgM antibodies most often react at IS, room temperature, or colder. IgG antibodies are most often detected at the AHG phase. Since the autocontrol is negative, the positive reactions are caused by an alloantibody and not an autoantibody. NEXT QUESTION

A patient demonstrates an antibody that reacts at the immediate spin phase, shows variable dosage, and has increased reactivity after treatment with enzymes. Which antibody does the patient most likely have? The correct answer is highlighted below Anti-M Anti-Fya Anti-e Anti-P2

Anti-P2 Feedback The P group antibodies are typically clinically insignificant, IgM antibodies that react best at colder temperatures. The antibodies in this group show variable dosage and their reactivity is enhanced by proteolytic enzymes. However, the rare antibodies of Anti-P and Anti-PP1Pk are clinically significant. Antibodies to M and N antigens are IgM and show dosage. However, reactivity is decreased with proteolytic enzymes. Fy, or Duffy, antibodies are IgG, clinically significant antibodies. They show dosage but are denatured by proteolytic enzymes. Rh, or Rhesus antibodies, are IgG, clinically significant antibodies. They show dosage and are enhanced by proteolytic enzymes. NEXT QUESTION

Which of the following organisms display the characteristic "Medusa head" on 5% sheep blood agar (SBA) after 18 hours of incubation at 35°C? The correct answer is highlighted below Yersinia pestis Bacillus anthracis Francisella tularensis Brucella abortus

Bacillus anthracis Feedback After 18 hours of incubation on SBA at 35°C, the slightly undulate margin of B. anthracis may show curling, displaying a so-called "Medusa head" appearance. This characteristic is also described as comma-shaped protrusions. Colonies have a ground glass appearance and are non-hemolytic, two characteristics that may also be used to differentiate B. anthracis from other Bacillus species. A distinguishing characteristic of Yersinia pestis is its preference and faster growth that occurs at 25°C. At 24 hours of incubation on SBA at 35°C, colonies are only pinpoint and translucent with a gray-white color. Colonies begin to demonstrate a "fried egg" morphology at 48 hours of incubation on SBA. F. tularensis can grow poorly or not at all on SBA, producing only tiny, pinpoint, translucent colonies at best after 18-24 hours. This organism prefers cysteine-enriched media such as chocolate (CHOC), Thayer-Martin (TM), and buffered charcoal-yeast extract (BCYE). It would be difficult to see individual colonies on SBA growth that is less than 24 hours old. Although most isolates of Brucella abortus may grow on 5% sheep blood agar and chocolate agar, enriched agars and special incubation conditions are often required to achieve optimal growth. Colonies appear small and translucent after at least 48 hours of incubation. NEXT QUESTION

Which of the following statements is correct regarding total laboratory automation (TLA)? The correct answer is highlighted below 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. Feedback 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. NEXT QUESTION

Illustrated in this photograph is a positive slide coagulase test (Image B) compared to a negative control (Image A). The clumping of the bacterial cells, as seen in Image B, results from the bacterial production of: The correct answer is highlighted below Coagulase-reacting factor Free coagulase Bound coagulase Fibrinogen

Bound coagulase Feedback The slide coagulase test is based on the detection of bound coagulase, also known as clumping factor, that is produced on the bacterial cell wall. This factor reacts directly with the fibrinogen in the plasma, resulting in the production of fibrin strands that in turn cause the cells to rapidly agglutinate. Coagulase reacting factor is a plasma substance with which the free coagulase produced by the bacterial cells reacts to form the clot seen in the tube coagulase test. FINAL SCORE

A patient was admitted to the hospital for fever, chills, weight loss, headaches, and fatigue. The patient mentioned that he had cut his hand while hunting wild boar a couple of weeks ago. Blood cultures were received in the microbiology laboratory and several days later a bone marrow specimen on the patient was received. The blood culture was positive after 5 days and the bone marrow grew a small, convex, smooth colony after 48 hours on sheep blood and chocolate agar. A gram stain was performed and demonstrated small Gram-negative coccobacilli organisms. Which of the following organisms is the cause of infection for this patient? The correct answer is highlighted below Bacillus anthracis Brucella suis Acinetobacter species Moraxella species

Brucella suis Feedback Brucella suis is the correct answer because Brucella suis is commonly found in the wild boar population. In addition, Brucella species are facultative, intracellular organisms that can live in neutrophils, monocytes, and macrophages. As a result, this organism can circulate throughout the bloodstream and invade other organs such as the spleen, liver, and bone marrow. People who have Brucella infections can be asymptomatic or symptomatic and those who are asymptomatic have a delay in medical treatment. This delay in treatment can result in relapsing brucellosis and possibly further complications of the disease. Complications that can occur are arthritis, spondylitis, and endocarditis. Bacillus anthracis is incorrect because Bacillus anthracis is commonly encountered through direct contact with sheep, goats, horses, and cattle. Bacillus anthracis infections occur through direct contact with wool or hair of infected animals, inhalation of spores, and ingestion of contaminated meat. In addition, Bacillus anthracis are large Gram-positive rods that grow within 24 hours on sheep blood and chocolate agar. Acinetobacter species is incorrect because this organism is a non-lactose fermenter and grows easily on sheep blood, chocolate, and MacConkey agar. Acinetobacter species are gram-negative coccobacilli and can often be mistaken for Neisseria species. Acinetobacter species are commonly found in the genitourinary tract, respiratory tract, and in wound infections. Moraxella species is incorrect because Moraxella species is considered normal flora of the respiratory tract. Even though it is considered part of the respiratory tract normal flora, it commonly causes respiratory, eye, ear, and sinus infections. Moraxella species are large, pink to brown colonies in color and produce a hockey puck-type colony that easily glides across the surface of chocolate media. NEXT QUESTION

Which of the following markers is associated with normal mature B cell expression? The correct answer is highlighted below CD19 CD8 CD14 C42

CD19 Feedback Normal mature B cells express CD19 (also CD20, and Kappa or Lambda). CD8 is expressed by T suppressor/cytotoxic T cells. CD14 is expressed by Monocytes. CD42 is expressed by Megakaryocytes. NEXT QUESTION

The following characteristics are applicable to Interferon-Gamma Release Assays (IGRAs) except: Can be used in patients with active tuberculosis disease symptoms Preferable for patients who have received a bacillus Calmette-Guérin (BCG) vaccination Can be used instead of purified protein derivative (PPD) Cannot differentiate latent TB from active tuberculosis infection

Can be used in patients with active tuberculosis disease symptoms Feedback Two currently approved commercially available Interferon-Gamma Release Assays (IGRAs) are approved by the Food and Drug Administration (QuantiFERON® and SPOT TB® test). Interferon-? release assays rely on the fact that T-lymphocytes will release IFN-? when exposed to specific antigens. Depending on which IGRA method is chosen either fresh whole blood or peripheral blood mononuclear cells (PBMCs) are used for testing. White blood cells from most persons that have been infected with M. tuberculosis will release interferon gamma (IFN-?) when mixed with antigens derived from M. tuberculosis. To perform an assay, fresh blood samples are mixed with antigens and controls. M. tuberculosis antigens mixture of synthetic peptides represent ESAT-6, CFP-10 and TB7.7 in QuantiFERON or ESAT-6 and CFP-10 in SPOT TB. The antigens, testing methods, and interpretation criteria for IGRAs differ. However, the IGRA method is not recommended for patients with active tuberculosis symptoms. In addition , an IGRA method should not be used in children younger than 5 years of age. Interferon-Gamma Release Assays (IGRAs) testing is preferable for patients who have received a bacillus Calmette-Guérin (BCG) vaccination (either as a vaccine or for cancer therapy). Prior BCG vaccination does not cause a false-positive IGRA test result. Interferon-Gamma Release Assays (IGRAs) can be used instead of purified protein derivative (PPD) skin test. It is recommended over tuberculosis skin testing in individuals 5 years and older and who have low or moderate risk of disease progression. Interferon-Gamma Release Assays (IGRAs)cannot differentiate latent tuberculosis from active tuberculosis infection.

Which of the following lipoproteins will form a creamy layer at the top of stored, non-fasting plasma specimens? The correct answer is highlighted below High-density lipoproteins Low-density lipoproteins Chylomicrons Very low-density lipoproteins Feedback Normally absent in fasting specimens, chylomicrons will form a creamy layer at the top of stored, non-fasting plasma specimens. Chylomicron particles are 98% lipid, 90% of which are exogenous triglycerides, which means the triglycerides originate from sources outside the body (i.e., food sources). They are the least dense of the lipoprotein particles; therefore, when a non-fasting plasma is stored, chylomicrons will rise to the top. NEXT QUESTION

Chylomicrons Feedback Normally absent in fasting specimens, chylomicrons will form a creamy layer at the top of stored, non-fasting plasma specimens. Chylomicron particles are 98% lipid, 90% of which are exogenous triglycerides, which means the triglycerides originate from sources outside the body (i.e., food sources). They are the least dense of the lipoprotein particles; therefore, when a non-fasting plasma is stored, chylomicrons will rise to the top. NEXT QUESTION

The dimorphic molds exist in both mold and yeast forms depending on the temperature of incubation. In the laboratory, when cultures are incubated at 30o C, all of the dimorphic fungi will produce mold colonies, usually within 10 - 14 days. When cultures are incubated at 35o - 37o C, yeast colonies develop usually within 3 - 5 days, with the exception of one of the dimorphic species. From the options shown below, select the genus that does not produce yeast colonies when cultures are incubated at a higher temperature. The correct answer is highlighted below Blastomyces dermatitidis Coccidioides immitis Histoplasma capsulatum Sporothrix schenckii

Coccidioides immitis Feedback Coccidioides immitis is the correct response. Coccidioides immitis is unable to convert from the mold phase to the yeast phase because the yeast form only develops within the infected tissues of the human or animal host. The yeast form can be seen as a spherule, which varies in size and contains endospores that are released into the surrounding area. Yeast colonies cannot be produced directly or from the subculture of a mold colony. Blastomyces dermatitidis is incorrect. Blastomyces dermatitidis will produce yeast colonies at 35o - 37o C. The yeast form will produce large, thick-walled cells with buds attached to a broad base. Histosplasma capsulatum is incorrect. Histoplasma capsulatum will produce yeast colonies at 35o - 37o C. The yeast form will produce a mixture of swollen hyphae and small budding yeast cells. Sporothrix schenckii is incorrect. Sporothrix schenckii will produce yeast colonies incubated at 35o - 37o C. The yeast form will produce single or multiple budding, spherical, oval, elongated, or cigar-shaped yeast cells. NEXT QUESTION

Although care should be taken when working with all fungus cultures in the laboratory, personnel are particularly prone to develop laboratory acquired infections from the inhalation of airborne species of: The correct answer is highlighted below Blastomyces dermatitidis Coccidioides immitis Sporothrix schenckii Histoplasma capsulatum

Coccidioides immitis Feedback Infection with Coccidioides immitis is acquired through the inhalation of infective arthroconidia. The delicate nature, small size and ease of aerosolization of the arthroconidia of Coccidioides immitis, separated by empty space, makes this species the most likely to result in laboratory acquired infections. Because the arthroconidia are so small and light, they more easily reach the alveolar spaces when inhaled than the conidia of other species. Particularly dangerous are older, mature cultures where spores are highly concentrated and extremely fragile. Although laboratory infections with the other fungal species listed in this exercise are possible, the spores do not become as easily aerosolized and present a less likely event. Of more probability is the direct inoculation of skin through broken glass or penetration of a needle. Blastomyces dermatitidis is believed to begin as a respiratory infection following inhalation of conidia following exposure to contaminated soil or wood. Its spores are not as readily aerosolized. Sporothrix schenckii infection is usually acquired by traumatic contact with thorns or splinters from contaminated vegetation. Histoplasma capsulatum infection occurs after inhalation of conidia from infective structures in the environment. Cases occur in those working in or cleaning out chicken coops, roosting areas of other birds, and barns, as well as in caves due to contact with bat guano.

In the in vitro coagulation scheme, factor V is primarily involved in the: The correct answer is highlighted below Extrinsic pathway ONLY Intrinsic pathway ONLY Fibrinolytic pathway Common pathway

Common pathway Feedback The common pathway, which is activated by the extrinsic and intrinsic coagulation pathways, involves factors I, II, V, and X. The role of Factor V is similar to Factor X in that both are required to convert prothrombin (Factor II) to Thrombin at the conclusion of the coagulation cascade. In vivo, thrombin can further accelerate the activation of Factor V.

The most highly specific indicator for rheumatoid arthritis is: Rheumatoid factor Cyclic citrullinated peptide antibodies (CCP antibodies) Immune complexes Complement

Cyclic citrullinated peptide antibodies (CCP antibodies) Feedback CCP antibodies are a highly specific indicator for RA. Antibodies to CCP-1 (anti-CCP-1) were first described in 1998, followed by the introduction of commercial ELISA methods using the second-generation peptides (CCP-2). Anti-CCP IgG antibodies are present in about 69% to 83% of patients with RA and have specificities ranging from 93% to 95%. Compared to other assay methods for RF, CCP is considered to be more sensitive (specificity >95%). Citrullinated tenascin-C (cTNC) is a newer glycoprotein with a 98% accuracy rate for ruling out RA. Agglutination tests for RF generally detects IgM RFs. Latex agglutination is sensitive but can produce a fairly high number of false-positive results. Because conventional procedures are semi-quantitative, they may be insensitive to changes in titer and may detect only those RFs that agglutinate. Soluble circulating immune complexes and cryoprecipitable proteins consisting of immunoglobulins, complement components, and RFs are demonstrable in the sera of some patients with RA. Complement levels are generally normal in patients with rheumatoid arthritis, except for patients with vasculitis.

Serous fluid effusions may result from all of the following EXCEPT: The correct answer is highlighted below Congestive heart failure Infection and inflammation Malnutrition Dehydration

Dehydration Feedback A serous effusion is the result of fluid build-up between the membranes where serous fluid is produced. Dehydration would not result in a serous fluid effusion. Dehydration occurs when an individual loses or uses more fluid than they take in and there is not enough water or other fluids to carry out normal functions. Congestive heart failure, infection, and inflammation, and malnutrition are all possible causes of a serous fluid effusion. NEXT QUESTION

Which of the following represent other hemoglobin gene loci that occur on the same chromosome as the beta chain loci? The correct answer is highlighted below Alpha and delta Delta and gamma Gamma and zeta Zeta and epsilon

Delta and gamma Feedback The loci for globin chain production are found on Chromosomes 11 and 16. Alpha and zeta are both found on chromosome 16. Beta, delta, epsilon, and gamma are all found on chromosome 11. Genes for the production of alpha chains are found on chromosome 16, and genes for the production of delta chains are found on chromosome 11. Genes for the production of gamma chains are found on chromosome 16, and genes for the production of zeta chains are found on chromosome 11. Genes for the production of zeta chains are found on chromosome 11, and genes for epsilon chains are found on chromosome 16. NEXT QUESTION

The glucose result on a urine specimen from an infant is negative on the urine chemical reagent strip, what is the next step? The correct answer is highlighted below It can be reported that the specimen is negative for other reducing substances such as galactose. It must be followed by the Acetest® tablet test to check for other reducing substances. There is nothing else to do, report the result as negative for glucose. It must be followed by the copper reduction test (Clinitest®) to check for other reducing substances.

It must be followed by the copper reduction test (Clinitest®) to check for other reducing substances. Feedback The method used on the urine chemical reagent strip is specific for glucose. An additional test, such as Clinitest®, should be used to check for other reducing substances. Clinitest® is a reagent tablet that is based on the classic Benedict's copper reduction reaction. This additional step is an easy way of screening for inborn metabolic problems, in particular, galactosemia. Acetest® is used as a confirmatory test for ketones and can be used to test urine, serum, and whole blood. NEXT QUESTION

Which of the following organisms is a lactose fermenter? Morganella morganni Proteus mirabilis Shigella sonnei Klebsiella oxytoca

Klebsiella oxytoca Feedback Klebsiella oxytoca produces acid/acid KIA reactions and red to pink colonies on MacConkey agar, indicating the ability to ferment lactose. Morganella morganni, Proteus mirabilis, and Shigella sonnei do not ferment lactose. They appear as Alk/Acid on KIA and as non-pigmented colonies on MacConkey agar.

In HDFN which of the following antigen-antibody reactions is occurring? The correct answer is highlighted below Maternal antibody is directed against fetal antibody. Maternal antigen is directed against fetal antibody. Maternal antibody is directed against fetal antigen. Maternal antigen is directed against fetal antigen.

Maternal antibody is directed against fetal antigen. Feedback In hemolytic disease of the fetus and newborn (HDFN), maternal antibodies are directed against fetal red blood cells. This condition can cause red cell lysis in the infant and can be dangerous for the health of the fetus - risks include RBC hemolysis, erythroblastosis fetalis, and hydrops fetalis. Antibodies are not directed against other antibodies. Antibodies are directed against antigens. Newborns do not begin antibody production until approximately 4 months of age. Antigens are not directed against other antigens. NEXT QUESTION

A patient admitted to the hospital for ongoing fever produces the following laboratory results: RBC count: 3.56 x 1012/L WBC count: 57.5 x 109/L Platelet count: 375,000/uL Differential count: 3 blasts, 10 myelocytes, 6 metamyelocytes, 12 bands, 64 segs, 4 lymphocytes, and 1 monocyte LAP score = 155. Which of the following conditions correlates closely with this patient's results? Leukemoid Reaction Chronic Myelogenous Leukemia Genetic translocation (9;22)(q34;q11) Paroxysmal Nocturnal Hemoglobinuria

Leukemoid Reaction Feedback A high white blood cell count, usually 50-100 x 109/L with a left shift, is a common finding in leukemoid reactions. In addition, a key feature of a leukemoid reaction is a high LAP score. Chronic Myelogenous Leukemia (CML) is highly associated with the Philadelphia chromosome or translocation (9;22)(q34;q11). CML typically shows a low LAP score, in contrast to the findings in this case. Finally, Paroxysmal Nocturnal Hemoglobinuria (PNH) is also associated with a low LAP score, which excludes this as the correct answer. NEXT QUESTION

How is valproic acid (Depakote) administered? The correct answer is highlighted below IM injection Sublingual Oral preparation IV

Oral preparation Feedback The correct answer is oral preparation as the gastrointestinal tract completely and rapidly absorbs valproic acid, so other delivery methods are not as useful for therapy. NEXT QUESTION

Which of the following is considered an indication for Rh immune globulin (RhIG) administration in postpartum women? The correct answer is highlighted below Long term protection Antibody blocking Passive protection Active immunity

PassivFeedback Active immunization induced by the D antigen can be prevented by the concurrent administration of the corresponding RBC antibody (anti-D). Rh-negative non-immunized mothers expecting Rh-positive infant(s) should receive Rh immune globulin (RhIG) in the third trimester or at 28 weeks' gestation. Postpartum Rh-negative non-immunized mothers should receive RhIG immediately after delivery of an Rh-positive newborn.For passive protection, RhIG therapy can be administered within 72 hours after delivery as it may be effective against formation of anti-D.There is no long term protection against the development of Rh antibodies due to potential for patient exposure in subsequent pregnancies.The mechanism for RhIG therapy does not block antibody; it attaches to the fetal Rh-positive RBCs and removed by macrophages in the maternal spleen. NEXT QUESTIONe protection

The study of how variations in the human genome affect a given individual's response to medications is called? The correct answer is highlighted below Drug half-life Therapeutic window Pharmacokinetics Pharmacogenomics (Pharmacogenetics)

Pharmacogenomics (Pharmacogenetics) Feedback Pharmacogenomics (Pharmacogenetics)- The study of how variations in the human genome affect a given individual's response to medications. Therapeutic window- The range between a drug's effective dose and its toxic dose. Drug half-life- The amount of time it takes for a drug's concentration in the body to decrease by 50%. Pharmacokinetics- The study of drug disposition in the body - how and when drugs enter the circulation, how long they stay there, and how they are eliminated. NEXT QUESTION

Which of the following cells are of lymphoid lineage? The correct answer is highlighted below Plasma cell Macrophage Eosinophil Megakaryocyte

Plasma cell Feedback A plasma cell is a lymphocyte that has responded to antigen, cloned itself, and is actively secreting antibodies. It is initially made in the bone marrow, released into the circulation as a naive lymphocyte, and then responds to its specific antigen in the lymph nodes, where it further differentiates and matures into plasma cells. Macrophages (derived from monocytes), eosinophils, and megakaryocytes develop from the myeloid stem cell, not the lymphoid stem cell. NEXT QUESTION

he majority of all laboratory errors occur during which phase of laboratory testing? The correct answer is highlighted below Preanalytic Analytic Postanalytic Errors are evenly distributed among preanalytic, analytic, and postanalytic phases of testing.

Preanalytic Feedback The correct answer is preanalytic. Studies indicate that the majority of all laboratory errors occur during the preanalytic phase of testing. Specimen handling and processing is a critical part of the testing process. Preanalytical errors can cause erroneous or misleading test results that may delay testing or give misleading results that affect the patient's care. Some examples of preanalytic errors include the wrong test ordered, using an expired tube, misidentification of a patient, delay in transportation of sample, underfilled sample tube, or using an incorrect needle size. Errors do occur in the analytic and post-analytic phases of testing, but the number of errors in these phases pale in comparison to those identified in the preanalytic phase. NEXT QUESTION

Which of the following statements is true for the reagent strip procedure? Prolonged immersion may wash out reagents. Blot the reagent strip with a paper towel before placing it on the tray of the dipstick reader. All tests require the same reading times. The expiration date on the reagent strip container does not matter, as long as the controls are acceptable.

Prolonged immersion may wash out reagents. Feedback Prolonged immersion of the strip in the specimen may wash out reagents and affect test results. Some tests on the reagent strip require specified reading times. If you are visually reading the results, it is important to adhere to the timing recommended by the reagent strip manufacturer. The edge of the strip should be run along the lip of the specimen container or touched to absorbent toweling, but should not be blotted with a paper towel. Expiration dates indicate the ensured reactivity of the reagent strips. Even though controls may be accurate, it does not guarantee that patient results will be accurate if the reagents are beyond the assigned expiration date

The test used for the identification of specific capsular serotypes of Streptococcus pneumoniae is: The correct answer is highlighted below Optochin Bile solubility Quellung Hippurate hydrolysis

Quellung Feedback The Quellung test is performed by mixing a light suspension of the suspected organism with a small amount of type-specific antiserum on a glass slide and observing for the "swollen" appearance of the capsule to detect serogroup matches of S. pneumoniae. This process both identifies and serotypes the isolate. Optochin susceptibility is used in distinguishing S. pneumoniae from other alpha-hemolytic Streptococci, but does not serve to distinguish the various serogroups. S. pnuemoniae is optochin sensitive while other alpha-hemolytic Streptococcus, such as Streptococcus viridans are resistant. Bile solubility is also used in distinguishing S. pneumoniae from other alpha-hemolytic Streptococci, but does not serve to distinguish the various serogroups. S. pneumoniae is bile solubility positive (addition of desoxycholate to a heavy suspension will lyse the cells) and Streptococcus viridans group is negative (suspension remains cloudy after addition of desoxycholate). Hippurate hydrolysis is a test useful in the differential identification of Streptococcus agalactiae (Group B Streptococcus) but has no use in the workup of pneumococci. S. agalactiae is hippurate hydrolysis positive. NEXT QUESTION

Illustrated in this photomicrograph of a gastric biopsy specimen are a few thin, curved and S-shaped bacteria (arrows). This picture is suspicious for Helicobacter pylori. An additional test helpful in confirming this identification is: The correct answer is highlighted below Indoxyl acetate Rapid urease Hippurate hydrolysis Growth at 42° C

Rapid urease Feedback Rapid urease is correct. The ability of H. pylori to rapidly hydrolyze urea not only allows it to maintain residence in the highly acid gastric mucosa (production of NH4 to neutralize the acid ions) but also provides the basis for the CLO test commonly used in GI clinics and microbiology laboratories. The CLO test is based on the rapid conversion of urea after inoculation with bits of biopsy material, in which a bright pink/red color will be produced. Indoxyl acetate, hippurate hydrolysis, and growth at 42° C are all incorrect. H. pylori reacts negatively in both the indoxyl acetate and hippurate hydrolysis tests, and most strains are incapable of growing at 42° C. H. pylori grows best at 37° C.

This Gram-positive coccus is catalase positive. The tests shown are a tube coagulase test inoculated with the isolate, and an MRSA screen plate containing 4% NaCl and 6 µg/mL of oxacillin. A 0.5 McFarland standardized inoculum of the isolate is inoculated to the plate. What step should you take next? The correct answer is highlighted below Disregard the oxacillin test because coagulase-negative staphylococci should not be tested on the oxacillin screen plate. Report the isolate as methicillin-resistant Staphylococcus aureus. Report the isolate as methicillin-susceptible Staphylococcus aureus. Test the isolate for cefoxitin susceptibility by disk diffusion testing.

Report the isolate as methicillin-resistant Staphylococcus aureus. Feedback "Report the isolate as methicillin-resistant Staphylococcus aureus" is the correct answer since the coagulase plasma is clotted indicating it is coagulase-positive and the organism is growing on the 4% NaCl and 6 µg/mL oxacillin MRSA screen plate, demonstrating resistance to oxacillin, methicillin, and nafcillin. It is true that coagulase-negative staphylococci should not be tested on MRSA screen agar but this isolate is coagulase positive. Methicillin susceptible Staphylococcus aureus would not grow on the MRSA screen plate. This test is as confirmatory as cefoxitin disk diffusion testing, so further testing is not needed and would delay treatment. NEXT QUESTION

History records an outbreak with the sudden onset of high fever, headache, and abdominal pain among 93 persons who had attended a public church dinner the week before. The photograph of an XLD agar plate is representative of the organism that may have been recovered from blood cultures from any one of these 93 persons. The most likely identification is: The correct answer is highlighted below Escherichia coli Salmonella serotype Typhi Shigella sonnei Edwardsiella tarda

Salmonella serotype Typhi Feedback The clinical history as presented is classic for typhoid fever. The HE agar plate shows the recovery of non-lactose fermenting colonies (clear appearance) some of which have black centers. This picture is consistent with Salmonella serotype Typhi, although Edwardsiella tarda is a possibility but can be ruled out because it does not cause a typhoid fever-type syndrome. Escherichia coli will appear yellow without H2S production on XLD agar and doesn't fit the clinical presentation in this case. Shigella sonnei would appear clear on XLD agar, but would not produce H2S, and doesn't fit the clinical presentation in this case. FINAL SCORE

he oocyst for this organism typically contains two mature sporocysts; however, in patient specimens the sporocysts (containing four sporozoites) that are released from the oocyst are seen singly. Which of the following organisms does this represent? Cystoisospora belli Sarcocystis species Cryptosporidium parvum Blastocystis hominis

Sarcocystis species Feedback Sarcocystis species is the correct answer because Sarcocystis species form oocysts with two mature sporocysts each containing four sporozoites. However, the oocysts of Sarcocystis species are thin-walled resulting in the release of the sporocysts. Normally, the mature oocysts will be seen with one sporocyst. Cystoisospora belli is incorrect because mature oocysts contain two sporocysts with four sporozoites; however, when compared to Sarcocystis species, the oocysts remain intact and the sporocysts are rarely seen broken out of the oocyst. Cryptosporidium parvum is incorrect because the oocyst consists of a small roundish cell wall that houses four sporozoites and as many as 5 or 6 dark granules. Blastocystis hominis is incorrect because it does not possess any of these structures; it has a central vacuole and peripheral nuclei.

he body of an adult tapeworm is known as the: The correct answer is highlighted below Proglottid Scolex Strobila Rostellum

Strobila Feedback Strobila is the correct answer because the body or strobila of a tapeworm is made up of segments known as proglottids. Proglottid is incorrect because proglottids are a chain of egg-producing units. Scolex is incorrect because the scolex is a specialized structure for attachment that is found at the anterior end of the worm. Rostellum is incorrect because this allows the organism to attach to the human intestines. The rostellum (found at the crown of the scolex) may be smooth or armed with hooks.

The viscous fluid found in the joint cavities is called: The correct answer is highlighted below Pleural fluid Peritoneal fluid Amniotic fluid. Synovial fluid

Synovial fluid Feedback Synovial fluid is the viscous fluid found in joint cavities. Pleural fluid is the fluid found in the cavity surrounding the lungs. Peritoneal fluid is fluid created in the abdominal cavity. Amniotic fluid is the protective fluid found within the membranes that hold and surround an embryo or fetus. NEXT QUESTION

A tech receives a call from the floor regarding antimicrobial therapy. The patient culture yielded an aerobic Gram-negative bacillus and the physician would like to use an antibiotic that inhibits protein translation. Which of the following antibiotics would be the best choice? The correct answer is highlighted below Vancomycin Levofloxacin Daptomycin Tetracycline

Tetracycline Feedback Tetracycline is an antibiotic that is in a group with doxycycline, minocycline, and tigecycline. Tetracyclines are effective against aerobic Gram-positive and Gram-negative species. The antibiotic inhibits protein synthesis by targeting protein translation in the 30S ribosome. Vancomycin is a glycopeptide antibiotic that is only used for Gram-positive bacteria. Additionally, this antibiotic's mode of action is inhibition of cell wall synthesis, not protein synthesis. Levofloxacin is part of the fluoroquinolones. These are effective against aerobic Gram-positive and Gram-negative species, but the target for the antibiotic is the inhibition of DNA replication in the cell. Daptomycin is a lipopeptide antibiotic that is only used for Gram-positive bacteria. Additionally, this antibiotic's mode of action is inhibition of cell wall synthesis, not protein synthesis. NEXT QUESTION

All of the following are ways hemoglobin functions EXCEPT: Transport Oxygen Transport Carbon Dioxide Transport Nitric Oxide Transport Haptoglobin

Transport Haptoglobin Feedback Hemoglobin serves to transport oxygen, carbon dioxide, and nitric oxide. Haptoglobin is a plasma protein that binds to free hemoglobin which forms a complex that can then be removed by macrophages.

In a patient with acute glomerulonephritis, you would expect to find all of the following in the urine EXCEPT: The correct answer is highlighted below Protein RBCs RBC casts Yeast

Yeast Feedback Yeast would not be an expected finding in a patient with acute glomerulonephritis. However, the presence of red blood cells, red blood cell casts, and protein is generally indicated when there is glomerular injury or hemorrhage within the kidney. NEXT QUESTION

Below are the laboratory results on a 20-year-old overweight male. His waist circumference is 41 inches and his blood pressure is 105/70. Fasting Blood Glucose: 130 mg/dL Triglycerides: 190 mg/dL HDL: 50 mg/dL The National Heart, Lung, and Blood Institute (NHLBI) and American Heart Association (AHA) have created a set of parameters to define the presence of the metabolic syndrome. Does this patient meet the criteria for metabolic syndrome diagnosis? No, because his HDL is > 40 mg/dL No, because he is not hypertensive Yes, he meets the NHLBI and AHA criteria for metabolic syndrome. No, since height and weight were not reported, his BMI cannot be calculated.

Yes, he meets the NHLBI and AHA criteria for metabolic syndrome. Feedback His measurements meet the NHLBI and AHA criteria for metabolic syndrome diagnosis. Three of the five parameters are abnormal: waist circumference, fasting blood glucose, and triglycerides. BMI is not a parameter in this set of criteria. Fasting blood glucose, triglycerides, HDL-C along with waist circumference and blood pressure are the measurements used in the NHLBI and AHA criteria. There are five basic parameters described below as metabolic risk factors. A patient must have at least three of the five risk factors to be diagnosed with metabolic syndrome. A large waistline. In women, =35 in. (88 cm); in men, =40 in. (102 cm) High triglyceride level, =150 mg/dL High fasting blood glucose, =100 mg/dL Low HDL cholesterol. In women, <50 mg/dL; in men, <40 mg/dL High blood pressure, that is, =130/85 mm Hg NEXT QUESTION