Immune System and Pathogen Identification, Exams of Histology

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ASCP Medical Laboratory Technician MLT

Practice Exam Questions and Answers

100% Pass

David Mungai [Date] [Course title]

ASCP Medical Laboratory Technician

MLT Practice Exam Questions and

Answers 100% Pass

If the dilution is 1:100, and the average platelet count from both sides of the hemacytometer counting chamber in 2 mm2 is 68, what is the calculated platelet count? A. 680,000/mm B. 6,800/mm C. 68,000/mm D. 680/mm E. 34,000/mm3 - Answer>> C; A simple way to calculate platelet counts on the hemacytometer is to multiply the average platelet count between the two sides of the chamber by 1,000. In this case 68 x 1,000 = 68,000 platelets. The longer derivation is as follows: The standard dilution of blood for platelet counts is 1:100; therefore the dilution factor is 100. The volume of diluted blood used is based on the area and depth of the counting area. The area counted is 1 mm2 per side (since we are using the average platelet count, we only use the area of one side) and the depth factor is 10. ((Total number of cells counted x dilution factor x depth factor(mm)) / area in mm2) = platelets per mm Which branch of the immune system has an immediate response on first exposure to a foreign antigenic stimulus? A. Cell Mediated B. Specific C. Humoral D. Innate - Answer>> D;

bind with specific membrane receptors of lymphocytes and cause release of cytotoxic substances. cause increased vascular permeability, contraction of smooth muscle, and release of histamine from basophils. bind with membrane receptors of macrophages to facilitate phagocytosis and the removal of debris and foreign substances. regulate and degrade membrane cofactor protein after activation by C3 convertase. - Answer>> B; The purpose of C3a, C4a, C5a, the split-products, of the complement cascade is to cause increased vascular permeability, contraction of smooth muscle, and release of histamine from basophils. C3a, C4a and C5a, bioactive fragments of the complement components C3, C4 and C5, respectively play a key role in mediation of immunologically provoked inflammatory responses. C4a production results from classical pathway activation while, C3a and C5a are produced by the activation of the classical pathway and/or the alternative pathway. The protein component that surrounds the genome is called a: A. Capsid B. Spike C. Co-receptor D. Syncytia - Answer>> A; The protein component that surrounds the genome is called a capsid. (True/False) A centromere that is located at the point where two chromosome arms are roughly EQUAL in length is called metacentric. - Answer>> True; Metacentric centromeres are said to be near the middle of the chromosome so that the two arms are approximately equal in length.

When the centromere is located where the two arms are not equal in length, it is submetacentric. When the centromere is located close to one end of the chromosome arm, it is acrocentric. Match the viruses below with their associated diseases.

1. Epstein-Barr
2. Varicella-Zoster
3. Rhabdovirus
4. Picornavirus A. Chicken pox B. Rabies C. Infectious mononucleosis D. Polio - Answer>> 1. C
5. A
6. B
7. D Which of the following is true of the classic Bombay phenotype? The correct answer is highlighted below Two hh genes are inherited at the H locus H substance is present A antigen is present B antigen is present - Answer>> A; In the classic Bombay phenotype, two hh genes are inherited at the H locus and there is no H antigen produced. Without H antigen, there is no way for additional sugar attachment to take place. Additional sugar attachment is necessary for the development of A and B antigens. Therefore, without H antigen, there is no development of A and B antigens.

hypertension, and cardiovascular disease in his family. He has gained a few pounds each year and his physician notes abdominal obesity. His physician orders laboratory tests to evaluate his risk of cardiovascular disease. Vital Signs and Pertinent Laboratoy Results: Blood Pressure: 128/82 mm Hg Weight: 230 lbs Height: 5' 11'' Calculated BMI: 32. Waist Circumference: 45 inches Fasting Blood Glucose: 120 mg/dL Triglycerides: 170 mg/dL HDL-C: 42 mg/dL Which one of the following statements regarding this patient is true if the physician uses the guidlines of NCEP: ATP III Diagnostic Criteria for metabolic syndrome evaluation? A. Diagnosis of metabolic syndrome; waist circumference, HDL-C, and fasting blood glucose meet the criteria B. Diagnosis of metabolic syndrome; waist circumferenc - Answer>> B; In this scenario, waist circumference, triglyceride level, and fasting blood glucose meet the criteria for diagnosis of metabolic syndrome. NCEP: ATP III criteria for diagnosis of metabolic syndrome is the presence of three or more of these components: Abdominal obesity: Increased waist circumference Men: > 40 inches Women: > 35 inches

Elevated triglycerides > 150 mg/dL or drug treatment for elevated triglycerides Reduced HDL-Cholesterol (HDL-C) Men: < 40 mg/dL Women: < 50 mg/dL Elevated blood pressure > 130/85 mm Hg or drug treatment for elevated blood pressure Elevated fasting glucose > 100 mg/dL or drug treatment for elevated glucose LDL-C is not used as a determining factor in diagnosis of metabolic syndrome with the NCEP guidelines. Which of the following terms most accurately identifies the cell indicated by the arrow in this bone marrow slide that was stained with Prussian blue iron stain? A. Siderocyte B. Sideroblast C. Ringed sideroblast - Answer>> C; The cell indicated by the arrow is a ringed sideroblast. If siderotic granules form a ring around at least half the periphery of the nucleus of a nucleated red blood cell, the cell is referred to as a ringed sideroblast. Which ethnic group has the highest incidence of hereditary hemochromatosis in the United States? A. Caucasians of Celtic descent B. African Americans C. Persons of Mediterranean descent D. Hispanics - Answer>> A; In the US, Caucasians of Celtic descent have the highest incidence of hereditary hemochromatosis. True/False

Once Fresh Frozen Plasma has been thawed at 30 - 37oC, it should be stored at what temperature? A. 1-6 ºC B. 30 - 37 ºC C. 20 - 24º C D. 45- 56º C - Answer>> A; Thawed Fresh Frozen Plasma can be stored at 1 - 6oC for 1 to 5 days. It should be relabeled as "Thawed Plasma" and used for replacement therapy only in patients requiring stable clotting factors. This member of the Enterobacteriacea gave these reactions: TSIA.................. A/A, gas (+), no H2S Ornithine............... Negative Lysine................. Positive Citrate................. Positive Urea.................. Positive Phenylalanine.......... Negative Motility................ Negative This organism is identified as: A. Enterobacter cloacae B. Klebsiella pneumoniae C. Escherichia coli D. Yersinia enterocolitica - Answer>> B; Klebsiella pneumoniae is the correct answer. Enterobacter cloacae is ornithine positive and motile. Escherichia coli is ornithine positive, citrate negative and motile. Yersinia enterocolitica is lysine negative and citrate negative.

The arrows in the images below indicate cells that may be observed in CSF samples. Identify the cell - Answer>> Presumptive malignant cells; Note the large size of the cells, the high nuclear:cytoplasm ratio, vacuolation, and nuclear irregularities. The arrows in the images below indicate cells that may be observed in CSF samples. Identify the cell - Answer>> Lymphocytes; Chromatin is dense and the cells are normal in size. The arrows in the images below indicate cells that may be observed in CSF samples. Identify the cell - Answer>> Choroidal cells; a clump of choroidal cells. These are cells that line the choroid plexus and may be shed into the CSF. They are not diagnostically significant. The arrows in the images below indicate cells that may be observed in CSF samples. Identify the cell - Answer>> Monomacrophages; The cells have abundant cytoplasm with a lacy appearance. A microliter is equal to: A. 1000 ml B. 1/1000 liter C. 100 ml D. 1/1000 ml - Answer>> D; 1/1000 ml or .001 ml The following urine test results were obtained from a 6-month-old African American infant who experiences vomiting and diarrhea after milk ingestion and has failed to gain weight:

A. using a refrigerated centrifuge B. using centrifuge tubes with tapered bottoms C. decreasing rotor speed and increasing centrifuge time D. using stoppered centrifuge tubes or a cover over the rotor chamber - Answer>> D; Using capped tubes or utilizing a centrifuge with rotor covers will greatly reduce the risk of aerosol production during centrifugation. Which cardiac biomarker is a regulator of myocyte contraction? A. Myoglobin B. cTnT C. CK-MB D. CK-MB isoforms - Answer>> B; Both cTnI and cTnT are components of the regulation of myocyte contraction. In tissues infected with Histoplasma capsulatum, which of the following is usually true? A. hyphae usually invade blood vessels B. encapsulated yeast cells are typical C. conidiophores with metulae and phialides are typical D. fungus is usually intracellular - Answer>> D; In tissues infected with Histoplasma capsulatum, the fungus is usually intracellular. Microscopic morphology of Histoplasma capsulatum can be described as large, round, single-celled macrocondidia with microconidia present on hyphae. According to the CDC, " Histoplasma capsulatum, a dimorphic fungus that causes human disease, is endemic in North and Central America, particularly in the region of the Ohio and Mississippi River valleys. Humans are infected by inhalation of the mycelial fragments and microconidia of the organism."

In performing an AHG test it is important to completely wash the red cells in order to: A. eliminate concentrations of unbound antigens B. prevent elution of cell-bound antibody C. eliminate false positive effects of Rouleaux D. avoid neutralization of the anti-human globulin serum - Answer>> D; 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 cells bound with antibody. True/False A drug that is readily cleared and has a wide therapeutic window, such as ampicillin, should always be monitored by TDM. - Answer>> False; For some drugs, such as ampicillin, the range between the minimum effective concentration and the toxic concentration is large. These drugs are thus relatively safe. Drugs that have a very narrow therapeutic window need to be monitored by TDM. Increased concentration of alpha-fetoprotein (AFP) in adults are most characteristically associated with: A. Hepatocellular carcinoma B. Alcoholic cirrhosis C. Megaloblastic anemia D. Multiple myeloma - Answer>> A; Increased alpha-fetoprotein levels in adults is usually associated with hepatocelluar carcinoma, as it is a tumor maker in this population. Alcoholic cirrhosis, megaloblastic anemia, and mutliple myeloma would not cause an increase in serum AFP.

B. Reproducibility of the assay C. Sensitivity of the assay D. Accuracy of the assay - Answer>> D; Accuracy is defined as how close an assayed value is to the actual value of an analyte. Examples of conditions resulting in benign proteinuria include: (Choose ALL correct answers) A. Multiple myeloma B. Dehydration C. Lupus erythematosus D. Orthostatic proteinuria - Answer>> B & D The presence of protein in the urine does not always indicate renal disease; benign conditions such as dehydration or orthostatic (postural) proteinuria can also produce a positive test for protein. An individual with orthostatic proteinuria will have a positive test for protein after being in an upright position for several hours, but protein will not be present in the urine if the individual has been laying down. Multiple myeloma and lupus erythematosus do not cause benign proteinuria. When iontophoresis is used to collect sweat for chloride analysis, pilocarpine is used to: A. clean the skin area B. complex with chloride C. stimulate nervous system D. induce the sweat secretion - Answer>> D; Pilocarpine actually stimulates sweat glands, which helps to induce sweat secretion during a sweat chloride test via iontophoresis.

Which one of the following is the mechanism for the production of platelet satellitism? A. An IgG antibody is directed against clotting factor VIII. B. An IgG antibody is directed against von Willebrand factor (vWF). C. An IgG antibody is directed against GP IIb/IIIA on the platelet membrane. D. An IgG antibody is directed against fibrinogen. - Answer>> C; Platelet satellitism is a rare situation in which an IgG antibody is directed against the glycoprotein IIb/IIIa complex on the platelet membrane. The antibody-coated platelets rosette around neutrophils, causing a falsely low platelet count to be recorded with automated instrumentation. Monocytes may also show some rosetting. No antibodies are formed against Factor VIII, vWF, or fibrinogen that result in platelet satellitism. Which animal was involved in the reassortment of influenza A viruses that led to the 2009 novel influenza A H1N1 virus? A. Cows B. Deer C. Horses D. Pigs - Answer>> D; Pigs are the animals that served as the virus reassortment vessel for the 2009 novel influenza A H1N1 virus. Cows, deer, and horses were not the vessels for the reassortment of the 2009 H1N1 virus. Which of the following is NOT true about real-time RT-PCR? The correct answer is highlighted below A. It is the most sensitive method for evaluating RNA

Identification of the antibody would be difficult since most of the low-frequency antigens are not present on antibody panels. This prevents the antibodies from being detected. Which of the following can reduce the contact resistance of the body and lower the amount of current needed to cause electricity- induced injury? A. Ground wires B. Wet skin C. More carbon dioxide in the air D. All the above - Answer>> B; Resistance to electrical current is dependent on the skin's thickness and moisture. Wet skin can reduce the contact resistance of the body. Contact with ground wires or increased CO2 in the air does not have an affect on the amount of current needed to cause an electricity-induced injury. Which is not an application of real-time PCR? A. Diagnosis of infectious diseases B. Measurement of gene transcription C. Drug therapy efficacy D. Amplification of DNA for northern blot - Answer>> D; The amplification of DNA for northern blot is not an application of real-time PCR. However, real-time PCR can be used to: diagnose infectious diseases, measure gene transcription, measure drug therapy efficacy, and more. In contrast to regular reverse transcriptase-PCR and analysis by agarose gels, real-time PCR gives quantitative results. An additional advantage of real-time PCR is the relative ease and convenience of use compared to some older methodologies

Which of the following refers to the most common procedure for donating whole blood for use by the general population: A. Autologous donation B. Hemapheresis C. Directed donation D. Allogenic donation - Answer>> D; Allogenic donation is also known as homologous donation. In this procedure, donor blood products are collected for transfusion and given to a random (non-directed) patient in need. A Staphylococcus aureus was recovered from a wound infection and tested for susceptibility using the CLSI guidelines for disk diffusion testing. The following results were detected: Penicillin- R Cefoxitin- R Oxacillin- S Cephalothin- S Vancomycin- S Which drug must be reported as susceptible? A. Methicillin B. Penicillin C. Vancomycin D. Cephalothin - Answer>> C; Cefoxitin is the disk to test for methicillin resistant staphylococci. Because it is resistant, cephalothin must not be reported as susceptible because it will not be therapeutic. Vancomycin intermediate and resistant Staphylococcus aureus have been reported and this is the drug of choice for treating many serious MRSA isolates. Elevation in conjugated bilirubin is most likely to be found in which of the following conditions: