MLS Review: Clauss Fibrinogen Method to Flow Cytometry

MEDICAL LABORATORY SCIENCE 9. SUMMATIVE EXAM REVIEW QUESTIONS #12 + ANSWERS & RATIONALIZATIONS 1. 2. 3. 4. 5. 6. 7. 8. In the Clauss fibrinogen method, the time to clot formation in plasma is measured after the addition of: a. Calcium b. Thrombin c. Phospholipids d. Kaolin Which test result would be normal in a patient with dysfibrinogenemia? a. Thrombin time b. APTT c. PT d. Immunologic fibrinogen level A standard blue-top tube filled appropriately (with 4.5 mL blood) was submitted to the laboratory for preoperative PT and APTT testing. The results of both tests were elevated. The patient’s PT and APTT from the previous day were within normal limits, and he is not on heparin therapy. Which is the most appropriate first step to investigate the abnormal results? a. Report the result as obtained b. Perform a mixing study c. Check the sample for a clot d. Report the APTT only A fresh blood sample was sent to the laboratory at 8:00 a.m. for a PT test. At 4:00 p.m., the doctor requested an APTT test to be done on the same sample. What should the technologist do? a. Rerun APTT on the 8:00 a.m. sample and report the result b. Request a new sample for APTT c. Run APTT in duplicate and report the average d. Mix the patient plasma with normal plasma and run the APTT A plasma sample submitted to the lab for PT testing has been stored for 25 hours at 4°C. The PT result is shortened. What is the most probable cause? a. Factor VII deficiency b. Activation of factor VII due to exposure to cold temperature c. Lupus inhibitor d. Factor X inhibitor An abnormal APTT caused by a pathological circulating anticoagulant is: a. Corrected with factor VIII–deficient plasma b. Corrected with factor IX–deficient plasma c. Corrected with normal plasma d. Not corrected with normal plasma Which of the following abnormalities is consistent with the presence of lupus anticoagulant? a. Decreased APTT/bleeding complications b. Prolonged APTT/thrombosis c. Prolonged APTT/thrombocytosis d. Thrombocytosis/thrombosis What clotting factors (cofactors) are inhibited by protein S? a. V and X b. Va and VIIIa c. VIII and IX d. VIII and X 10. 11. 12. 13. 14. 15. 16. A thrombosis marker that has shown high sensitivity for disseminated intravascular coagulation (DIC) is: a. Thrombin-antithrombin (TAT) b. Prothrombin fragment 1.2 (PF1.2) c. Fibrinopeptide A (FPA) d. D-dimer (D-D) The APTT results are not elevated in a patient receiving heparin. Which of the following factors may be associated with the lack of response to heparin therapy in this patient? a. Protein C deficiency b. Antithrombin deficiency c. Protein S deficiency d. Factor VIII deficiency Which of the following is the appropriate principle or description of the antithrombin assay? a. In the presence of heparin, thrombin is neutralized b. Measures the time required to generate thrombin and fibrin polymers via the intrinsic pathway c. Measures inhibitors of specific factors d. An in vivo measurement of platelet adhesion and aggregation on locally injured vascular subendothelium The first step in the determination of functional antithrombin III (AT III) is to: a. Neutralize plasma antithrombin b. Neutralize thrombin with test plasma c. Incubate plasma with anti-AT III d. Precipitate AT III with plasma Which of the following is considered to be an advantage of the mechanical end-point detection methodology? a. It is not affected by lipemia in the test sample b. It has the ability to provide a graph of clot formation c. It can incorporate multiple wavelengths into a single testing sequence d. It can measure proteins that do not have fibrin formation as the end-point The fibrometer relies on the principle of: a. Clot elasticity b. Fibrin adhesion c. Conduction or impedance of an electrical current by fibrin d. Changes in optical density In the photo-optical method, the change in light transmission versus the ______ is used to determine the activity of coagulant factors or stages. a. Amount of patient’s plasma b. Amount of test reagent c. Time d. Temperature Which clinical or specimen condition will produce an increased PCV test result? a. Splenectomy b. Rouleaux formation c. Polycythemia d. Hemolytic anemia crisis 1 17. Which of the following blood specimen conditions would not cause a falsely elevated concentration with a manually performed cyanamethemoglobin determination? a. Lipemia b. Extremely elevated WBC count c. Hemoglobin S d. Hemoglobin F 18. If an MCHC result of 40 g/dL is discovered in a patient’s instrumentation printout, what is the possible cause? a. Increased RDW b. Hypochromic RBC c. Agglutinated RBCs d. Increased number of RBC fragments 19. What hematology test is useful in monitoring the production of erythrocytes? a. Total iron binding capacity b. Ferritin level c. Reticulocyte count d. Hemoglobin 20. On a Wright-stained peripheral blood smear, stress or shift reticulocytes are: a. Smaller than normal reticulocytes b. About the same size as normal reticulocytes c. Larger than normal reticulocytes d. Noticeable because of a decreased blue tint 21. Reticulocytes can be detected using ______ stain. a. New methylene blue b. Thiazole orange c. Propidium iodide d. Both A and B 22. The normal range of reticulocytes in adults is: a. 0 to 0.5% b. 0.5 to 1% c. 0.5 to 2.5% d. 1.5 to 2.5% 23. The refence value for reticulocyte count in a newborn infant is: a. Up to 13 mm per hour b. 2.5 to 6.5% c. 150 to 450 x 109/L d. 36 to 45% 24. What clinical or specimen condition will produce an increased reticulocyte count test result? a. Splenectomy b. Rouleaux formation c. Polycythemia d. Hemolytic anemia crisis 25. What clinical condition will produce a decreased reticulocyte count? a. Polycythemia vera b. Acute leukemias c. Megaloblastic anemia d. Viral infection 26. If a male patient has a reticulocyte count of 5.0% and a packed cell volume of 0.45 L/L, what is his corrected reticulocyte count? a. 2.5% b. 4.5% c. 5.0% d. 10% → Solution: = 5% x (45 / 45) = 5% 27. If a patient has a reticulocyte count of 7% and an Hct of 20%, what is the corrected reticulocyte count? a. 1.4% b. 3.1% c. 3.5% d. 14% → Solution: = 5 x (20 / 45) = 3.1% 28. If a male patient has a reticulocyte count of 6.0% and a packed cell volume of 45%, what is his RPI? a. 1.5 b. 3.0 c. 4.5 d. 6.0 → Solution: RPI = 6/1 = 6 29. Given the following values, calculate the RPI: • Observed reticulocyte count = 6% • HCT = 30% a. b. c. d. → → 2 3 4 5 Solution: CRC = [ 6 X (30/45) ] = 4 RPI = 4/2 = 2 RPI Formula: → An adequate bone marrow response usually is indicated by an RPI that is greater than 3. → An inadequate erythropoietic response is seen when the RPI is less than 2. 30. The reference value for the Westergren ESR method (adult male over 50 years) is: a. Up to 15 mm/hour b. 2.5 to 6% c. 150 to 450 x 109/L d. 36 to 45% 31. The ESR is a nonspecific indicator of disease with increased sedimentation of erythrocytes in: a. Infections b. Inflammations c. Tissue necrosis d. All of the above 32. The reference value for the Westergren ESR method for adult male less than 50 years of age is: a. 0 to 10 mm/hour b. 2.5 to 6.0% c. 150 to 450 x 109/L d. 36 to 35% 2 33. Which clinical or specimen condition will produce an increased Westergren ESR method test result? a. Splenectomy b. Rouleaux formation c. Polycythemia d. Hemolytic anemia crisis 34. Which clinical or specimen condition will produce an decreased Westergren ESR method test result? a. Polycythemia vera b. Acute leukemias c. Megaloblastic anemia d. Viral infection 35. What clinical or specimen condition will produce an increased total leukocyte count? a. Active allergies b. Immediate hypersensitivity reactions c. Inflammation d. Lipemic blood specimen 36. What clinical condition will produce an increased value of neutrophils? a. Invasive parasites → increased eosinophils b. Bacterial infections c. Viral infections → increased lymphocytes d. Tuberculosis → increased monocytes 37. What clinical condition will produce an increased value of eosinophils? a. Invasive parasites → T. spiralis cause highest eosinophil count b. Bacterial infections c. Viral infections d. Tuberculosis 38. What clinical condition will produce an increased value of lymphocytes? a. Invasive parasites b. Bacterial infections c. Viral infections d. Tuberculosis 39. A normal blood smear should have no more than approximately ___ (maximum) number of platelets per OIF in an area where the erythrocytes are just touching each other. a. 10 b. 15 c. 20 d. 25 40. If small blood clot exists in an anticoagulated blood specimen, which blood cell parameter will be affected the most? a. Leukocyte count b. Erythrocyte count c. Platelet count d. Microhematocrit 41. If platelet clumping was observed by direct observation of a stained peripheral blood smear and/or indicated by the output of an automated instrument, what corrective action can be taken? a. Retrieve the patient specimen and prepare a new blood smear b. Retrieve the patient specimen and warm it up to 37 °C for 15 minutes and reanalyze c. Recollect a new EDTA-anticoagulated specimen and promptly examine the platelets d. Recollect a new citrate anticoagulated specimen and reexamine the platelets. 42. The recommended cleaner for removing oil from objectives is: a. 70% alcohol or lens cleaner b. Xylene c. Water d. Benzene 43. Which of the following is not a benefit of laboratory instrumentation to the hematology laboratory? a. Produces faster results from specimens b. Reduced cost on rarely performed procedures c. Less variation in technique from technologist to technologist d. Increased accuracy because data are collected on more cells counted or analyzed 44. Sometimes used in conjunction with DC: a. Electronic impedance b. Optical scatter c. Radiofrequency d. None of these → Principles of automated blood cell analysis ▪ Electronic Impedance, or low-voltage direct current (DC) resistance, was developed in the 1950s and the most common methodology used. ▪ Radiofrequency (RF), or alternating current (AC) resistance, is a modification sometimes used in conjunction with DC electronic impedance. ▪ Optical Scatter, using both laser and nonlaser light, is frequently employed in today’s hematology instrumentation. 45. The abbreviation LASER stands for: a. Light associated stimulated emission of radiation b. Largely amplified by stimulated emission of radiation c. Light amplified by stimulated emission of radiation d. Liquid amplified by stimulated emission of radiation 46. Major systems in a flow cytometer include all of the following, EXCEPT: a. Fluidics b. Optics c. Computerized electronics d. Gating 47. The restriction of data analysis to one cell population is accomplished by: a. Amplification b. Gating c. Compensatory monitoring d. Data limitation 48. Which of the following can be an application of flow cytometry? a. Screening erythrocytes for malaria b. Counting reticulocytes c. Quantitation of T and B cells d. All of the above 49. The major application of flow cytometry is: a. Determining cell size and granularity b. Sorting of cells and cellular identification using monoclonal antibodies c. Treating cancer cells and identifying specific virus types d. Counting leukocytes and platelets 50. Three-part blood cell differential: a. Erythrocytes, leukocytes and platelets b. Monocytes, granulocytes, and lymphocytes c. Mononuclear cells, granulocytes, and lymphocytes d. Segmented neutrophils, eosinophils, and basophils 3