ASCP Hematology part 3 Exam Q & A

The APTT: A. tests the extrinsic coagulation pathway B. monitors Coumadin therapy C. requires tissue thromboplastin D. monitors heparin therapy - ANSWER-D. monitors heparin therapy Aliquots of plasma with a prolonged PT and prolonged APTT are mixed using various ratios of patient plasma and normal plasma. All samples are incubated at 37*C and tested at 10-, 30-, and 60-minute intervals. The PT and APTT results on all of the mixtures are corrected. These results would indicate the presence of: A. circulating anticoagulant B. factor deficiency C. contaminated reagent D. antibodies - ANSWER-B. factor deficiency A patient is taking 10mg per day of Coumadin. The results of which of the following laboratory tests will be most impacted? A. protein C level B. antithrombin III level C. Factor V Leiden mutation D. Factor VIII level - ANSWER-A. protein C level A prolonged thrombin time and a normal reptilase-R time are characteristic of: A. dysfibrinogenemia B. increased D-dimer C. fibrin monomer-split product complexes D. therapeutic heparinization - ANSWER-D. therapeutic heparinization The best test to determine if a sample is contaminated with heparin is: A. fibrinogen B. thrombin time C. prothrombin time D. stypven time - ANSWER-B. thrombin time In a Clauss fibrinogen method, the time to clot formation in plasma is measured after the addition of: A. calcium B. thrombin C. phospholipids D. kaolin - ANSWER-B. thrombin If a patient with a prolonged APTT that does not correct upon mixing, the next performed should be: A. Factor II B. DRVVT C. Factor VIII D. platelet count - ANSWER-B. DRVVT Excess D-dimer indicate that clots have been: A. converted into fibrinogen monomers B. released into circulation C. formed and are being excessively lysed D. stimulated to activate platelets - ANSWER-C. formed and are being excessively lysed D-dimers are produced from: A. cross-linked and stabilized fibrin clot B. decreased fibrinogen and platelets C. plasminogen converting to plasmin D. generation of thrombin from endothelial cells - ANSWER-A. cross-linked and stabilized fibrin clot A bedside test that can be used to monitor heparin activity is the: A. activated clotting time B. stypven time C. reptilase time D. partial thromboplastin time - ANSWER-A. activated clotting time Which of the folowing laboratory findings is associated with Factor XIII deficiency? A. prolonged activated partial thromboplastin time B. clot solubility in a 5 molar urea solution C. prolonged thrombin time D. prolonged prothrombin time - ANSWER-B. clot solubility in a 5 molar urea solution Heparin acts by: A. precipitating fibrinogen B. binding calcium C. activating plasmin D. inhibiting thrombin - ANSWER-D. inhibiting thrombin Low molecular weight heparin is monitored by a: A. anti-Xa assay B. APTT C. PT D. anti-IIa assay - ANSWER-A. anti-Xa assay In an automated cell counter, the WBC printed result is "+++". The next step is to: A. repeat after warming the sample to 37*C B. make an appropriate dilution of the sample C. recalibrate the machine from pooled samples D. request a new sample immediately - ANSWER-B. make an appropriate dilution of the sample A specimen run on an automatic cell counter has a platelet count of 19 x 10^3/uL (19 x 10^9/L). The first thing the technician should do is: A. report the count after the batch run is completed B. request a new specimen C. review the stained blood smear D. notify the laboratory manager - ANSWER-C. review the stained blood smear The electrical resistance method of cell counting requires: A. equal-sized particles B. a conductive liquid C. 2 internal electrodes for current D. three apertures for counting - ANSWER-B. a conductive liquid On an electronic particle counter, if the RBC is erroneously increased, how will other parameters be affected? A. increased MCHC B. increased hemoglobin C. decreased MCH D. increased MCV - ANSWER-C. decreased MCH On setting up the electronic particle counter in the morning, one of the controls is slightly below the range for MCV. Which of the following is indicated? A. call for service B. adjust the MCV up slightly C. shut down the instrument D. repeat the control - ANSWER-D. repeat the control Which of the following will not cause erroneous results when using a phase optical system for enumerating platelets? A. incipient clotting B. decreased hematocrit C. Howell-Jolly bodies D. leukocyte cytoplasmic fragments - ANSWER-B. decreased hematocrit The most common cause of error when using an automated cell counter is: A. contamination of the diluent B. inadequate mixing of the sample prior to testing C. variation in voltage of the current supply D. a calibrating error - ANSWER-B. inadequate mixing of the sample prior to testing The photo-optical method of endpoint detection is described as: A. change in optical density as a result of a fibrin clot B. measurement of turbidity of antigen-antibody formation C. decreased motion of a mechanical ball D. color-producing chromophor - ANSWER-A. change in optical density as a result of a fibrin clot The ideal capillary blood collection site on a newborn is: A. tip of the thumb B. ear lobe C. plantar surface of the heel D. the great toe - ANSWER-C. plantar surface of the heel When evaluating a smear for a reticulocyte count, the technician observes that the red blood cells are overlapping throughout the entire slide. The most likely explanation is: A. grease on the slide prevented even spreading B. improper proportions of blood and stain were used C. the slide was dried too quickly D. the drop used for the slide preparation was too large - ANSWER-D. the drop used for the slide preparation was too large If a blood smear is dried too slowly, the red blood cells are often: A. clumped B. crenated C. lysed D. destroyed - ANSWER-B. crenated A citrated blood specimen for coagulation studies is to be collected from a polycythemic patient. The anticoagulant should be: A. the standard volume B. reduced in volume C. changed to EDTA D. changed to oxalate - ANSWER-B. reduced in volume Blood collected in EDTA undergoes which of the following changes if kept at room temperature for 6-24 hours? A. increased hematocrit and MCV B. increased ESR and MCV C. increased MCHC and MCV D. decreased reticulocyte count and hematocrit - ANSWER-A. increased hematocrit and MCV The specimen of choice for preparation of blood films for manual differential leukocyte counts is whole blood collected in: A. EDTA B. oxalate C. citrate D. heparin - ANSWER-A. EDTA A platelet determination was performed on an automated instrument and a very low value was obtained. The platelets appeared adequate when estimated from stained blood film. The best explanation for this discrepancy is: A. many platelets were abnormally large B. blood sample is hemolyzed C. white cell fragments are present in the blood D. red cell fragments are present in blood - ANSWER-A. many platelets were abnormally large When platelet concentrate at the edge and feathered end of a blood smear, it is usually due to: A. abnormal proteins B. inadequate mixing of blood and anticoagulant C. hemorrhage D. poorly made wedge smear - ANSWER-D. poorly made wedge smear On a smear made directly from a finger stick, no platelets were found in the counting area. The first thing to do is: A. examine the slide for clumping B. obtain another smear C. perform a total platelet count D. request another finger stick - ANSWER-A. examine the slide for clumping The anticoagulant of choice for routine coagulation procedures is: A. sodium oxalate B. sodium citrate C. heparin D. sodium fluoride - ANSWER-B. sodium citrate A blue top tube is drawn for coagulation studies, the sample is a short draw, results may be: A. falsely shortened B. correct C. unable to be obtained D. falsely prolonged - ANSW