Hemostasis Test 4 – Flashcards
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What is the best test to perform if a patient's partial thromboplastin time (PTT) does not rise after the typical heparin dose?
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Lp(a) mixing studies chromogenic antithrombin
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Which of the following is successfully treated with plasmapheresis?
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ITP
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Which of the following results puts the patient at an increased risk for thrombosis?
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chronically elevated fibrinogen
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What is important about the test systems used for detection of the lupus anticoagulant (LA)?
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The patient plasma and normal plasma used for mixing studies should be platelet poor
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What is the trade name for the following anti-thrombotic drug, clopidogrel, commonly used for stroke patients?
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Plavix
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A patient is suspected of having DIC. The protime and PTT are abnormal. What is the next best test to run that is supportive of this diagnosis?
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D-dimer assay
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In classical hemophilia the coagulation defect is corrected by the administration of:
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fresh frozen plasma
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Unfractionated heparin is commonly monitored by the:
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partial thromboplastin time (PTT).
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Taking which drug may be associated with increased risk of DVT?
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oral contraceptives
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A patient in the intensive care unit has anemia, schistocytes, and thrombocytopenia. The prothrombin time (PT) and partial thromboplastin time (PTT) are elevated and the fibrinogen is low. What test to confirm what diagnosis would be appropriate?
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D-dimer to confirm acute disseminated intravascular coagulation (DIC)
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There may be a prolonged bleeding time in patients taking aspirin because it interferes with:
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platelet aggregation
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An enzyme-linked immunosorbent assay (ELISA) with platelet factor 4 (PF4) coated to the surface of microplate wells is used for the diagnosis of:
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heparin-induced thrombocytopenia (HIT).
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A low platelet count in conjunction with abnormal values for the PTT, PT and the TT should lead one to suspect:
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DIC
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A fibrinogen performed on the fibrometer using the standard 1:10 dilution with Owren's buffer does not read on the standard curve. A 1:5 dilution is performed, and it is 250 mg/dL when read from the curve. what is the concentration of fibrinogen to be reported in mg/dL?
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125 mg/dL 500 mg/dL 250 mg/dL
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Which of the following coagulation tests is used to detect the presence of fibrinolysins?
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euglobulin lysis test
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What is the normal plasma concentration of fibrinogen?
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200-400 mg/dL
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Antithrombin III is enhanced by:
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heparin
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Which of the following is normal in a patient regularly taking aspirin?
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platelet count
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Bethesda Titer is used for which determination?
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Factor VIII inhibitor
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What is the primary reagent used in the PT test?
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Thromboplastin
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Which of the following coagulation tests is customarily used to monitor cumarin (coumadin) therapy?
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prothrombin time
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Which of the following is correct regarding the INR?
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it standardizes PT results
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Which of the following coagulation tests is best used to monitor heparin therapy?
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partial thromboplastin time
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Once a patient is stabilized on warfarin therapy, how often should he or she be monitored?
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once a month
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An INR of 6.5 is obtained on a patient taking warfarin. All quality control is acceptable. What should be done?
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call the healthcare provider immediately
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A patient is admitted through the hospital emergency department with thrombosis, and heparin is initially begun. Her baseline PTT, before heparin therapy, is prolonged at 68 seconds. Further laboratory studies determine that she has the lupus anticoagulant. What test should be used to monitor her heparin therapy?
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TT after first making a 1:10 dilution of the patient plasma PTT after first adding antithrombin to her plasma Chromogenic anti-Xa assay
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Which of the following is true related to the use of aspirin to prevent cardiovascular disease?
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It is used to prevent arterial thrombosis
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After confirmation of a deep vein thrombosis (DVT) and pulmonary embolus in a patient, a baseline coagulation screen and platelet count are obtained. His fibrinogen is 620 mg/dL. When the PTT is performed at 6 hours after initiation of therapy, it is 45 seconds (reference range, 25 to 37 seconds). What should be done?
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Monitor the patient with the chromogenic anti-Xa assay Report the PTT is not responding Add an additional standard amount of heparin to the patient plasma to improve the sensitivity
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Low-molecular-weight heparin (LMWH)
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is essentially as effective therapeutically as unfractionated heparin (UFH)
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All of the following are considered routine coagulation tests that are available in most large and small clinical laboratoriesexcept
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antithrombin assay
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Diagnostica Stago Instruments are based on what clot detection principle?
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chromogenic photo-optical mechanical
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Using which principle does plasma become more opaque as a clot forms and the amount of light being detected decreases?
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immunologic mechanical photo-optical
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Which of the following assays uses indirect measurement using a chromogenic substrate to quantitate heparin?
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anti-Xa assay
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Which of the following most improved safety for laboratory scientists?
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closed tube sampling
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Automatic performance of certain tests based on the results of other tests is called
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reflex testing
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What is the greatest disadvantage to photo-optical coagulation instruments?
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interference from lipemia, hemolysis, and hyperbilirubinemia
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Aspirin-induced bleeding and von Willebrand disease (VWD), type 1, are detected reliably by
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PFA 100
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Who should select the coagulation instruments for a given laboratory?
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laboratory director, clinical laboratory scientists and laboratory manager
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Examples of instrument malfunction flags include all of the following except
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hemolysis
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Why are patients treated with heparin placed on warfarin therapy shortly thereafter?
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the half-life of warfarin is such that it takes the drug 5 days to reach a steady state
