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MLPAO Hematology and Coagulation Fundamentals Flashcards

6 cards from real MLPAO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. What is the normal adult platelet count reference range?

    Answer: 150-400 × 10⁹/L

    The normal platelet count range is approximately 150-400 × 10⁹/L. Counts below 150 × 10⁹/L constitute thrombocytopenia, while counts above 400 × 10⁹/L constitute thrombocytosis. Spontaneous bleeding typically does not occur until counts fall below 20-30 × 10⁹/L.

  2. Which coagulation test measures the extrinsic and common pathways?

    Answer: Prothrombin time (PT)

    The prothrombin time (PT) measures the extrinsic (Factor VII) and common (Factors X, V, II, and fibrinogen) coagulation pathways. It is triggered by adding tissue thromboplastin (tissue factor) and calcium to citrated plasma. PT/INR is used to monitor warfarin therapy.

  3. What is the INR and why was it developed?

    Answer: International Normalized Ratio; to standardize PT results across laboratories using different thromboplastin reagents

    The INR (International Normalized Ratio) was developed to standardize PT results across laboratories using thromboplastin reagents with different sensitivities. The INR = (patient PT/mean normal PT)^ISI, where ISI is the International Sensitivity Index of the thromboplastin reagent.

  4. Which coagulation factor is deficient in hemophilia A?

    Answer: Factor VIII

    Hemophilia A is caused by deficiency of Factor VIII, an essential cofactor in the intrinsic pathway. It is an X-linked recessive disorder primarily affecting males. Severity depends on residual Factor VIII activity: severe (<1%), moderate (1-5%), or mild (5-40%).

  5. What anticoagulant is required for coagulation testing and why?

    Answer: Sodium citrate 3.2%; it reversibly chelates calcium

    Sodium citrate (3.2%, blue-top tube) is required for coagulation testing because it reversibly chelates calcium, preventing coagulation while preserving coagulation factor activity. When calcium is added back in the test procedure, the coagulation cascade can proceed normally.

  6. What does the D-dimer test measure and what is its primary clinical application?

    Answer: Fibrin degradation products from cross-linked fibrin; ruling out venous thromboembolism

    D-dimer measures degradation products from cross-linked fibrin, indicating that both thrombin generation (clot formation) and plasmin activity (clot breakdown) have occurred. Its primary clinical use is ruling out deep vein thrombosis and pulmonary embolism due to its high negative predictive value.