Medical Emergencies · single question
When a patient with hemophilia requires a dental procedure, which laboratory test is MOST important to check?
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Correct answer: B. PTT (partial thromboplastin time)
- A. PT measures the extrinsic pathway (factors VII, X, V, II, fibrinogen) — normal in hemophilia.
- B. Correct. Hemophilia A (Factor VIII deficiency) and Hemophilia B (Factor IX deficiency) are intrinsic pathway defects. The PTT (partial thromboplastin time) measures the intrinsic and common pathways and will be PROLONGED in hemophilia. PT/INR are typically NORMAL.
- C. INR is derived from PT — normal in hemophilia; used for monitoring warfarin therapy.
- D. Platelet count is normal in hemophilia — platelets are not affected; it is the clotting factor that is deficient.
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