Medical Emergencies · patient case question
Patient B has hemophilia A. Which laboratory test is the relevant screening value?
Patient case: Bleeding Risk Assessment
demo: 3 patients presenting for extractions on the same morning
chief: Pre-operative hemostasis assessment
history: Patient A: coronary stent, taking aspirin and clopidogrel. Patient B: hemophilia A. Patient C: family history of easy bruising and prolonged bleeding after minor cuts.
meds: See individual histories
findings: All three require routine simple extractions.
Show answer and explanation
Correct answer: B. Partial thromboplastin time (PTT)
- A. Platelet count is normal in hemophilia; the defect is in the coagulation cascade, not platelet number.
- B. Correct. Hemophilia A is factor VIII deficiency, an intrinsic pathway defect, so the PTT is prolonged.
- C. PT assesses the extrinsic pathway (factor VII) and is used to monitor warfarin; it is normal in hemophilia A.
- D. Bleeding time reflects platelet function and vessel integrity, both normal in hemophilia A.
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