Evaluation of bleeding disorders. A detailed history and laboratory tests provide clues.

A single, optimal screening laboratory test for hemostasis would evaluate vascular, platelet, coagulation, and fibrinolytic functions. Unfortunately, such a test does not exist. The key factor in determining the presence of a bleeding diathesis is obtaining a detailed patient history. Results of coagulation tests should always be interpreted in the context of such a history. Screening tests include platelet count, PTT, and PT. Subsequent investigations depend on the results of these tests.