Blood coagulation hemophiliacs

A revealing assay. Suppose that you have just examined ayoung hoy with a bleeding disorder highly suggestive of classic hemophilia (factor VIII deficiency). Because of the late hour, the laboratory that carries out specialized coagulation assays is closed. However, you happen to have a sample of blood from a classic hemophiliac whom you admitted to the hospital an hour earlier. What is the simplest and most rapid test that you can perform to determine whether your present patient also is deficient in factor VIII activity ... 

Before the screening of blood and plasma and before virus inactivation procedures were applied to coagulation factor products (for example factor VIII and factor IX), many hemophiliacs who were treated with substitution therapy were exposed to infection with HIV. In the USA about 70% of tested persons with hemophiha A (factor VIII deficiency) and 35% with hemophilia B (factor IX deficiency) were HIV-seropositive (177). 

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