A comparison of "carrier screening" of hemophilia by the ratio of factor VIII coagulant activity or antigen to factor VIII related antigen.
The ratio of factor VIII coagulant activity (VIIIC) or antigen (VIIICAg) to that of factor VIII related antigen (VIIIRAg) was measured in 15 normals, 21 obligatory and 23 possible carriers of hemophilia. Factor VIII coagulant was measured on fresh plasma samples whereas antigenic properties were measured on frozen and thawed samples. In obligatory carriers only, the mean level of VIIICAg was significantly lower than VIIIC and there was a tendency for low VIIICAg levels to be associated with raised VIIIRAg levels. Using both ratios, 13 obligatory carriers were outside the normal tolerance ellipse. In possible carriers, neither ratio showed superior discriminating power. In reference laboratories that perform carrier studies on stored or transported specimens, measurement of VIIICAg/VIIIRAg is a suitable test for diagnosis of carriers.
D000941:Antigens / Q000032:analysis*; D002353:Carrier State / Q000175:diagnosis*; D005169:Factor VIII / Q000032:analysis / Q000276:immunology*; D005260:Female; D006467:Hemophilia A / Q000235:genetics / Q000276:immunology*; D006801:Humans; D014841:von Willebrand Factor
D000941:Antigens; D014841:von Willebrand Factor; D005169:Factor VIII