Experience in the laboratory detection of the carrier state of classic hemophilia.

The predictive odds for suspected carriers of hemophilia have been calculated using data derived from normal and known carrier populations. For each individual, the concentration of Factor VIII-related antigen and Factor VIII biological (procoagulant) activity was measured and the data were studied by linear discriminant analysis. Forty-five suspected carriers were evaluated, with 31 percent (14/45) classified as carriers. Using Factor VIII procoagulant activity alone, 18 percent (8/45) appeared as carriers, while the ratio method of activity level to antigen level showed 44 percent (20/45).