Detection of Antibody to Hepatitis-Associated Antigen in Hemophilia Patients and in Voluntary Blood Donors

The sera from 385 hemophilia patients and 360 normal voluntary blood donors were tested by a variety of methods for antibodies against the hepatitisassociated or hepatitis B antigen (HBAg). Anti-HB Ag was detected in 79.8% of the hemophilia sera and 7.5 % of the normal blood donor sera by a ‘sandwich’solid-phase radioimmunoassay (RIA) method. The RIA method was compared with other serologic methods (agar-gel diffusion, counterelectrophoresis, complement fixation and passive hemagglutination [PHA]) and found to be significantly more sensitive than all methods except PHA. The RIA and PHA methods were approximately equal in sensitivity as judged both by endpoint titrations and tests on the 745 sera for antibodies. The RIA method is also applicable to HB Ag detection.