Improved detection of hepatitis B surface antigen (HBsAg) in blood donors by monoclonal radioimmunoassay

Abstract
The performance of a monoclonal radioimmunoassay (M-RIA) with enhanced sensitivity and high specificity for hepatitis B surface antigen (HBsAg) was evaluated in blood donors. The results were compared to a conventional RIA that used polyvalent antibodies (P-RIA). Analysis of 6409 American blood donors not reactive by P-RIA revealed an additional 1.4 HBsAg-positive donors per 1000 by M-RIA, or an approximate 60%, improvement in HBsAg detection rate. In 995 Israeli blood donors negative by P-RIA, 11 additional HbsAG-positive donors were identified. The 55% improvement in detection rate was similar to that observed with American blood donors. Since several of the newly identified HBsAG-positive blood donors had antibodies to the core antigen (anti-HBc) as the only serologic evidence of recent or past hepatitis B exposure, an additional 68 anti-HBc-positive individuals were studied with the M-RIA. Twenty-six percent (18/68) reacted only by M-RIA and not by P-RIA. Apparently, there are blood donors with HbsAG undetectable by P-RIA.