HEPATITIS-C VIRUS SEROCONVERSION RATE IN ESTABLISHED BLOOD-DONORS

The results of hepatitis C virus (HCV) antibody test of 237,813 blood donations collected from 143,815 donors by the West Midlands Blood Tra nsfusion Centre in 1993 were analyzed retrospectively in order to dete rmine the seroconversion rate among established previously anti-HCV ne gative donors. Three hundred sixteen (0.22%; 1 in 455) donors were pos itive by the enzyme linked immunosorbent assay (ELISA) screening test and 34 (0.024%; 1 in 4,230) donors were positive by ELISA and the Reco mbinant Immune Blot Assay (RIBA). Three donors previously negative for HCV antibody reacted positively by both tests. The annual seroconvers ion rate was calculated as one in 35,937 donors. This figure argues ag ainst limitation of HCV antibody screening to new blood donors. A furt her 45 donors negative on previous screening reacted positively by ELI SA and were indeterminate by RIBA. Unexpectedly, lapsed blood donors f irst tested for HCV antibody in 1993 had high positive reaction rates by ELISA and RIBA, which was significantly (P < 0.001) higher than tho se of new donors. RIBA-positive reaction rate among ELISA-positive don ors was significantly higher amongst males than females (P < 0.001). ( C) 1995 Wiley-Liss, Inc.