UNEXPLAINED HEPATITIS-C VIRUS-ANTIBODY SEROCONVERSION IN ESTABLISHED BLOOD-DONORS

Background: Understanding of the epidemiology and natural history of h epatitis C virus (HCV) infection is incomplete without reference to th e early phase of infection. The prevalence of HCV infection is well do cumented in numerous reports. The seroconversion pattern in previously antibody-negative blood donors provides a model for the study of the incidence and transmission of HCV infection. Study Design and Methods: Records of HCV antibody tests at the West Midlands Blood Transfusion Centre were reviewed to determine the seroconversion rate in 1994 amon g previously anti-HCV-negative blood donors. Seroconverting donors wer e counseled to investigate the possible routes of infection. Results: In 1994, blood donations (n = 256,935) were collected from 149,370 don ors; 24 donors (0.016%; 1/6224) were positive in the screening enzyme- linked immunosorbent assay (ELISA) and the third-generation recombinan t immunoblot assay (RIBA-3). Two donors previously negative for HCV an tibody in ELISA were positive in both tests in 1994. Four donors posit ive in ELISA and indeterminate in RIBA-3 in 1993 reacted positively in both tests in 1994. One donor negative for HCV antibody on previous s creening reacted positively in ELISA and was indeterminate in RIBA-9 i n 1994 and has become positive in both tests in 1995. A further 43 don ors negative for HCV antibody on previous screening reacted positively in ELISA and were indeterminate in RIBA-3 in 1994. Conclusion: Docume nted seroconversion can take place in the absence of exposure to recog nizable risk factors for the infection. The index donation or the dona tion immediately preceding seroconversion may be positive for HCV RNA in the polymerase chain reaction.