The presence of antibodies to hepatitis C virus (HCV) is evidence of prior and/or ongoing exposure to HCV infection. Antibody presence, however, might not, in all cases, accurately indicate whether a blood donation contains HCV and is potentially infectious. Levels of HCV-RNA in serum and liver, in general, appear to parallel disease activity, as indicated by increased serum alanine aminotransferase (ALT) levels. In this study, the frequency and overall concordance of appearance of HCV- RNA, using PCR, and antibody, using ELISA and RIBA II, in donor sera will be undertaken.