A new EIA-test to detect Hepatitis C antibody (ORTHO Diagnostic Systems) has been evaluated in four blood transfusion services in FRG (Hamburg, Hannover, Springe, Frankfurt). Among 3,123 specimens, 18 (0.58%) reacted initially positive, 13 (0.42%) remained positive after repeat testing. A detailed analysis revealed remarkable differences: blood donors from the northern part of Germany were less frequently positive than donors from the southern region (0.24% vs. 0.79%), repeat donors had a higher HCV-antibody incidence than first-time donors (0.48% vs. 0.29%). Similar differences were observed between remunerated and non-remunerated donors (0.24% vs. 0.53%), as well as between donors from rural and urban areas (0.34% vs. 0.46%). In contrast to other investigators, only a weak correlation between elevated ALT-levels (greater than 50 IU/ml) and anti-HCV seropositivity rate has been found.