Hepatitis C is an important complication of therapy with coagulation factor concentrates; in fact, more than 90% of post transfusion hepatitis is caused by hepatitis C. Evaluation of HCV antibodies has been carried out mainly with the ELISA method but this test generates false positive results. Therefore, we studied ninety coagulopathic patients with the aim of determining the prevalence of hepatitis C virus (HCV) antibodies using the ELISA and RIBA methods. Our study confirms that the ELISA method presents false positivities: of 60 ELISA positive patients, only 41 were confirmed by RIBA. We found a significant correlation between HCV positivity, ALT titre and the number of concentrates used annually. In conclusion, our data suggest that the RIBA test is a useful confirmatory method in ELISA HCV-positive patients. This fact is particularly important in coagulopathic patients, in whom progression of chronic hepatitis C to cirrhosis is elevated.