The aim of our study was to confirm by Recombinant Immunoblot Assay (RIBA) and by neutralization assay the repeat positive reactions found by two commercially available EIAs (Ortho and Abbott) when testing samples from volunteer blood donors, patients with chronic liver disease and with hepatocellular carcinoma. Our data show a high confirmatory rate among patients with chronic viral NANBH and HCC, while among donors and patients with CLD other than NANBH the percentage of presumptive EIA positive reactions confirmed by RIBA and/or neutralization assay is much lower. In our experience, the neutralization assay appears to be somewhat more sensitive than RIBA, especially when samples show low EIA optical densities.