Fourth generation Enzyme ImmunoAssay (ELISA) for the determination of antibodies to Hepatitis C Virus in human plasma/sera & for the screening of blood units and follow-up of HCV-infected patients. For "in vitro" diagnostic use only. Microplates are coated with HCV-specific antigens derived from “core” and “ns” regions encoding for conservative and immunodominant antigenic determinants (Core peptide, recombinant NS3, NS4 and NS5 peptides). The solid phase is first treated with the diluted sample and HCV Ab are captured, if present, by the antigens. After washing out all the other components of the sample, in the 2nd incubation bound HCV antibodies, IgG and IgM as well, are detected by the addition of polyclonal specific anti hIgG&M antibodies, labelled with peroxidase (HRP). The enzyme captured on the solid phase, acting on the substrate/chromogen mixture, generates an optical signal that is proportional to the amount of anti HCV antibodies present in the sample. A cut-off value let optical densities be interpreted into HCV antibody negative and positive results.