[Interpretation of hepatitis C virus serology: immunoblot and genome amplification].

In France, screening for anti-hepatitis C virus (HCV) among blood donors has been performed since 1 March 1990. It is usually carried out using enzyme immunoassays (EIA). Positive or dubious results may be linked to false positive EIA reactions. Therefore the use of an immunoblot assay such as RIBA can be very useful to assess false positive signals. Moreover, the analysis of the different antibody reactivities makes it possible to evoke a viremic status or not. The follow-up provides essential information on recent seroconversion. However, some profiles do not allow a conclusion to be drawn between chronicity and serological sequel. In these cases, polymerase chain reaction (PCR) has to be implemented in order to conclude between the two.