BIOLOGICAL DIAGNOSIS OF HEPATITIS-C VIRUS -INFECTIONS

Biological diagnosis of HCV infections consists of a two steps process . The first one is the detection, rarely induced by evocative symptoms , more often subsequent to systematic screenings. Third generation ELI SA tests are used for this purpose on account of their high sensitivit y. Their enhanced specificity, reaching 99.5 %, still has to be checke d using complementary tests, especially immunoblots assays. However, t hese methods may fail to detect specific antibodies during the acute p hase of HCV infections or among immunodeficient patients, resulting in discrepancies or indeterminate conclusions. Then, the detection of HC V viremia by PCR is of great value to assert the diagnosis. The second step, before treatment, consists to identify the genotype and to dete rmine the viral load by quantitation of the HCV RNA. Because the endem icity of HCV infections in France, these methods, although difficult a n expansive, should be transfered to the medical laboratories, provide d their quality and their acessibility will be preserved.