[Viral hepatitis: molecular diagnosis].

The structure and genetic organization of the primary hepatotropic hepatitis viruses A-E are well characterized. HAV and HEV cause acute and sometimes fulminant hepatitis without progression to chronic liver disease. By contrast, HBV, HCV and HDV infections frequently progress to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma (HCC). The specific detection of the hepatitis viruses A-E is based on serological and molecular analyses. In clinical practice, it is possible to identify the causative agent in most cases by a single serological screening test. Molecular analyses to detect HBV DNA or HCV RNA are rarely required and should be performed only in a well-defined clinical context. With the assay systems available today, the etiologic agent causing acute or chronic viral hepatitis can be specifically identified in most patients.