[Hepatitis C: natural history, biology, treatment monitoring]

This article presents the laboratory tests used to diagnose hepatitis C, to evaluate the severity of the chronic fibrosing disease, and to monitor the efficacy of treatment. Histological examination of liver biopsies is of the utmost importance for evaluating the development of fibrosis. Factors that precipitate fibrosis are reviewed. The annual rate of fibrosis progression can be assessed based on the estimated duration of hepatitis C virus contamination and on the fibrosis score established using the METAVIR classification. This allows to distinguish slow, fast, and intermediate fibrosis and to estimate the mean time to cirrhosis development. Combined use of interferon alpha (3 million units three times a week) and of Ribavirine (1000-1200 mg per day orally according to body weight) for 6 to 12 months is currently the standard treatment for hepatitis C. Treatment efficacy varies with a number of virus-related factors (genotype, viral burden) and patient-related factor (hepatic fibrosis, age, sex). In nonresponders, the value of treatment should not be assessed in terms of efficacy but in terms of slowing of fibrosis progression.