New perspectives in the diagnosis of hepatitis C.

Since the identification and molecular characterization of the non-A, non-B hepatitis virus (HCV) in 1989, a variety of diagnostic tests based on the detection of hepatitis virus antibodies or HCV RNA in the serum have been developed and refined. The enzyme-linked immunosorbent assays (ELISAs) and the recombinant immunoblot assays (RIBAs) exhibit improved sensitivity and specificity for HCV antibodies compared with their predecessors, and the ELISA-3 is at the forefront of HCV screening. Furthermore, the advent of molecular assays that employ quantitative reverse-transcriptase polymerase chain reaction to detect HCV RNA has allowed clinicians to track the natural history of HCV and to monitor the progress of therapy. A role for further refinement of an HCV diagnosis using tests to determine genotype, subtype, and quasispecies is explored. In addition, the role of liver biopsy and non-invasive markers of histologic status are placed into the context of patient prognosis. This article reviews the state-of-the-art tests and assays developed for the diagnosis and management of HCV infection.