Comparison of the sensitivity of nested PCR in the 5' non-coding and the NS5 regions of the HCV genome.
Thirty-seven patients with antibodies to hepatitis C virus detected by second-generation enzyme-linked immunoabsorbent assay were studied. Serum of 20 patients with increased serum alanine aminotransferase and 17 patients with normal serum alanine aminotransferase levels was tested for hepatitis C virus RNA with reverse transcription and nested polymerase chain reaction. The nested polymerase chain reaction was independently performed in both the 5' non-coding region and putative non-structural 5 region. The results of these 37 sera were: 28 5' non-coding region polymerase chain reaction positive (17 with increased alanine aminotransferase) and 13 non-structural 5 region polymerase chain reaction positive (8 with increased alanine aminotransferase). Eighteen of the 20 patient with increased alanine aminotransferase (90%) and 11 of the 17 patients with normal alanine aminotransferase (65%) were polymerase chain reaction positive. Of the 28 5' non-coding region polymerase chain reaction positive subjects, 16 were non-structural 5 region polymerase chain reaction negative. The failure to amplify hepatitis C virus-RNA using the non-structural 5 region primers in these patients may be related to the higher genetic variability in the non-structural 5 region than in the 5' non-coding region. Overall, the 5' non-coding region polymerase chain reaction provides a more reliable test for the diagnosis of hepatitis C virus. However, a recombinant immunoblot assay-2 indeterminate patient with increased alanine aminotransferase was polymerase chain reaction negative in the 5' non-coding region and polymerase chain reaction positive in the non-structural 5 region. For this patient, the specificity of the non-structural 5 amplified product was confirmed by hybridization and sequencing.