Detection of hepatitis C virus genome in human serum by multi-targeted polymerase chain reaction.

A multi-targeted "hemi-nested" PCR (M-PCR) assay in which the primer pairs derived from the 5' non-coding (5'NC) and the nonstructural protein 3 (NS3) regions of HCV genome were concurrently used for amplification in order to compare the sensitivity and specificity of polymerase chain reaction (PCR) with different primer pairs in detecting hepatitis C virus (HCV) genome. Sera from patients with virus-associated liver diseases were examined for the presence of HCV RNA by the M-PCR method following reverse transcription to cDNA. The amplified products derived from both the 5'NC and the NS3 regions were detected in 28 (70%) of the 40 HCV RNA-positive samples. However, 12 samples (30%) were devoid of the signal of NS3-derived product. Sensitivity tests using serial dilutions of HCV RNA revealed that the 5'NC-derived band was still detectable in the 10(5)-fold diluted sample by the M-PCR method, yet the NS3-derived band could hardly be detected in the 10(4)-fold diluted sample. Thus, as previously demonstrated by a single-targeted "nested" PCR assay, the present study using the M-PCR assay has clearly shown that the 5'NC-derived primers are more sensitive and specific than the NS3-derived primers in detecting HCV RNA.