Detection and quantitation of HCV RNA using real-time PCR after automated sample processing

There is considerable evidence that the loss of hepatitis C virus (HCV) RNA during the first 3 months of treatment with pegylated interferon plus ribavirin is a prognostic marker of response to therapy. Real-time polymerase chain reaction (PCR) assays for quantifying HCV RNA in plasma or serum are now commercially available. The extraction of HCV RNA can also be automated. This report analyses the performance of the COBAS Ampliprep-COBAS Taqman 48 (CAP/CTM) real-time PCR assay and compares this new test with the COBAS Amplicor HCV Monitor v 2.0 assay (CAM). CAP/CTM was 100% specific. The assay was linear across a wide range of HCV RNA concentrations without sample dilution. The intra-assay variation was 0.3-3.3% and the interassay variation was 1.5-6.7%. A total of 118 clinical samples with different HCV genotypes were assayed using both methods. The results obtained using the two methods were well correlated (r = 0.89, P < 0.001). The mean difference CAP/CTM-CAM] was 0.17 log IU/ml and it was not influenced by the HCV genotype or by the subtype. It is concluded that the new CAP/CTM system is adequate for quantifying HCV RNA in clinical practice.