Assessment of viral loads in patients with chronic hepatitis C with AMPLICOR HCV MONITOR version 1.0, COBAS HCV MONITOR version 2.0, and QUANTIPLEX HCV RNA version 2.0 assays

The correlation between response to antiviral therapy and pretreatment vira l load in patients with chronic hepatitis C has prompted the development of quantitative assays to measure viral load. The aim of our study was to ass ess the clinical relevance of the newly developed semiautomated PCR system COBAS HCV MONITOR version 2.0 in comparison with (i) the AMPLICOR HCV MONIT OR version 1.0 assay, which underestimates RNA concentration of hepatitis C virus (HCV) genotypes 2 to 6, and (ii) the QUANTIPLEX HCV RNA version 2.0 assay, which achieves equivalent quantification for each HCV genotype, with samples from 174 patients diagnosed with chronic hepatitis C before therap y. The level and range of quantification measured with AMPLICOR HCV MONITOR version 1.0 were 1 log lower than when measured with the COBAS HCV MONITOR version 2.0, at 0.261 x 10(6) RNA copies/ml (range, 0.001 x 10(6) to 2.50 x 10(6) RNA copies/ml) and 4.032 x 10(6) RNA copies/ml (range, 0.026 x 10(6 ) to 72.6 x 10(6) RNA copies/ml), respectively. The two assays showed a poo r correlation (r(2) = 0.175). The level and range of quantification were si milar when measured with the COBAS HCV MONITOR version 2.0 and QUANTIPLEX H CV RNA version 2.0 assays, at 3.03 x 10(6) RNA copies/ml (range, 0.023 x 10 (6) to 72.6 x 10(6) RNA copies/ml) and 4.91 Meq/ml (range, 0.200 to 39.5 Me q/ml), respectively. The two assays showed a strong correlation (r(2) = 0.6 86) for each HCV genotype. The duration of treatment (6 or 12 months) is mo dulated according to HCV genotype and viral load. Our results indicate that COBAS HCV MONITOR version 2.0 and QUANTIPLEX HCV RNA version 2.0 assays sh owing an equal dynamic range for each HCV genotype are suitable tools to as sess patients before therapy.