Comparative analysis of quantification of viral load in patients infected with hepatitis C virus: Quantiplex HCV RNA assay and Amplicor Monitor assay

OBJECTIVE: two standardized techniques, Quantiplex HCV RNA 2.0 (bDNA) and A mplicor Monitor, were evaluated for the quantification of hepatitis C virus (HCV) load. Our objectives were: 1) to determine the relationship between viral load and genotype, and 2) to evaluate viral load in serial serum samp les and in patients with normal or slightly elevated liver enzyme values in an area with a high prevalence of genotype 1. RESULTS: the viral loads detected with the two methods correlated significa ntly (r = 0.7, p < 0.0001), but viral load was smaller with the Monitor tha n with the Quantiplex assay, and was independent of genotype. The Monitor/Q uantiplex ratio was lower in patients with a non-1 genotype than in patient s with genotype 1b. Virological characteristics were similar in patients wi th normal or slightly elevated enzyme levels and in patients with elevated enzyme values. Neither method showed a relationship between viral load and age, sex, duration of the infection, mode of transmission, or histological activity index. CONCLUSION: viral load was not dependent on genotype. Measurement of viral load in a single serum sample adequately reflected the viral load measured in several serum samples from patients with chronic HCV infection. Patients with normal liver enzyme levels are not good candidates, in virological te rms, for treatment with interferon.