EFFECT OF GENOTYPES ON THE QUANTIFICATION OF HEPATITIS-C VIRUS (HCV) RNA IN CLINICAL-SAMPLES USING THE AMPLICOR HCV MONITOR TEST AND THE QUANTIPLEX HCV RNA 2.0-ASSAY (BDNA)

The Amplicor HCV Monitor test and the Quantiplex HCV RNA 2.0 (bDNA) as say are two commercially available assays for the quantification of he patitis C virus (HCV) RNA in clinical samples. A direct comparison of the two assays was carried out using sera frozen previously from patie nts known to be chronically infected with HCV. Overall, 61 samples fro m 51 patients were tested simultaneously by the two methods: 67% (28/4 2) of the patients were infected by HCV genotype/serotype 1, 10 % (4/4 2) with type 2, and 24% (10/42) with type 3. When the absolute value f rom each assay was examined, the Quantiplex assay gave a consistently higher reading and the mean logarithmic difference between the two ass ays was 1.4 (1.0 in type 1, 2.0 in type 2, and 2.2 in type 3). When an alyzed according to genotype, strong correlation was observed between the two assays for type 1 (r = 0.83, 95% CI 0.63-0.93, P < 0.01), but not for nontype 1 samples. Despite the difference in absolute level re ported by the two assays, there was a consistent trend of change in HC V RNA concentration by both assays in patients whose consecutive sampl es were analyzed and the differences between the two assays in consecu tive samples were within 0.4 log of each other. The results suggested that with samples containing genotype 1, the Amplicor assay was more s ensitive than the Quantiplex assay by about one log. However, the sens itivities of the two assays with nontype 1 samples were much closer pr obably due to the failure of the Amplicor assay to quantify nontype 1 genotypes effectively. (C) 1998 Wiley-Liss, Inc.