Comparison of Conventional PCR with Real-Time PCR and Branched DNA-Based Assays for Hepatitis C Virus RNA Quantification and Clinical Significance for Genotypes 1 to 5

Abstract

ABSTRACT The key parameter for diagnosis and management of hepatitis C virus (HCV) infection is HCV RNA. Standardization of HCV RNA assays to IU is mainly based on genotype 1 panels. Little is known about the variability of commercially available HCV RNA assays for quantification of different genotypes. Two real-time reverse transcription (RT)-PCR assays (COBAS TaqMan HCV Test for use with the High-Pure System [HPS/CTM] and COBAS Ampliprep/COBAS TaqMan HCV Test [CAP/CTM]), one standard RT-PCR assay (COBAS Amplicor HCV Monitor 2.0 [CAM]), and one signal amplification assay (Versant Quantitative 3.0 [branched DNA {bDNA}]) were compared for quantification of genotypes 1 to 5 ( n = 108). Using CAM as a reference assay for genotype 1-infected patients, the mean interassay differences compared with CAP/CTM, HPS/CTM, and bDNA were 0.16, −0.13, and −0.48 log 10 IU/ml HCV RNA, respectively. Comparison of CAM with CAP/CTM, HPS/CTM, and bDNA for the remaining genotypes showed the following results, respectively: 2a/c, −0.24, −0.78, and −0.49; 2b, −0.21, −0.18, and −0.64; 3a, 0.13, −1.04, and −0.55; 4, −0.52, −1.51, and −0.05; and 5, −0.28, −1.00, and −0.24 log IU/ml HCV RNA. A correct decision for treatment discontinuation in genotype 1 patients at week 12 was possible only when the same assay was used at baseline and week 12. Comparison of CAM with the CAP/CTM assay showed equal quantifications of genotype 1, 2, 3, and 5 samples, while genotype 4 samples were slightly underestimated. For the HPS/CTM assay, a significant underestimation of the HCV RNA concentrations of genotypes 2a/c, 3, 4, and 5 was observed. For the bDNA assay, a constant lower quantification of genotypes 1 to 3 was detected.