Usefulness of hepatitis C virus RNA counts by second generation HCV bDNA-probe in chronic hepatitis C based on the HCV genotype

Abstract

Detection of hepatitis C virus (HCV) RNA by a second generation (ver 2) HCV bDNA-probe method (bDNA-probe) was compared with detection by the first generation (ver 1) assay. The two assays were performed simultaneously with the same serum samples of HCV genotypes 1b, 2a, 2b, 3a, and 3b. The positive rates with ver 1 were 82% for HCV genotype 1b (type 1b), 57.6% for HCV genotype 2a (type 2a), 75.0% for HCV genotype 2b (type 2b), 55.6% for HCV genotype 3a (type 3a), and 93.8% for HCV genotype 3b (type 3b). The positive rates with ver 2 were 95.0% for type 1b, 93.9% for type 2a, 83.3% for type 2b, 100% for type 3a, and 93.8% for type 3b. With Fisher's exact test, the detection rate for type 2a was significantly higher (P = 0.001) with ver 2 than with ver 1. We obtained regression lines using the HCV counts measured by bDNA-probe on the y axis and the HCV counts obtained by an HCV reverse transcriptase (RT)-competitive polymerase chain reaction method (competitive PCR) on the x axis. The gradients for types 1b, 2a, and 3b were greater with ver 2 compared to ver 1. The gradients for types 2a and 3b were the highest: for type 2a, y = 0.135x + 0.6 with ver 1 and y = 0.248x + 0.1 with ver 2; for type 3b, y = 0.366x + 0.1 with ver 1 and y = 0.727x + 0.3 for ver 2. In addition, HCV-RNA counts for all the genotypes tested in this study were significantly higher with ver 2 than with ver 1. Hence, we conclude that ver 2 of the bDNA-probe measures HCV-RNA counts closer to those obtained with competitive PCR than the ver 1 assay.

Serological and Molecular Testing in Viral Hepatitis: An Update

“…Quantitative tests have become widely available to evaluate circulating HCV RNA levels -the so called viral load (15,34,35). The bDNA test developed by Chiron depends on the capture of circulating HCV RNA by hybridization, with assessment of the quantity of RNA by chemiluminescent signal amplification (35,36). The Amplicor HCV Monitor, also developed by Roche Molecular Systems, is a PCR-based method of HCV RNA quantification, with a cutoff of 1000 copies/mL (33,(35)(36)(37)(38)(39).…”

“…The bDNA test developed by Chiron depends on the capture of circulating HCV RNA by hybridization, with assessment of the quantity of RNA by chemiluminescent signal amplification (35,36). The Amplicor HCV Monitor, also developed by Roche Molecular Systems, is a PCR-based method of HCV RNA quantification, with a cutoff of 1000 copies/mL (33,(35)(36)(37)(38)(39). At first glance, the latter system would appear to be substantially more sensitive than the bDNA test, which is reported to have a cutoff of 200,000 genome Eq/mL (30)(31)(32)(33)(34)(35).…”