Collaborative study to calibrate hepatitis C virus genotypes 2-6 against the HCV International Standard, 96/790 (genotype 1)

Background and Objectives A major requirement of a hepatitis C virus (HCV) RNA nucleic acid amplification technology (NAT) assay validation is the ability of the assay to detect the six major genotypes of HCV with equivalent sensitivities. The aim of this study was to characterize and calibrate an HCV genotype panel for use in such studies. Materials and Methods Panels consisting of the first International Standard (IS) for HCV RNA NAT assays (96/790; HCV genotype 1a) and isolates of genotypes 2-6 were sent to 17 laboratories worldwide which use a variety of NAT tests, both qualitative and quantitative. The HCV RNA content of each panel member was determined and the mean titre calculated in International Units/ml (IU/ml). Results The calculated mean titres (calibrated against the HCV International Standard), in log(10) IU/ml, of the genotype 2-6 samples were 3.99, 3.81, 4.14, 4.18 and 4.61, respectively. Conclusions An HCV genotype panel, calibrated in IU/ml, has been established and should be valuable for assay validation. All the genotypes were detected by all the assays used, but it was not possible to demonstrate that the genotypes were detected with equal efficiencies.