Improvement of Hepatitis C Virus (HCV) Genotype Determinationwith the New Version of the INNO-LiPA HCV Assay

Hepatitis C virus (HCV) isolates have been classified into six main genotypes. Genotyping methods, andespecially the widely used line probe assay (LiPA), are frequently based on the 5-untranslated region (5'UTR).However, this region is not appropriate for discriminating HCV strains at the subtype level and for distin-guishing many genotype 6 samples from genotype 1. We investigated the capacity of a novel LiPA (Versant HCVGenotype 2.0 assay) based on the simultaneous detection of 5'UTR and Core regions for genotypes 1 and 6 toprovide correct HCV genotypes (characterized with a phylogenetic analysis) in a set of HCV strains mainlyencountered in Western countries. The improvement was assessed by comparing the results to those obtainedwith the previous version of the assay. Of the 135 tested samples, 64.7% were concordant for genotype groupand subtype with sequencing reference results using the Versant HCV Genotype 2.0 assay versus 37.5% withthe previous version. The yield was mainly related to a better characterization of genotype 1, since the accuracy,tested in 62 genotype 1 samples, increased from 45.2% with the first version to 96.8% with the new one.However, this new version necessitates a specific PCR and could no longer be used after 5'UTR PCR used forcurrent HCV infection diagnosis. Moreover, the information provided by 5'UTR hybridization is not reliablefor correctly identifying the diversity within genotypes 2 and 4. Thus, the Versant HCV Genotype 2.0 assayremains a useful tool for clinical practice when only the discrimination between major HCV genotypes isnecessary