Impact of inter-genotypic recombination and probe cross-reactivity on the performance of the Abbott RealTime HCV Genotype II assay for hepatitis C genotyping

The Abbott RealTime HCV Genotype II assay (Abbott-RT-HCV assay) is a real-time PCR based genotyping method for hepatitis C virus (HCV). This study measured the impact of inter-genotypic recombination and probe cross-reactivity on the performance of the Abbott-RT-HCV assay. 517 samples were genotyped using the Abbott-RT-HCV assay over a one-year period, 34 (6.6%) were identified as HCV genotype 1 without further subtype designation raising the possibility of inaccurate genotyping. These samples were subjected to confirmatory sequencing. 27 of these 34 (79%) samples were genotype 1b while five (15%) were genotype 6. One HCV isolate was an inter-genotypic 1a/4o recombinant. This is a novel natural HCV recombinant that has never been reported. Inter-genotypic recombination and probe cross-reactivity can affect the accuracy of the Abbott-RT-HCV assay, both of which have significant implications on antiviral regimen choice. Confirmatory sequencing of ambiguous results is crucial for accurate genotyping.