Clinical performance of the VERIS HCV assay for hepatitis C virus RNA quantification.

BACKGROUND: Diagnosis of hepatitis C virus (HCV) infection and treatment monitoring rely on detection/quantification of HCV RNA and real-time polymerase chain reaction (PCR) techniques are expected to equivalently quantify the different HCV genotypes.

OBJECTIVE: The clinical performance of the VERIS HCV assay for HCV RNA quantification was compared to that of the Abbott RealTime HCV assay.

STUDY DESIGN: Qualitative concordance and quantitative comparison were evaluated on a first panel of 286 clinical samples containing HCV genotypes 1-6. Forty additional genotype 4 samples were tested to explore genotype 4 HCV RNA underquantification.

RESULTS: Qualitative discrepancies were observed for low viral loads (<2 log10 IU/mL) in patients under antiviral therapy and would not have had any impact on patients' management with the current guidelines for the monitoring of patients on direct-acting antivirals (DAAs). Quantification results were well correlated (R2 =0.89) with an overall minimal quantification bias (mean VERIS - Abbott difference) of -0.09 log10 IU/mL. Quantification agreement for genotypes 1, 2 and 3 samples was excellent, but reached -0.57 log10 IU/mL for 46 genotype 4 samples. A lower quantification bias of -0.24 log10 IU/mL was observed when testing 40 additional genotype 4 samples with a second reagent lot. Underquantification was not associated with 5' untranslated region (UTR) sequence polymorphisms but could be explained by 5' UTR RNA molecular modeling.

CONCLUSION: HCV RNA quantification by the VERIS HCV assay and the Abbott RealTime HCV assay was well correlated for all HCV genotypes, except genotype 4 where 5' UTR RNA folding may impact quantification. Nevertheless, this underestimation of HCV RNA levels had no impact on clinical use.