Analytical performance of the VERIS MDx system HCV assay for detecting and quantifying HCV RNA

Abstract

Background: The diagnosis of HCV relies on the detection of viral RNA.

Objective: To evaluate the performance of the VERIS/MDx System HCV Assay, a new automated system for quantifying HCV RNA, and to compare with the COBAS^® Ampliprep/COBAS^® Taqman™ (CAPCTM) HCV Test version 2.0.

Study design: The limit of detection was determined by Probit analysis with the 3rd International WHO HCV standard and precision by assaying in duplicate control samples with HCV RNA concentrations of 7.9; 5.0; 3.4; 1.6 and 0logIU/ml over 20 days. Analytical specificity was assessed by assaying 180 samples from negative anti-HCV and HCV RNA blood donors and linearity with replicates of serial dilutions of a clinical plasma (6.4-0.6logIU/ml). We compared the VERIS MDx HCV and CAPCTM HCV assays by testing 209 samples.

Results: The limit of detection was 6.1IU/ml [CI 95%: 5.0-8.3] and the precision, given by the standard deviation, was ≤0.11logIU/ml. Specificity was 100%. The linearity ranged from 1.5 to 6.4logIU/ml. Passing-Bablok regression analysis gave: VERIS logIU/ml=-0.33+[1.04× CAPCTM] logIU/ml, with biases for the 25th, 50th, 75th percentiles of 0.18, -0.10 and -0.06logIU/ml. The two assays were well correlated (ρ=0.92, p<0.001) and Bland-Altman analysis gave biases of 0.12, logIU/ml for genotype 1, -0.19 for genotype 2, -0.26 for genotype 3, and -0.77 for genotype 4.

Conclusion: The VERIS MDx HCV assay performed well. But, we observed an under-quantification of the genotype 4 samples.

Keywords: COBAS Ampliprep COBAS Taqman; HCV RNA quantification; Hepatitis C virus; VERIS MDx system HCV assay.