Analytical and clinical performance of the Hologic Aptima HCV Quant Dx Assay for the quantification of HCV RNA in plasma samples

•Aptima HCV Quant Dx and CAPCTMv2 HCV tests were highly correlated and inclusive.•The Aptima assay appeared more analytical sensitive than the CAPCTMv2 test.•Linear responses differed with Aptima yielding higher viral loads for HCV-RNA > 4.9 Log IU/mL.•Both tests yielded interpretable results when used for monitoring antiviral treatment responses.•Both tests are useful for monitoring patients with HCV infection.

BackgroundChronic hepatitis C virus (HCV) infection can be effectively treated with directly acting antiviral (DAA) therapy. Measurement of HCV RNA is used to evaluate patient compliance and virological response during and after treatment.ObjectivesTo compare the analytical performance of the Aptima HCV Quant Dx Assay (Aptima) and the COBAS Ampliprep/COBAS TaqMan HCV Test v2.0 (CAPCTMv2) for the quantification of HCV RNA in plasma samples, and compare the clinical utility of the two tests in patients undergoing treatment with DAA therapy.Study designAnalytical performance was evaluated on two sets of plasma samples: 125 genotyped samples and 172 samples referred for quantification of HCV RNA. Furthermore, performance was evaluated using dilutions series of four samples containing HCV genotype 1a, 2b, 3a, and 4a, respectively. Clinical utility was evaluated on 118 plasma samples obtained from 13 patients undergoing treatment with DAAs.ResultsDeming regression of results from 187 plasma samples with HCV RNA > 2 Log IU/mL indicated that the Aptima assay quantified higher than the CAPCTMv2 test for HCV RNA > 4.9 Log IU/mL. The linearity of the Aptima assay was excellent across dilution series of four HCV genotypes (slope of the regression line: 1.00-1.02). The Aptima assay detected significantly more replicates below targeted 2 Log IU/mL than the CAPCTMv2 test, and yielded clearly interpretable results when used to analyze samples from patients treated with DAAs.ConclusionsThe analytical performance of the Aptima assay makes it well suited for monitoring patients with chronic HCV infection undergoing antiviral treatment.