Hepatitis B virus splice variants are associated with reduced likelihood of functional cure and differ across phases of chronic hepatitis B infection

Background and aims: This study evaluated the diagnostic accuracy of the Elecsys ® HCV Duo immunoassay on the cobas e 801 analyser (Roche Diagnostics International Ltd) for the detection of hepatitis C virus (HCV) infection vs commercially available comparators.Method: This international, multicentre study was conducted at seven sites (August 2020-March 2021).Blood donor samples and clinical laboratory samples (from routine diagnostic testing, pregnant women and patients on haemodialysis) were used for specificity analyses, while confirmed HCV-positive samples and seroconversion panels were used for sensitivity analyses.All samples were pseudonymised or fully anonymised residual serum or ethylenediaminetetraacetic acid-plasma.The Elecsys HCV Duo immunoassay was compared with two registered antigen-antibody (Ag-Ab) combination assays: the Monolisa HCV Ag-Ab ULTRAV2 and Murex HCV Ag/ Ab Combination.The Elecsys HCV Duo immunoassay provides parallel, but separate, read-out of HCV Ag and Ab results (while other combination assays show a combined result only).We compared the HCV Ab (anti-HCV) module with the Elecsys Anti-HCV II and Alinity s Anti-HCV assays; no neutralisation method was available to test the HCV Ag module singularly.Results: In all blood donor samples (n = 20634), the specificity of the Elecsys HCV Duo immunoassay was 99.94% (95% confidence interval [CI], 99.89-99.97).In all clinical laboratory samples (n = 2531), the specificity of both the Elecsys HCV Duo immunoassay and the Elecsys HCV Duo anti-HCV module was 99.92% (95% CI, 99.71-99.99),vs 99.84% (95% CI, 99.59-99.96)for the Monolisa HCV Ag-Ab ULTRA V2 and 99.76% (95% CI, 99.48-99.91)for the Elecsys Anti-HCV II assays, respectively.The sensitivity of the Elecsys HCV Duo immunoassay in confirmed HCV-positive samples (n = 257) was 99.6% vs 96.1% for the Monolisa HCV Ag-Ab ULTRA V2 assay.The Murex HCV Ag/Ab Combination assay could not detect 19% of the seroconversion panels and the Elecsys Anti-HCV II assay could not detect 20%.The former found HCV infections 2 days later (58 panels; 11 undetected) and the latter 18 days later (40 panels; 8 undetected) vs the Elecsys HCV Duo immunoassay. Conclusion:The Elecsys HCV Duo immunoassay had comparable specificity and better sensitivity vs the comparator assays, including anti-HCV tests.The Elecsys HCV Duo immunoassay may be an alternative diagnostic tool in countries where nucleic acid testing is not possible.