Performance and clinical utility of a novel fully automated quantitative HCV-core antigen assay

Abstract

Background Recently, a novel quantitative HCVcoreAg immunoassay developed for commercialisation by Abbott has become available in Europe and Asia. Objectives We evaluated the correlation of HCV-RNA and HCVcoreAg and investigated the stability of HCVcoreAg and HCV-RNA. Study design HCVcoreAg was quantified by a novel fully automated immunoassay (Architect HCVAg, Abbott, Germany). HCV-RNA quantification was performed either using the Cobas-TaqMan assay or Amplicor-HCV-Monitor (Roche-Diagnostics, Germany). Correlation of HCVcoreAg with HCV-RNA was studied cross-sectionally and longitudinally in untreated patients followed for up to 8 years. Stability of HCVcoreAg and HCV-RNA was evaluated in plasma and whole blood stored for up to 96 h at different conditions. Results HCVcoreAg showed good correlation with HCV-RNA in all 118 cross-sectional tested samples irrespective of the HCV genotype ( r = 0.75). In the majority but not all of the 10 longitudinally studied patients HCVcoreAg also demonstrated a good correlation with HCV-RNA. HCVcoreAg was stable in plasma at 4, 20, and 37 °C for up to 96 h, whereas HCV-RNA significantly declined at 37 °C. In whole blood, HCVcoreAg and HCV-RNA levels declined at all conditions with exception of HCVcoreAg at 37 °C. HCVcoreAg was stable after 1–5 freezing/thawing cycles and not light-sensitive. Conclusions HCVcoreAg represents a stable and reliable marker of viral replication showing a good correlation with HCV-RNA irrespective of the HCV genotype. HCVcoreAg determination can be used to confirm viral replication and monitor viral load or acquisition of HCV over time.