Improved detection of hepatitis B virus surface antigen by a new rapid automated assay

The performance of hepatitis B virus (HBV) surface antigen (HBsAg) screenin g assays is continuously improved in order to reduce the residual risk of t ransfusion-associated hepatitis B, In a multicenter study, a new automated rapid screening assay, Elecsys HBsAg (Roche Diagnostics), was compared to w ell-established tests (Auszyme Monoclonal [overnight incubation] version B and IMx HBsAg [Abbott]), Included in the evaluation were 23 seroconversion panels; sera from the acute and chronic phases of infection; dilution serie s of various HBsAg standards, HBV subtypes, and S gene mutants; and isolate d anti-HBV core antigen-positive samples. To challenge the specificity of t he new assay, sera from HBsAg-negative blood donors, pregnant women, and di alysis and hospitalized patients and potentially cross-reactive samples wer e investigated. Elecsys HBsAg showed a higher sensitivity for HBsAg subtype s ad, ay, adw2, adw4, ayw1, aym2, atw4, and adr detection in dilution serie s of different standards or sera than Auszyme Monoclonal version B and/or I Mx HBsAg. Acute hepatitis B was detected in 11 to 16 of 23 seroconversion p anels between 2 and 16 days earlier with Elecsys HBsAg than with the altern ative assays, Elecsys HBsAg and Auszyme Monoclonal version B detected HBsAg surface mutants with equal sensitivity. The sensitivity and specificity of Elecsys HBsAg were 100%, Auszyme Monoclonal version B had a 99.9% specific ity, and its sensitivity was 96.6%. IMx HBsAg showed a poorer sensitivity a nd specificity than the other assays. In conclusion, Elecsys HBsAg permits earlier detection of acute hepatitis B and different HBV subtypes than the alternative assays. By using highly sensitive HBsAg screening assays, low-l evel HBsAg carriers among isolated anti HBV core antigen-positive individua ls can be detected.