Improved Detection of Hepatitis B Virus Surface Antigen by a New Rapid Automated Assay

Abstract

The performance of hepatitis B virus (HBV) surface antigen (HBsAg) screening assays is continuously improved in order to reduce the residual risk of transfusion-associated hepatitis B. In a multicenter study, a new automated rapid screening assay, Elecsys HBsAg (Roche Diagnostics), was compared to well-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 series of various HBsAg standards, HBV subtypes, and S gene mutants; and isolated anti-HBV core antigen-positive samples. To challenge the specificity of the new assay, sera from HBsAg-negative blood donors, pregnant women, and dialysis and hospitalized patients and potentially cross-reactive samples were investigated. Elecsys HBsAg showed a higher sensitivity for HBsAg subtypes ad, ay, adw2, adw4, ayw1, ayw2, ayw4, and adr detection in dilution series of different standards or sera than Auszyme Monoclonal version B and/or IMx HBsAg. Acute hepatitis B was detected in 11 to 16 of 23 seroconversion panels between 2 and 16 days earlier with Elecsys HBsAg than with the alternative 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% specificity, and its sensitivity was 96.6%. IMx HBsAg showed a poorer sensitivity and 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-level HBsAg carriers among isolated anti-HBV core antigen-positive individuals can be detected.

Exceptional genetic variability of hepatitis B virus indicates that Rwanda is east of an emerging African genotype E/A1 divide

“…This suggests that in particular in the latter group a number of samples were false positive in the HBsAg ELISA. Frequent falsepositivity in HBsAg ELISA tests has been reported before in Rwanda [Pirillo et al, 2007], but also during pregnancy [Weber et al, 1999]. Nevertheless, eight HBsAg positive patients were PCR positive but had no antibodies, a constellation which may be explained by either early infection or HIV-associated immunesuppression (or a combination of both).…”

Hepatitis B virus markers in anti‐HBc only positive individuals*

“…If the s/co is`1, the sample is negative. The detection limit is 0.014 PEIU/ml and 0.017 PEIU/ml for Paul Ehrlich Institute (PEI, Langen, Germany) standards ad and ay, respectively [Weber et al, 1999].…”

A novel hepatitis B virus surface antigen immunoassay as sensitive as hepatitis B virus nucleic acid testing in detecting early infection

“…Despite the fact that many countries perform HBV DNA and HBsAg screening tests, posttransfusion HBV infection continues to occur 20‐25 . This is because a relatively long infectious window period remains before HBV DNA and HBsAg become detectable in serum 19‐22,24‐30 1,26 .…”

“…Although the sensitivity of the HBsAg assay has been improved, reduction in the window period such that it is similar to that of DNA detection remains difficult 18,19,24,25,27‐29,31 . The window period for HBV detection has been estimated to be 35 to 76 days by individual sample nucleic acid testing (NAT), 41 to 90 days by minipool NAT, and 50 to 97 days by high‐sensitivity HBsAg chemiluminescent immunoassay (CLIA) 28,30 .…”