Quantification of HBsAg in serum: characteristics of the assays

Abstract Introduction The presence of hepatitis B virus (HBV) surface antigen (HBsAg) in serum is the hallmark of HBV infection, and qualitative tests for its detection have been used since 1969. Recently, HBsAg quantification has been applied for monitoring chronic HBV infection during its natural history as well as for the prediction of the response to treatment. As HBsAg titres are becoming an integral part in the monitoring of chronic hepatitis B, knowledge of the characteristics of HBsAg quantitative assays is of great importance. Two automated assays are currently commercially available, namely the Architect QT (Abbott Laboratories) and the Elecsys HBsAg II Quant (Roche Diagnostics). Although the correlation between the currently approved methods for HBsAg quantification is quite good, the use of the same assay in the monitoring of individual patients with chronic HBV infection appears to be mandatory. The aim of this review is to discuss the characteristics and comparisons of available HBsAg quantitative assays. Conclusion Correlation of HBsAg quantification is good, but using the same assay in the monitoring of patients with chronic HBV infection is mandatory. Dilution steps for commercial assays minimize human error. We call for further studies to be conducted so that we are able to improve the techniques we have and further our understanding.