Performance Evaluation of Immunoassay Detection of HBsAg Mutants and Their Clinical Significance in the High Risk Groups

ABSTRACT

BACKGROUND: False negative results have been reported in the immunodetection of hepatitis B virus (HBV) because of the existence of the various mutants of the virus, causing most suppliers to try to develop superior reagents by using highly sensitive and specific monoclonal or polyclonal antibodies. In this study, we evaluated the effectiveness of 3 newly developed reagents by major manufacturers by adopting automated methods with increased sensitivity and specificity in the detection and discrimination of native and recombinant mutant antigens. METHODS: We analyzed samples confirmed positive for hepatitis B surface antigen (HBsAg), high-risk samples from chronic hepatitis patients treated with antiviral agents, and samples from patients who had undergone liver transplantation and were treated with high-dose hepatitis B immunoglobulin (HBIG) by using reagents and systems newly developed by Abbott Laboratories (USA), Roche Diagnostics (Germany), and Siemens Healthcare Diagnostics (USA). Recombinant sample panels from these manufacturers with low and high concentrations were also analyzed for comparing the 3 reagents. RESULTS: There were no discrepant results among the various selected patient groups; however, for the recombinant mutant panels, all of the 3 reagents showed highly positive detection rates for their corresponding mutant panels, but showed relatively discrepant mutant detection rates when cross-tested with the other mutant panels. Detection rates of the HBsAg mutant panels were higher at a higher concentration of the mutant samples, but were lower for the same mutant receptor sites at a lower concentration. CONCLUSIONS: The 3 major detection methods seem to recognize the major native mutants commonly encountered in clinical practice. However, in the case of recombinant mutants, we believe that our data are not to be interpreted as a reference standard for any reagent, because the results can only be validated for the reagents' corresponding mutant panels; such results tend to be mutually exclusive, and the enough concentration of mutants was required to be adjusted for a comparative analysis.