[Evaluation of different methods in determination of low level HBsAg].

Objective: To evaluate chemiluminescent immunoassay (CLIA), electrochemiluminescent immunoassay (ECLIA) and ELISA in determination of low level HBsAg.

Methods: According to the standard of CLIA Architect i2000, 70 samples were divided into three groups by HBsAg concentration : <1 ng/ml, 1-5 ng/ml and >4 ng/ml. The samples were also determined by ECLIA MODULAR170 and ELISA, and the results were compared with those measured by CLIA Architect i2000.

Results: The concordance rates of ECLIA MODULAR170 with Architect i2000 was 79.2% for <1 ng/ml group, 100% for 1-5 ng/ml group, 100% for >4 ng/ml group. And the concordance rates of ELISA with Architect i2000 was 0 % for <1 ng/ml group, 45.5% for 1-5 ng/ml group and 100 % for >4 ng/ml group.

Conclusion: For determination of low level HBsAg,CLIA Architect i2000 and ECLIA MODULAR170 have high credibility. ELISA is also credible when HBsAg >5 ng/ml, but not for low level HBsAg, especially for HBsAg <1 ng/ml.