Abstract: Objective　To use neutralization confirmatory test to confirm and analyze the results of weak reactive hepatitis B surface antigen (HBsAg) determination by electrochemiluminescence immunoassay (ECLIA).  Methods　A total of 100 weak reactive HBsAg positive samples (1.00＜ COI ＜50.00) were detected by ECLIA，and confirmed by neutralization confirmatory test. The results were analyzed.  Results　Among the 100 weak reacitve HBsAg positive samples，87 samples (87.0％) were confirmed，10 samples (10％) were negative，and 3 samples (3.0％) were uncertain．According to the receiver operating characteristic (ROC) curve，when the COI was 1.97，the specificity was 100.0％，and the sensitivity was 83.9％. Conclusions　The neutralization confirmatory test can be used as the further means to confirm the samples with weak reactive HBsAg. ECLIA shows high sensitivity and specificity on weak reactive HBsAg positive samples．When COI＞2.00，generally it is unnecessary to do the neutralization confirmatory test and could exclude the possibility of false-positivity

Key words: Neutralization confirmatory test, Hepatitis B surface antigen, Weak reaction, Electrochemiluminescence immunoassay