Background Comparison of diagnostic efficiency of four ELISA kits for determining HBsAg. Methods Collecting 348 serum samples from clinical laboratory of Renmin Hospital of Wuhan University without specific gender and age requirements, determining HBsAg by the four ELISA kits, simultaneously. Confirmatory test was carried out when the initial results are positive. Results 329 out of 348 samples results were consistent (94.5%), 152 out of 329 were positive, and 177 out of 329 were negative, and all the positive results can be confirmed; 19 samples were not consistent (5.5%), and only 1 sample was confirmed by the confirmatory test. After calculation, the diagnostic efficiencies of the four ELISA kits (Beijing Wantai, Xiamen Xinchuang, Zhuhai Lizhu, and Shanghai Kehua) were 98.6%, 98.0%, 99.7%, and 97.4%, respectively, the sensitivities were 100%, 99.4%, 99.4%, and 100%, respectively, the specificities were 97.5%, 96.9%, 100%, and 95.4%, respectively, the false positive rates were 2.5%, 3.1%, 0, and 4.6%, respectively, and the false negative rates were 0, 0.6%, 0.6%, and 0, respectively. All the initial absorbencies of the false positive samples were less than 1.0. Conclusion The diagnostic efficiency of Lizhu is the highest, while Kehua is the lowest. False positive or false negative results would take place in any of the kits, an HBsAg confirmatory test is essential for initially positive samples, especially with absorbance