Abstract:

Objective To investigate the proper method for detecting hepatitis B virus surface antigen (HBsAg) in infants of 0-7 d. Methods A total of 137 serum samples from infants of 0-7 d were collected from Shanghai Children's Medical Center. The 101 of 147 cases had been injected with hepatitis B vaccine, and the other 36 cases had not been injected. Electro-chemiluminescence immunoassay was used to detect HBsAg. The bilirubin and hemoglobin were detected simultaneously. All the samples were detected and reviewed by enzyme-linked immunosorbent assay (ELISA). Moreover, the medical history and the percentage of hepatitis B vaccine injection were analyzed and calculated for false positive rate by correlation analysis. Resutls The 55 cases exhibited positive results in vaccine injection group, and the positive rate was 54.5%. A total of 7 cases in non vaccine injection group showed positive results, and the positive rate was 19.4%. Risk analysis showed that odds ratio (OR) was 4.953 (95% confidence interval: 1.987-12.350). Bilirubin and hemoglobin did not affect the false positivity. All of these false positive samples above were confirmed negatively by ELISA. Conclusions ELISA is the right way to detect HBsAg in infants of 0-7 d. Hepatitis B vaccine injection could result in false positivity by electro-chemiluminescence immunoassay, which should be performed after 1 week, and should be repeated if false positive result exhibits.

Key words: Hepatitis B virus surface antigen, Electro-chemiluminescence immunoassay, False positivity