目的探索HBs Ag和抗-HBs双阳性患者乙肝病毒S区及RT区基因变异情况。方法采用ELISA法筛选HBs Ag阳性病例,运用化学发光法进一步确认。采集研究对象血清,应用商品化离心柱法行HBV DNA提取。HBV S区和RT区变异状况采用PCR扩增后双向测序获得。采用SPSS17.0软件进行结果分析。结果实验组(HBs Ag和抗-HBs双阳性患者)HBs Ag氨基酸变异率为2.95%,对照组(HBs Ag单阳性患者)为1.80%,2组有显著差异(P=0.019)。HBs Ag N末端氨基酸变异率在实验组为3.37%,对照组为1.85%,2组有显著差异(P=0.047)。虽然HBs Ag MHR区在2组也存在显著差异(P=0.009),但这种差异可能由于该片段α决定簇第1茎环区氨基酸变异所致,因第1茎环区变异率在实验组和对照组分别为11.90%和1.79%,有显著差异(P=0.002)。实验组α决定簇特异性变异位点为I126V、A128V、Q129H、M133I、F134L,而对照组为G145E/R。实验组RT区氨基酸变异率为2.86%,对照组为2.35%,2组无显著差异(P=0.229)。结论 HBV S区MHR的α决定簇第1茎环区氨基酸高变异率可能是HBs Ag和抗-HBs双阳的原因之一,但研究结论尚需进一步验证。 Objective To explore the genetic variation of hepatitis B virus S region and RT region in HBs Ag and anti-HBs double positive patients. Methods HBsAg positive cases were screened by ELISA and further confirmed by chemiluminescence. Serum samples were collected for HBV DNA extraction using commercial centrifuge column. The variation of HBV S region and RT region was obtained by two-way sequencing after PCR amplification. SPSS17.0 software was used to analyze the results. Results The amino acid mutation rate of HBsAg in experimental group (HBs Ag and anti-HBs double positive patients) was 2.95%, while in control group (HBs Ag single positive patients) was 1.80%. There was significant difference between the two groups (P = 0.019). The mutation rate of N-terminal amino acid of HBs Ag was 3.37% in the experimental group and 1.85% in the control group, with significant difference between the two groups (P = 0.047). Although there was a significant difference in HBs Ag MHR region between the two groups (P = 0.009), this difference may be due to the amino acid variation in the first stem-loop region of α-determinant of the fragment. Because of the variation rate of the first stem-loop region in the experimental group And control group were 11.90% and 1.79%, there was a significant difference (P = 0.002). Experimental group α determinant specific mutation sites for I126V, A128V, Q129H, M133I, F134L, while the control group was G145E / R. The mutation rate of amino acid in RT area was 2.86% in experimental group and 2.35% in control group, there was no significant difference between two groups (P = 0.229). Conclusions The high mutation rate of amino acid in the first stem-loop region of α-determinant of MHR in HBV S region may be one of the causes of HBsAg and anti-HBs double positive. However, the conclusion of the study still needs further verification.