新型ELISA检测戊型肝炎病毒IgM抗体的敏感度与特异度评价

Evaluation of the Sensitivity and Specificity of a New ELISA for Detecting of IgM Antibody against Hepatitis E Virus

目的 评估基于戊型肝炎病毒（HEV）主要免疫表位多肽及其截短多肽的新型ELISA检测抗HEV IgM的敏感度与特异度.方法 根据抗HEV抗体与主要免疫表位多肽的高反应性以及与截短多肽的不反应性,分别以两种多肽为包被抗原,建立新型ELISA法,检测2007-2012年收集的612例可疑HEV感染者血清抗HEV IgM,并与万泰HEV IgM抗体诊断试剂盒检测结果比较,结果不一致血清用免疫印迹法（Western blotting）确认,χ^2检验比较两种试剂灵敏度和特异度.结果 抗HEV IgM检测中,新型ELISA阳性326例,阴性286例;万泰试剂阳性370例,阴性242例;两种试剂同时阳性320例,同时阴性236例.在万泰试剂阳性而新型ELISA阴性的50例中,Western blotting证实阳性21例,阴性29例;在万泰试剂阴性而新型ELISA阳性的6例中,Western blotting显示阳性与阴性各3例.以两种试剂同时阳性或Western blotting阳性为标准,万泰试剂与新型ELISA灵敏度分别为99.1％（95％ CI：0.972-0.998）和93.8％（95％ CI：0.907-0.961）,差异有统计学意义（χ^2=13.988,P＜0.001）;特异度分别为89.2％（95％ CI：0.847-0.925）和98.9％（95％ CI：0.965-0.997）,差异有统计学意义（χ^2=22.466,P＜0.001）.结论 与万泰试剂相比,新型ELISA检测抗HEV IgM敏感度略低,但特异度较好,可减少抗HEV IgM检测中的假阳性.

Objective To evaluate the sensitivity and specificity of a new ELISA based on the immunodominant polypeptide and truncated polypeptide derived from hepatitis E virus （HEV） in detection of anti HEV IgM.Methods Based on the high reactivity of anti-HEV to the immunodominant polypeptide and the poor reactivity of anti-HEV to the truncated polypep tide,a new ELISA was developed with the two polypeptides as coating antigens separately.Totally 612 sera from persons with suspected HEV infection,from 2008 to 2012,were tested for anti-HEV IgM in parallel by the new ELISA and Wantai kit,and the discordant sera were confirmed by Western blotting.The χ^2 test was used to compare the sensitivity and specific ity of two assays.Results Anti-HEV IgM was positive in 326 samples and negative in 286 other samples with the new ELISA,while anti HEV IgM was positive in 370 sera and negative in 286 other samples with Wantai kit; 320 were positive and 236 were negative in both assays.Of the 50 sera positive by Wantai kit but negative by the new ELISA,21 and 29 were tested to be positive and negative respectively by Western blotting.Of the 6 sera negative by Wantai kit but positive by the new ELISA,Western blotting showed that 3 each were positive and negative.Based on positive in both assays or in Western blotting,the sensitivities of Wantai kit and the new ELISA were 99.1% （95% CI：0.972-0.998） and 93.8% （95% CI：0.907-0.961）,respectively （χ^2=13.988,P〈0.001）,and the specificities were 89.2% （95% CI：0.847-0.925） and 98.9% （95 % CI：0.965-0.997）,respectively （χ^2 =22.466,P〈0.001）.The differences were statistically significant.Conclusion Compared with the Wantai kit,the new ELISA had relatively lower sensitivity but had higher specificity,which may be used to exclude false positives in the detection of anti HEV IgM.