梅毒抗原血清学试验筛查在实验室诊断中的应用

Application of reverse sequence screening for syphilis in laboratory diagnosis

目的探讨梅毒逆向筛查程序方案,分析其在实验室诊断及梅毒筛查防治中的应用价值。方法应用梅毒螺旋体明胶颗粒凝集试验（TPPA）、梅毒螺旋体抗体酶联免疫吸附试验（TP-ELISA）、甲苯胺红不加热血清学试验（TRUST）,同时对2015年1至6月杭州师范大学附属医院各门诊及病房梅毒筛查者23 389份标本进行检测。以TPPA为标准,方法间一致性比较采用Kappa检验,通过各方法的灵敏度、特异性、总符合率的比较,分析TP-ELISA作为初筛方法的梅毒逆向筛查程序的可行性,并进一步统计TP-ELISA的S/CO值与TPPA阳性结果的相关性,简化逆向筛查程序。结果 23 389份标本中,TPPA筛查阳性率为3.38%（790份）,TP-ELISA、TRUST筛查阳性率分别为3.63%（849份）、1.89%（443份）。TP-ELISA与TPPA在梅毒筛查时具有非常好的一致性（K=0.954）,TRUST与TPPA一致性一般（K=0.693）,TP-ELISA的灵敏度为99.1%,大于TRUST的灵敏度54.7%,差异有统计学意义（P〈0.01）。统计发现,当TP-ELISA的S/CO值≥5.0时,其结果与TPPA结果完全一致;当TP-ELISA的S/CO值分布在1.0-4.99之间时,有66例假阳性;当TP-ELISA的S/CO值≤1.0时,所有样本中存在7例假阴性（6例样本TRUST阳性）。结论 TRUST敏感度较低,单独作为梅毒筛查不利于大量隐性梅毒患者的发现;TP-ELISA灵敏度和特异性较高,与TPPA一致,其操作简单,可以自动化批量检测,成本低,适用于临床大样本筛查。

Objective To evaluate the value of reverse sequence screening for syphilis in laboratory diagnosis.Methods Samples were collected from the Affiliated Hospital of Hangzhou Normal University during the period of January to June 2015,and detected for Treponemal infections by Toluidinered unheated serum test（TRUST）,treponema pallidum enzyme-linked immunosorbent assay（TP-ELISA）and treponema pallidum particle agglutination test（TPPA）,with TPPA as a gold standard.The sensitivity,specificity and total accordance rate of the methods were analyzed,with Kappa test to compare the percent agreement and corresponding values.S/CO value of TP-ELISA compared to TPPA results was performed to simplify the reverse sequence screening.Results Out of 23389 samples,the positive rate of TPPA was 3.38%（790）,and the rates of TP-ELISA and TRUST were 3.63%（849）and1.89%（443）respectively.Compared to TPPA assay,the corresponding kappa values were K=0.954 for TP-ELISA and K=0.693 for TRUST.The sensitivities of TP-ELISA and TPPA were 99.1% and 54.7%,with the difference（P0.01）statistically significant.66（S/CO∶1-4.99）samples was falsely reported as positive and 7（S/CO≤1.0）samples falsely reported as negative by TP-ELISA.Conclusion It is unadvisable to use TRUST for screening test alone due to its low sensitivity.TP-ELISA has a high sensitivity and specificity similar to TPPA and it is simple,inexpensive and easy for batch testing.We suggest clinical laboratories use TP-ELISA and TRUST for screening test simultaneously,with positive samples further confirmed by TPPA.This reverse sequence screening for syphilis is more sensitive than the traditional algorithm.We can set up the positive results of S/CO value to reduce the proportion for further confirmation by TPPA.