Evaluation of three kinds of methods for clinical diagnosis of Treponema pallidum

Objective To evaluate the sensitivity and specificity of enzyme linked immunosorbent assay(ELISA),treponema pallidum particle agglutination assay(TPPA) and rapid plasma reagin test(RPR) in clinical diagnosis of treponemal infection.Methods Sera from 4825 syphilis patients were detected by ELISA,TPPA and RPR.The results obtained with ELISA and RPR were compared with those obtained with TPPA.The positive and false positive rates of different methods were calculated.Results The positive rate detected by ELISA and RPR and the method of superposition of TPPA and RPR were 95.06%(385/405),70.12%(284/405) and 67.90 %(275/405) respectively.The false positive rate of the above three methods were 0.66%(29/4 420),0.45%(20/4 420) and 0.11(5/4 420) respectively.Conclusion ELISA is a highly sensitive and specific serological method and can be used as confirmatory test for the diagnosis of treponemal infection.The result of ELISA and TPPA is well correlated.RPR can only be used as supplementary test.Combined analysis of the results of the three methods will decrease the false positive rate.