Clinical value of combined application of three serological detective methods for diagnosis of treponema pallidum infection

Objective To explore the clinical value of combined application of three serological detective methods for the diagnosis of treponema pallidum(TP) infection.Methods All of 6 483 clinical specimens underwent routine TP antibody screening with enzyme linked immunosorbent assay(ELISA) method;positive samples were further tested by toluidine red unheated-serum test(TRUST) and treponema pallidum particle agglutination(TPPA).Results Among 342 TP antibody screening positive specimens(TP-ELISA),313 positive results were reseted by TPPA.The positive rate of TPPA was 91.5%(313/342).Of 265 positive samples detected with TRUST titer,264 were positive by TPPA.Forty-nine out of 77 TRUST titer negative samples were positive by TPPA.Of 29 samples,which were positive results tested by TP-ELISA but were negative by TPPA,28 cases were lower than 1∶ 2(negative).Conclusions TP-ELISA shows better sensibility,simple operation and easy automation,so it tends to displace TRUST as routine screening method,but it exists false positive(8.2% ),especially for old people(≥60 years old) .TP-ELISA screening positive specimens should be further tested by TPPA;if TPPA negative,test it again after two weeks.TRUST is not suitable as a routine screening method,but TRUST titer may be used to observe therapeutic effect.