Comparison on the performance of 4 ELISA kits for the diagnosis of syphilis

Objective To evaluate the performance of 4 home-made enzyme-linked immunosorbent assay(ELISA) kits for the diagnosis of syphilis,and provide the reference for choosing diagnosis reagent in clinic.Methods A total of 180 serum samples were detected by rapid plasma reagin(RPR) circle card test,Treponema pallidum particle agglutination(TPPA) assay and 4 ELISA kits(labeled A,B,C and D).The sensitivity,specificity,positive predictive value and negative predictive value of 4 ELISA kits were calculated statistically with the results of TPPA as reference.Results Of 180 serum samples,58 were positive for RPR,84 were positive for TPPA,and 95 were negative for both RPR and TPPA.The positive rates were 46.67%(84/180) for TPPA,44.44%(80/180) for ELISA A kit,45.00%(81/180) for ELISA B kit,45.00%(81/180) for ELISA C kit and 28.33%(51/180) for ELISA D kit.There were significant differences between ELISA D kit and TPPA,as well as the other ELISA kits(P0.01).The worst sensitivity was found in ELISA D kit(57.14%),in comparison with that in the other ELISA kits(94.05%-95.24%).The specificities of 4 ELISA kits were ideal(96.88%-100.00%).Conclusions The sensitivity in certain home-made ELISA kit is not good.The pretest with quality control sera is necessary before the clinical application of the ELISA kit.