Comparative evaluation of nine different enzyme-linked immunosorbent assays for determination of antibodies against Treponema pallidum in patients with primary syphilis

Nine different enzyme-linked immunosorbent assays (ELISAs) with a sonicate or recombinant proteins of Treponema pallidum as antigen have been evaluate d comparatively by testing 52 highly selected sera from patients with prima ry syphilis, all negative in the microhemagglutination test for T. pallidum (MHA-TP). Eight tests exhibited greater sensitivity (48.5 to 76.9%) than t he commonly used Venereal Disease Research Laboratory test (44.2%). Higher sensitivity could be related to (i) the volume and dilution of the serum, ( ii) the design of the assay (capture and competitive tests showed higher se nsitivity than sandwich-based assays), and (iii) the ability to detected sp ecific immunoglobulin M antibodies. The specificity of the ICE Syphilis and the Enzygnost Syphilis tests was 99.5 and 99.8%, respectively, as determin ed by routine testing of 2,053 unselected sera in comparison,vith the MHA-T P test. ELISAs tested offered high sensitivity in patients with primary syp hilis; however, recommendations to use these tests as screening assays do n eed further data on specificity and reactivity in late stages of the diseas e.