Prospective, multi-centre clinic-based evaluation of four rapid diagnostic tests for syphilis

Objectives: To evaluate prospectively four rapid, point-of-care serological tests for syphilis in prenatal or high risk populations in four countries. Methods: Tests were performed on consecutive clinic attenders, using whole blood in the clinic, and whole blood and serum in the laboratory. The sensitivity and specificity of each test was evaluated, using a standard treponemal test (Treponema pallidum haemagglutination assay (TPHA) or fluorescent treponemal antibody, absorbed (FTA-ABS) as gold standard. Non-treponemal tests (rapid plasma reagin (RPR) or venereal diseases research laboratory (VDRL) tests) were also performed on all subjects at three sites. Results: The specificity of each rapid test was >95% at each site. Sensitivities varied from 64-100% and, in most cases, were lower when whole blood was used rather than serum. Conclusions: Rapid serological tests for syphilis are an acceptable alternative to conventional laboratory tests. Since they do not require equipment or electricity, they could increase coverage of syphilis screening, and enable treatment to be given at the first clinic visit.