Fig. 2 Suggested paradigm for the diagnosis of syphilis. Nontreponemal tests are exemplified by the RPR Circle Card Test and the VDRL Test, whereas commonly used treponemal tests include the particle agglutination T. pallidum (PA-TP) test and the fluorescent treponemal antibody absorbed (FTA-ABS) test. Evaluation of lesion exudates for presence of T. pallidum can be performed by darkfield microscopy or direct fluorescent antibody (DFA) staining. Adapted from reference 16.