The overall objectives of this study are to determine the performance characteristics of a candidate rapid point-of-care test (Syph-Check cassette format) for Treponema pallidum antibodies in serum, plasma and finger stick whole blood obtained from females and males attending sexually transmitted diseases (STD) clinics, family planning / reproductive health clinics, and physician's office; and to compare the performance of this new, rapid test to currently licensed laboratory based tests, the non-treponemal RPR and a Treponemal ELISA or TPPA test.