Dark field microscopy is the most specific and sensitive technique to diagnose syphilis when an active chancre or condyloma lata is present.
TPHA is a treponemal test for the serologic diagnosis of syphilis, based on the principle of passive hemagglutination. It detects IgG and IgM.
RPR test is a macroscopic, nontreponemal flocculation card test used to screen for syphilis. RPR test measures IgM and IgG antibodies to lipoidal material.
Syphilis is diagnosed by using dark field microscopy, non-treponemal tests (VDRL, RPR) or treponemal tests (TPHA, FTA-ABS).
FTA-ABS is an indirect fluorescent antibody technique used as a confirmatory test for syphilis. FTA-ABS is the first serological test to become positive following infection.