Syphilis is one of the most fascinating diseases of humans. Widespread use of antibiotics now has reduced the incidence of early syphilis and recognized new cases of late syphilis have decreased. Serological tests are the basis for the diagnosis of latent syphilis. They vary in their sensitivity and specificity. While non-treponemal tests (VDRL and RPR) are most frequently used as screening procedures, treponemal tests (FTA-ABS and TPHA) are considered to be highly sensitive and specific. MATERIALS AND METHODSIn this study 100 serum samples collected from the patients attending STD Department, King George Hospital, Visakhapatnam. Samples were subjected to VDRL, RPR and Micro-TPHA tests to evaluate the sensitivity and specificity of Micro-TPHA test in patients with various stages of syphilis and to evaluate the efficacy of Micro-TPHA to confirm the diagnosis of syphilis and to rule out biological false positive reactions or false negative reactions of VDRL tests. RESULTSThree tests (VDRL, RPR and Micro-TPHA) were applied to all 100 patients. Among them 85 were VDRL reactive, 84 were RPR positive and 89 were TPHA positive. In them males were more in number, in 3 tests with respect to age, (21-30) age group patients showed predominance. Out of 100 patients, 81 sera were positive for all three tests and one serum sample was VDRL reactive, but RPR and TPHA were non-reactive. This may be a false positive reaction. The following tables showed the sensitivity and specificity of each test and also the sensitivity of each test in various stages of syphilis. CONCLUSIONIt is concluded as by performing TPHA test, false positive reactivity of VDRL test could be detected. Even in the cases of treated primary and secondary syphilis, TPHA was reactive. The lipoidal antigen tests primarily reflect disease activity and serial quantitative performance of these tests used to measure the treatment response.