Comparative Value of the Serological Tests Using Specific Treponemal Antigens in the Diagnosis of Syphilis

Abstract

In this study of the comparative value of serologic tests for syphilis the TPI test using the virulent live T pallidum as its specific antigen, has been observed to be less reactive or "less sensitive" than the "VDRL slide test using the non- treponemal Cardiolipin antigen in "early stage of Syphilis". The sensitivity of the TPI test was found to improve to the ideal 100 percent in late stage of syphilis in which the serologic tests for syphilis have the greatest diagnostic value. In non- syphilitic conditions, the non-reactivity or the "specificity" of the TPI test was also found to be 100 percent in contrast to that of the VDRL test. Therefore the TPI test is considered as the ideal test to be made available in the sero-diagnosis of syphilis. But its technique is too difficult and costly to be established as a routine diagnostic test in all laboratories. However it can be performed in a Central or regional reference laboratory in India at least as a "supplementary reference verification test, by a modified technique of it successfully tried in this study.