Comparative Study for Serological Diagnosis of Syphilis between VDRL and TPHA

Abstract

We performed serological test of 650 sera to compare the accuracy between VDRL and TPHA test for sensitivity, specificity, positive predicitive value (PPV), and negative predictive value (NPV). The discordant results were confirmed by FTA-ABS. We found that the sensitivity and specificity of VDRL were 94.3% and 96.7%, respectively. TPHA was found as 100% sensitivity and 99.6% sensitivity. The negative predictive value decreased when the prevalence of syphilitic infection increased. This limitation cause more cases of syphilitic infection which not diagnosed by VDRL. We ecommended to use TPHA instead of detecting syphilitic infection particularly in high risk population