ABSTRACT
183 sera from persons presumed free of syphilitic infection [80 sera from clinically free persons and 103 sera from patients with either physiological or pathological disorders] and 67 sera from syphilitic patients at various stages of infection [41 sera from untreated patients and 26 sera from treated cases] were screened by WR, Kahn, VDRL and TPHA tests- The investigations showed that in primary stage of untreated syphilitics before the appearance of chancre, the VDRL sensitivity [55.6%] is higher than TPHA sensitivity [33.3%], while after the appearence of chancre the sensitivity of TPHA [90.9%] is higher than VDRL [84.6%]. In primary and teriary stages of untreated syphiliticsd the sensitivities of TPHA and VDRL tests were much higher than WR, Kahn tests, while in secondary stage of untreated syphilis, the sensitivities of the former tests are about equal to the latter ones. TPHA test revealed a higher incidence of positive results in the three stages of the treated syphilitics, when compared with the VDRL, Kahn and WR tests, In cases of treated syphilitics [primary, secondary and teriary stages], seroverasal of TPHA test happened far less frequently than Kahn, WR and VDRL tests