The TPI and FTA-ABS tests in treated late syphilis

Abstract

Sixty-seven patients who were diagnosed and treated 13 or more years ago for latent or late syphilis were retested with use of several serological tests for syphilis. At the time of original diagnosis, all patients were active in cardiolipin reagin tests and in the Treponema pallidum immobilization (TPI) test. Seventy-three per cent of patients were still reactive in 1 or more cardiolipin reagin tests and that 90% had retained TPI reactivity. In the newer fluorescent treponemal antibody-absorption (FTA-ABS) test, 98% were reactive. FTA-ABS test is more sensitive than th TPI test. Neither the FTA nor the TPI test, as presently performed, may be used as an index of therapeutic response, since both tests show reactivity 13 or more years after presumably adequate treatment.