The TPI and FTA-ABS Tests in Treated Late Syphilis

Abstract

Sixty-seven patients who had been 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 had been reactive in cardiolipin reagin tests and in the Treponema pallidum immobilization (TPI) test. It was found that 73% of patients were still reactive in one 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. These results indicate that the FTA-ABS test is more sensitive than the 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 persumably adequate treatment .