The effect of treatment on the Treponema Pallidum Haemagglutination test in early syphilis.

The response of the Treponema Pallidum Haemagglutination Assay (TPHA) to treatment was studied in 61 cases of early infectious syphilis. In none of the 55 cases of early syphilis in which the pre-treatment TPHA was positive did the TPHA test become consistently negative after treatment. In primary and early latent syphilis it was not possible to demonstrate any significant changes, but in some cases of secondary syphilis a significant and rapid fall in TPHA titre occurred with treatment. It is suggested that the post-treatment TPHA titre need not necessarily reflect the stage at which the disease was arrested.