In patients having primary and secondary syphilis, adequately treated, the Treponema pallidum immobilization (TPI) test and other serologic tests for syphilis (STS) may be reactive or nonreactive.* The test results to some extent depend on the length of time after treatment the blood was drawn, the individual's response to treatment, and the stage of his treatment. It has been observed that the TPI test generally remains reactive for longer periods of time after treatment than the commonly used STS.†
This study of patients with treated early symptomatic syphilis was undertaken to compare the reactivity of the TPI test, as modified,5 with the VDRL slide test quantitative. Also, attempts were made to ascertain temporal relationships of results of the TPI test and the VDRL slide test to adequate treatment for the disease in its dark-field positive stages.
CLINICAL MATERIAL
One hundred eighty-eight patients, who had been