We studied the potential usefulness of CSF treponemal tests in the diagnosis of neurosyphilis. The CSF was tested with the microhemagglutination test for Treponema pallidum (CSF-MHA-TP test) and with the CSF-FTA test by using undiluted CSF and CSF diluted in saline and in sorbent. In a prospective evaluation, of 177 nonsyphilitics, none had reactive CSF-MHA-TP tests and only one had a reactive CSF-FTA test. However, five of 15 syphilitics with no other evidence of neurosyphilis had reactive CSF-FTA tests. The CSF-FTA test reactivity appeared most likely when the titer of the serum FTA test was high. In a retrospective evaluation of syphilitics with reactive CSF-FTA tests, similar patterns of reactivity occurred in patients with and without other evidence of neurosyphilis. Without other supporting clinical or laboratory data, the diagnostic value of a reactive CSF-FTA test is unknown.
(Arch Intern Med 138:252-255, 1978)