The usefulness of toluidine red unheated serum test in the diagnosis of HIV-negative neurosyphilis.

We retrospectively analyzed the Venereal Disease Research Laboratory test, Treponema pallidum particle agglutination test, and toluidine red unheated serum test (TRUST) in 41 cases of HIV-negative neurosyphilis and 34 non-neurologic syphilitic patient and found that serum-TRUST titers could be the indication of lumbar puncture in syphilitic patients and a reactive cerebrospinal fluid-TRUST is considered diagnostic to neurosyphilis.