For syphilis patients with the following clinical symptoms (e.g., cranial nerve dysfunction, auditory or ocular abnormalities, meningitis, stroke, acute or chronic mental status changes, loss of vibriosis), or non-specific syphilis spirochete antibodies (e.g., RPR, TRUST) at titers greater than 1:32, or with concomitant HIV (human immunodeficiency virus) infection, further lumbar puncture of cerebrospinal fluid is required to rule out neurological Syphilis. Laboratory testing of cerebrospinal fluid is helpful in the diagnosis of neurosyphilis; however, no single test can be used for the diagnosis of neurosyphilis in all cases. The diagnosis of neurosyphilis relies on a combination of serologic tests, cerebrospinal fluid (CSF) tests (CSF cell count or protein level, CSF-VDRL), and neurologic symptoms and signs results. CSF-VDRL is highly specific, but not sufficiently sensitive. A diagnosis of neurosyphilis can be considered if the patient has neurological signs or symptoms and is also positive for CSF-VDRL (in the absence of blood contamination). Neurosyphilis needs to be considered if CSF-VDRL is negative but there are neurosyphilis symptoms, positive serologic tests, and abnormal cerebrospinal fluid cell counts and/or protein levels. In such cases, it is necessary to use the CSF FTA-ABS test as an additional evaluation indicator. the CSF FTA-ABS test is more sensitive than the CSF-VDRL as a neurosyphilis diagnosis, but less specific. In persons without specific neurological signs and symptoms, if the CSF FTA-ABS test is negative, neurosyphilis is unlikely.