Test sent to Mayo Medical Laboratories. If the screen is positive, a VDRL Titer (Mayo VDSFQ) will be performed at an additional charge. By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated. A reactive CSF-VDRL, free of blood or other contamination almost always indicates past or present CNS syphilis. A biological false positive CSF-VDRL test result for syphilis is rare. The CSF-VDRL syphilis test is not an appropriate screening test because, although specific, it is not sensitive. A negative result can also occur in some neurosyphilis patients, so the test cannot be used to rule out neurosyphilis. The Centers for Disease Control recommend that the CSF-VDRL be performed ONLY when a patient has a seropositive treponemal test (reactive serum FTA-ABS). CSF FTA-ABS testing is not recommended by the CDC, but may be used to rule out neurosyphilis if the CSF FTA-ABS is reported as nonreactive.