The CSF-VDRL test is used to help diagnose neurosyphilis. It looks for substances called antibodies, which are sometimes produced by the body in reaction to the syphilis-causing bacteria.
Venereal disease research laboratory slide test - CSF
How the Test is Performed
A sample of spinal fluid is needed. For information on how this is taken, see: Lumbar puncture (spinal tap)
Why the Test is Performed
The CSF-VDRL test is done to diagnose syphilis in the brain or spinal cord. Brain and spinal cord involvement is usually a sign of late-stage syphilis.
Blood screening tests (VDRL and RPR) are better at detecting middle-stage (secondary) syphilis.
A negative result is normal.
However, false-negatives can occur. This means you can have syphilis even if this test is normal. Therefore, a negative test does not always rule out the infection. Other signs and tests may be used to diagnose neurosyphilis.
What Abnormal Results Mean
A positive result is abnormal and is a sign of neurosyphilis.
Tramont EC. Treponema pallidum (Syphilis). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2009:chap 238.
Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.