CSF VDRL test

Alternative names
Venereal Disease Research Laboratory slide test - CSF

Definition
The CSF-VDRL test is used to diagnose neurosyphilis (syphilis associated with brain or neurologic involvement). This test detects the presence of reaginic antibodies in cerebrospinal fluid (CSF), which is the fluid that surrounds the spinal cord and brain.

How the test is performed
The test is performed on a CSF sample obtained by lumbar puncture (spinal tap).

How to prepare for the test

The procedure is a lumbar puncture (spinal tap). Before the procedure, you will be asked to review the risks and sign a consent form. After the lumbar puncture is done, you will be asked to remain lying down flat for 6 hours.

Infants and children:
The preparation you can provide for this test depends on your child’s age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following:

How the test will feel

You will be asked to lie on your side in the fetal position with your legs curled towards your chest. The area where the needle will be inserted (in your lower back) will be thoroughly cleaned. The scrub will feel cold and wet.

You will then receive an injection at the site with local anesthesia which may sting or burn when first injected. There will be a hard pressure sensation when the needle is inserted, and there is usually some brief pain as the needle goes through. This pain should stop in a few seconds.

Overall, discomfort is mild to moderate. The entire procedure usually takes about 30 minutes but may take longer. The actual fluid collection only takes a few minutes.

Why the test is performed
The CSF-VDRL test is used to diagnose syphilis in the brain or spinal cord. As this usually reflects late (tertiary) syphilis, the blood screening tests such as VDRL or RPR may be falsely negative.

Normal Values
Because this test has a high rate of false negatives, a negative test does not rule out neurosyphilis. Other markers of inflammation such as elevated protein levels or excess white blood cells may suggest neurosyphilis even when the CSF-VDRL is negative.

What abnormal results mean
A reactive VDRL test when using a CSF sample indicates neurosyphilis.

What the risks are

     
  • Risks of lumbar puncture include:       o Hypersensitivity (allergic) reaction to the anesthetic       o Discomfort during the test       o Headache after the test       o Bleeding into the spinal canal       o Brain herniation (if performed on a person with increased intracranial pressure) which may result in brain damage or death       o Damage to the spinal cord or nerve roots

Special considerations
Since the CSF VDRL test can have false negative results, additional tests such as protein levels and white blood cell counts may be done on the spinal fluid to diagnose neurosyphilis.

Johns Hopkins patient information

Last revised: December 4, 2012
by Amalia K. Gagarina, M.S., R.D.

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