Information about the VDRL
We Have to Know about the VDRL
- VDRL is a screening test for syphilis that measures antibodies that can be produced by Treponema pallidum, the bacteria that causes syphilis.
How the Test is Performed:
- The test is usually performed on blood.
- If an individual is suspected of having brain involvement with syphilis (neurosyphilis), the VDRL test may be performed on spinal fluid.
How the Test Will Feel:
- When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed:
- This test is used to diagnose syphilis.
- Syphilis is a highly treatable infection.
- In addition to screening individuals with signs and symptoms of sexually transmitted diseases, syphilis screening is a routine part of prenatal care during pregnancy.
- A negative test is normal and means that no antibodies to syphilis have been detected.
- The screening test is most likely to be positive in secondary and latent syphilis. During primary and tertiary syphilis this test may be falsely negative.
What Abnormal Results Mean:
- A positive test result may mean you have syphilis. If the test is positive, the next step is to confirm the results with an FTA-ABS test, which is a more specific syphilis test.
- The VDRL test’s ability to detect syphilis depends on the stage of the disease. The test’s sensitivity to detect syphilis nears 100% during the middle stages; it is less sensitive during the earlier and later stages.
The following conditions may cause a false positive test:
- Lyme disease
- Certain types of pneumonia
- Systemic lupus erythematosus
Risks of VDRL
- Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
- The body does not always produce antibodies specifically in response to the syphilis bacteria, so this test is not always accurate.