What is VDRL Test?

VDRL is a screening test for Syphilis. Blood is drawn from the inner side of the elbow or back of the hand through venipuncture in an air-tight vial or syringe. The blood sample is then prepared and analyzed for antibodies the body produces in response to Syphilis infection. This process is fairly painless.

VDRL test results are assessed as “positive” or “negative” based on the presence or absence of antibodies to the T. pallidum bacteria in the blood sample. A negative test result for a VDRL indicates that no syphilis antibodies were found in the blood and is considered to be the normal value. If your results are positive, your doctor will order a more specific test called a treponemal test to confirm the results.

The VDRL test is used as a screening tool for Syphilis. Early symptoms of Syphilis infections include a small, painless sore, swelling in the lymph node near the sore, and a skin rash that does not itch. Other symptoms may include fever, muscle ache, headaches, sore throat, swollen glands, fatigue, patchy hair loss, sores that resemble anal, oral, and genital warts, and a non-itchy rash that starts on the trunk and spreads to the entire body, including the palms of the hands and soles of the feet.

VDRL test results depend on the stage of the infection, and early stages might show a false negative. In the case of a positive test, Syphilis specific test is required for confirmation.

A positive VDRL test result may indicate the presence of Syphilis infection. The infection progresses through four stages: early, secondary, latent, and tertiary. The condition is curable with prompt diagnosis and treatment in the early stages. However, if not treated, it can result in disabilities, neurological problems, and even death.

Abnormal WBC count and protein levels in CSF usually decrease in six months. CSF VDRL test results, however, remain reactive for at least two years. With treatment for primary and secondary Syphilis, VDRL test titers should decline fourfold within three to six months and latent Syphilis within 12-24 months.

A negative VDRL test typically indicates that there are no antibodies for Syphilis in the blood sample, ruling out the possibility of infection. However, VDRL is likely to give a false negative result when tested in the early stages. As a result, people who are at high risk of syphilis should have routine screening tests every three months.

A positive VDRL test indicates syphilis infection. When diagnosed and treated early on, it can be effectively cured. The preferred treatment for syphilis at all stages is penicillin, an antibiotic medication. If you are allergic to penicillin, your doctor may prescribe another antibiotic, such as doxycycline or azithromycin, or recommend penicillin desensitisation.

False-positive VDRL test results can occur in certain acute and chronic infections, autoimmune diseases such as lupus and rheumatoid arthritis, during pregnancy, and after vaccination.

The full form of VDRL is Venereal Disease Research Laboratory, which is a blood test used to screen for syphilis, an STI caused by the bacterium Treponema pallidum.

A "reactive" test result indicates that the antibodies to T. pallidum bacteria are present in the blood sample, indicating the presence of syphilis infection. A "non-reactive" test result indicates the absence of antibodies, thereby ruling out infection.