What Is A VDRL Test?
VDRL (Venereal Disease Research Laboratory) test is a blood test that screens blood sample for syphilis, a sexually transmitted infection caused by the bacterium Treponema Pallidum. The test detects antibodies produced by the immune system in response to the infection. It is a non-treponemal test, which means it does not detects the bacteria but rather the body’s response to the infection.
VDRL test is commonly used for initial screening due to its simplicity and cost effectiveness. It is often performed during prenatal checkups, pre-surgical evaluations or when a patient exhibits symptoms of syphilis. VDRL test is highly sensitive, but it is not specific to syphilis and may produce false-positive results. Positive results are usually confirmed with more precise treponemal tests such as FTA-ABS or TP-PA.
How is the Test Performed?
Sample Collection
The test requires a blood sample.
Sample Analysis
The serum is mixed with a cardiolipin-cholesterol-lecithin antigen. If there are antibodies present in the sample, they react with the antigen causing visible clumping.
Results
Results are available in a few hours to a day.
What are the symptoms that prompt this test?
VDRL test is warranted if a person exhibits symptoms of syphilis or has a risk factor.
General Symptoms
- Painless sores or ulcers (chancers) on the genitals, mouth or rectum.
- Skin rashes, particularly on the palms or soles.
- Fever, fatigue or swollen lymph nodes.
- Neurological symptoms like headaches or vision changes (in advanced stages).
- Routine screening in pregnant women to prevent congenital syphilis in newborns.
What are Normal Ranges for This Test?
VDRL is a qualitative test and does not report any numerical value. A Negative result indicates there were no syphilis antibodies detected in the sample. A Positive result means antibodies were detected and requires further testing for confirmation.
** Normal levels are dependent on a number of factors including age, gender, testing method and health condition of patient etc. Result interpretation should be done by a qualified doctor or healthcare professional.**
What Happens if Test Results Show Abnormal Levels?
Abnormal (reactive) results may indicate the following:
Syphilis Infection –A reactive result suggests syphilis. False positives can occur due to other conditions like lupus or pregnancy.
Further Testing –Confirmatory treponemal tests (FTA-ABS or TP-PA) are performed to confirm the diagnosis.
Treatment –After confirmation of syphilis, it is treated with antibiotics, typically penicillin. Treatment also depends on what stage the infection is as it can be easily treated at earlier stages. Follow up testing is done to monitor effectiveness of treatment. The doctor will interpret the results and recommend appropriate next steps based on the patient’s condition.
