The Venereal Disease Research Laboratory (VDRL) test is performed to determine whether or not you have syphilis. The bacterium, Treponema Pallidum, infects by penetrating the lining of the mouth or genital area, which results in syphilis.
The VDRL test measures the antibodies that your body may produce as a result of coming in contact with the bacteria that causes syphilis. Testing for these antibodies helps your doctors know if you are infected.
Why Doctors Perform a VDRL Test?
Your doctor may recommend this test if you:
- Have signs and symptoms of syphilis
- Are pregnant
- Are treated for another sexually transmitted infection such as gonorrhea
- Have engaged in high-risk sexual activity Are affected by HIV
- Have already treated for syphilis
What Are the Symptoms of Syphilis?
The symptoms of syphilis can be mild to severe depending on the extent of the infection. However, in some cases, syphilis may not cause any symptoms for several years.
The primary symptoms of syphilis include:
- A small, painless sore
- A skin rash that does not itch
- Swelling in the lymph nodes near the sore
The secondary symptoms of syphilis include:
- A red or reddish-brown non-itchy rash that spreads to the entire body including the soles of the feet and palms of the hands
- Sore throat
- Patchy hair loss
- Muscle aches and headaches
- Weight loss
- Genital, oral, and anal wart-like sores
The tertiary symptoms of syphilis include:
- Damage to the blood vessels, joints, heart, bones, and liver
- Gummas or soft tissue swellings
How Is the Test Performed?
This test requires your blood sample. Your doctor will draw your blood from the back of your hand or your vein at the crease of the elbow. The collected blood sample will be sent to the laboratory for testing antibodies. Your doctor may test your spinal fluid if they suspect that your infection has spread to your brain. You do not have to stop taking medicines or fast before the test unless stated by your doctor.
Understanding the Results of Your VDRL Test
If your blood sample test shows negative, then your blood does not contain syphilis antibodies, and you are not infected with the bacteria. If your test shows positive results for syphilis antibodies, you may have syphilis. However, your doctor will recommend another test called the treponemal test to confirm your result. This test is performed to check whether your immune system has produced specific antibodies as a result of coming in contact with the syphilis-causing bacterium.
Potential for False Positives and Negatives
The VDRL test may not be accurate in some cases. Your body requires a long time to produce syphilis antibodies. You may get false-negative results if your body has not produced specific antibodies even if you have the infection. False-positive results are possible if you have:
- Lyme disease
- Systemic lupus erythematosus
- Certain types of pneumonia
- Used IV drug
The syphilis antibodies can stay in your body even after you have been treated for the disease and in such cases, you may get false-positive test results.
Risks of Taking the VDRL Test
The risks of this test are not severe. You may experience slight discomforts such as:
- Mild pain when drawing blood
- Minor bruising or bleeding after drawing blood
Very rarely, you may develop an infection or inflammation of the vein as a result of the VDRL test.