Venereal Disease Research Laboratory (VDRL) Test

The VDRL test is a nontreponemal test for the detection of sexually transmitted disease syphilis. Nontreponemal tests are non-specific tests. These tests can sometimes yield a false-positive result. The VDRL test is used to diagnose syphilis infection for those who engage in unsafe sexual activities that put them at risk.

Treponema pallidum (T. pallidum) is the bacteria that causes syphilis infection. T. pallidum is a causative agent of syphilis infection, which is sexually transmitted. Syphilis affects the area around the genitals, lips, inner side of the mouth or anus of both men and women.

Syphilis can be transmitted from mother to baby during pregnancy. In addition, syphilis can spread to all parts of the body after entering into the bloodstream. Syphilis, if left untreated, can affect vital organs like the heart, brain, nervous system and eyes.

Syphilis is a gonorrhoeal disease. There are four stages of syphilis infection:

Primary

Primary syphilis infection occurs after three weeks to three months of contamination. It begins with a small red lesion called a Chancre. Chance is a highly contagious lesion.

The VDRL results can be false negative in this phase.

Secondary

Secondary syphilis infection presents with symptoms of fever, headache, swollen lymph nodes and joint pain. These symptoms slowly fade away with or without treatment. Without treatment, syphilis infection grows to the next phase. The VDRL test will be reactive in this stage.

Latent

The third phase is known as the latent phase because it is the hidden phase. In this phase, there will not be any perceptible signs and symptoms. In this phase, the bacterial infection progresses to the tertiary phase.

Tertiary

The tertiary syphilis phase is the last phase of infection. Tertiary syphilis infection becomes noticeable years after the latent syphilis phase. The tertiary syphilis phase can be life-threatening. The symptoms of the tertiary syphilis phase are blindness, deafness and neurological symptoms.

The human body produces antibodies in response to T. pallidum. These antibodies are proteins that destroy the invading bacteria. Therefore, a blood or CSF sample is needed to perform a VDRL test.

VDRL is a type of slide flocculation test. In this test, cardiolipin is used as an antigen to detect antibodies in the serum. Alcohol-extract bovine heart muscle is a cardiolipin antigen. Lecithin and cholesterol are added to Cardiolipin antigen. When there are antibodies in the serum, cardiolipin reacts with them to form flocculation.

Within 2-3 weeks of treponemal infection due to tissue damage, autoantibodies are formed. Cardiolipin and the autoantibodies react with each other and VDRL results are generated.

The VDRL test does not detect bacteria that cause syphilis infection. Instead, it detects antibodies produced in response to T. pallidum bacteria.

Testing these antibodies helps doctors detect syphilis infection. Even without any symptoms, the VDRL test yields accurate results. VDRL test checks for proteins that fight infection. Hence VDRL test can be used irrespective of symptoms.

The VDRL chart reveals the number of antibodies in blood or CSF samples. The VDRL test does not react with the T. pallidum bacteria. The doctor asks for a CSF VDRL test result when he suspects an advanced stage of syphilis infection. If syphilis infection is diagnosed and treated in time, complications and damage to organs are prevented.

Blood sample

In the majority of the cases, a simple blood sample is sufficient for a VDRL test. Therefore, blood samples from veins are collected for the VDRL test.

CSF (cerebrospinal fluid) sample

In advanced cases, the VDRL test is done with a sample of CSF. CSF collection is done with a lumbar puncture(spinal tap).

Syphilis, Gonorrhoea, Neurosyphilis

The VDRL values reveal the presence or absence of antibodies to syphilis infection. In addition, it detects proteins that defend and destroy invading T. Pallidum bacteria.

TheVDRL is prescribed for the following conditions:

• As a part of a routine screening test in pregnancy.
• In people who have multiple sex partners.
• In people who get engaged in unprotected sexual activity.
• In men and women who practise homosexuality.
• In people who have undergone treatment for gonorrhoea.
• In case the person has signs and symptoms of a sexually transmitted disease:
• The appearance of chancre (a round, red sore) on genitals.
• Wart-like lesions in vagina, anus, male genitals and mouth.
• Red rashes on any parts of the body.
• The appearance of red and firm sore lesions on any part of the body. 
• Swollen lymph nodes
• Fever
• Muscle aches
• Sore throat
• Hair Fall in patches
• Unexplained weight loss
• Soft tissue swelling

The VDRL test is repeated based on the symptoms and as per the doctor’s advice. In addition, VDRL values are usually repeated based on the prognosis of gonorrhoea and syphilis infection. The doctor will advise repetition in those:

• Who have symptoms of syphilis infection or gonorrhoea
• Who has a recent history of syphilis treatment
• Who are currently under treatment for another sexually transmitted disease
• Who have a history of some other sexually transmitted disease

Before the Test

Typically, preparation for a VDRL test does not necessitate any special arrangements. If you are undergoing this test in conjunction with another one, your healthcare provider might advise you to abstain from consuming certain food items. It is always recommended to consult with your doctor prior to the test for optimal results.

During the Test

The blood sample will be drawn from a vein in your arm. Here’s what you can expect during the test:

• The area where the needle will be inserted will be cleansed with an antiseptic.
• A tourniquet band will be fastened around your arm to enhance the visibility of the veins.
• A needle will be inserted into the vein to draw the blood. This process is likely to take a few seconds and during this time, you might feel a brief pinch.
• The blood will be collected in a vial or a small test tube labelled with your details.

After the Test

Once the blood has been collected:

• A bandage will be applied to the puncture site to halt the bleeding.
• Mild bruising is common. But if you're feeling lightheaded, you may be advised to sit for a few minutes.
• Contact your healthcare provider if you experience bleeding, pain, or rashes at the puncture site.

The VDRL test detects antibodies to syphilis infection caused by the bacteria T. palladium.

The normal values and reference ranges of the test may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

• VDRL negative: A VDRL negative test means you are healthy. It means blood samples do not contain any antibodies to T. palladium.
• VDRL positive: A VDRL positive test means the sample contains antibodies of syphilis infection.

The ability of the VDRL test to detect antibodies depends on the stage of syphilis infection. VDRL test may show false-negative results in the primary phase of syphilis infection. VDRL chart results are more accurate in the secondary and latent phases of syphilis infection.

It is always advisable to confirm with the FTA-ABS test for the final diagnosis of syphilis infection.

VDRL CSF test

• VDRL negative: A negative CSF test does not rule out syphilis infection in the nervous system. The VDRL normal range is observed in VDRL negative.
• VDRL positive: In abnormal VDRL range values, the doctors will perform a confirmatory test for T. pallidum antibodies. Neurosyphilis is confirmed, if these test results are positive. Neurosyphilis is a fatal condition involving the brain.

Some conditions may cause false-positive results, include:

• HIV/AIDS
• Lyme disease
• Certain types of pneumonia
• Malaria
• Tuberculosis
• Systemic lupus erythematosus
• Used IV drug
• Recent history of blood transfusion

The cost of a VDRL(Venereal Disease Research Laboratory) Test varies depending on the city and the lab. In general, a VDRL test price ranges between INR 129 and INR 439. Here is a breakdown of the average cost of a VDRL test in some major cities in India: