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 false-positive results. 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 bacterium that causes syphilis infection. This bacterium is sexually transmitted and infects both men and women. 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 the bloodstream. Syphilis, if left untreated, can affect vital organs like the heart, brain, nervous system and eyes.

Syphilis is a gonorrheal 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 negatives 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, the 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 the 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. It detects the presence of antibodies formed to fight the 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.

Other Names of VDRL Test

• Syphilis - VDRL
• Venereal disease research laboratory test

What does the VDRL test detect or measure?

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.

To whom is the VDRL test prescribed?

The VDRL 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 the 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

A simple blood sample is sufficient for a VDRL test. Therefore, blood samples from veins are collected for the VDRL test.

Test Preparation

The VDRL procedure does not require any special preparation. A sample of blood is obtained from the vein.

Test inclusions: What are the parameters included?

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

Syphilis, Gonorrhoea, Neurosyphilis

The normal values, parameters, 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.

Some conditions that 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