VDRL false positive test: What are the causes of this?

Last updated: August 15, 2026

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VDRL test or Venereal Disease Research Laboratory test is a very common syphilis screening test. The problem will be occurred when VDRL turn positive without any suspicious of syphilis infection, we called this incident “Biological false positive” or BFP reaction. Today we will discuss on this BFP phenomenon.

BFP phenomenon has been reported around 1-2% of an incidence. BFP usually showing out in a low dilutions (<1:8). Here are the possibilities of BFP phenomenon.

Causes of VDRL False positive phenomenon

1. Laboratory error from unwell-trained technicians
2. Autoimmune diseases – SLE or Rheumatoid arthritis
3. Febrile illness – Malaria, Tuberculosis, Filariasis
4. Pregnancy
5. Recent immunization
6. Aging
7. Drug addiction
8. Liver disease
9. Malignancy

Once BFP phenomenon is suspected, a careful history taking and proper investigation must be done. It would be recommended to retest VDRL again at 10 weeks — most cases will turn nonreactive at that time. Any questions, you can discuss with your trusted physicians, or it would be my honor if you can text me. Take care!

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Frequently Asked Questions

Q1: What does a VDRL false positive result mean?

A VDRL false positive result means the test shows a reactive result without the person actually having a syphilis infection. This is known as a Biological False Positive (BFP) reaction, which occurs in approximately 1-2% of cases. BFP results typically appear at low dilution levels (less than 1:8) and require further investigation to identify the true underlying cause.

Q2: What conditions can cause a VDRL false positive?

Common causes of VDRL false positive include autoimmune diseases such as SLE and rheumatoid arthritis, febrile illnesses such as malaria and tuberculosis, pregnancy, recent vaccinations, aging, drug addiction, liver disease, and malignancy. Laboratory error from untrained technicians is also an important consideration when a false positive is suspected.

Q3: How can I confirm whether my VDRL positive is a true or false positive?

When a false positive is suspected, a confirmatory treponemal test such as TPHA or FTA-ABS should be performed. If the confirmatory test is negative while VDRL is positive, a BFP reaction is highly likely. Retesting VDRL at 10 weeks is also recommended, as most BFP cases will revert to non-reactive within this timeframe.

Q4: Should I be worried if my VDRL test comes back positive?

A positive VDRL result should not cause immediate panic, as false positives do occur. However, it should always be evaluated by a physician rather than ignored. A thorough clinical history, physical examination, and confirmatory testing are necessary to determine whether the result represents true syphilis infection or a biological false positive.

Q5: Can pregnancy cause a false positive VDRL?

Yes. Pregnancy is one of the recognized causes of a VDRL biological false positive reaction. Pregnant women who receive a positive VDRL result should be evaluated with a confirmatory treponemal test to differentiate a true syphilis infection from a pregnancy-related false positive, as appropriate treatment during pregnancy is critical for fetal health.

If you have received a positive VDRL result and are unsure how to interpret it, Dr. Soarawee Weerasopone offers specialist consultations in sexual health at Bangkok Hospital Headquarters. Book a Consultation.

Disclaimer: This content is written and reviewed by Dr. Soarawee Weerasopone, a board-certified urologist at Bangkok Hospital Headquarters. It is intended for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any medical treatment.