VDRL

VDRL is a blood test that checks for syphilis, a sexually transmitted infection caused by the bacterium Treponema pallidum. It shows signs of infection and is also used to monitor treatment success. A positive result is always confirmed with another test, and syphilis is successfully treated with antibiotics.

Who is this test for

• people who have had unprotected sex with a new or casual partner;
• if you have a painless sore on the genitals, in the mouth or around the anus, or a rash, particularly on the palms and soles;
• if your partner has been diagnosed with syphilis;
• pregnant women, for whom syphilis testing is part of antenatal care;
• people being tested for other sexually transmitted infections, such as HIV;
• after syphilis treatment, to monitor treatment success.

What the test reveals

VDRL does not detect the bacterium itself. It shows antibodies produced by the body during infection that are directed not specifically against treponema, but against cardiolipin, a substance from damaged cells. These tests are therefore called non-treponemal. The level of these antibodies follows disease activity: it rises during infection and falls after successful treatment, often to a negative result.

Because the test is not completely specific, a positive VDRL is confirmed with a treponemal test, such as the TPHA test, which looks for antibodies directed against the bacterium.

The test and preparation

The sample is blood from a vein, and collection takes a few minutes. You do not need to fast, and no special preparation is required. Antibodies develop only several weeks after infection, so a test performed shortly after a risky contact may be negative. Your doctor will tell you whether it needs to be repeated.

What your results mean

• A negative result means that antibodies were not found. If little time has passed since the risky contact or you have symptoms, the test is repeated; if there is a sore, the doctor may also request PCR detection of Treponema pallidum.
• A positive VDRL suggests syphilis but may also be false-positive, for example during pregnancy, in autoimmune diseases, some viral infections or older age. It is therefore always confirmed with a treponemal test.
• A positive VDRL and a positive treponemal test support syphilis, either current or previously treated. A doctor decides on treatment, and the partner should also be tested.
• Follow-up after treatment: after successful treatment, VDRL antibodies fall over time, often to a negative result. The antibody titre (level) is not part of this report, so the doctor determines the follow-up schedule and method. Treponemal tests remain positive for life in most people.

The doctor interprets the report alongside symptoms and previous results.

How to arrange testing

You can come for blood collection without an appointment or referral at one of our branches throughout Croatia (listed on the Contactpage). Prices for all tests and panels are listed in the price list. VDRL is most often performed alongside the TPHA test; read about testing for other sexually transmitted infections on the Sexually transmitted infection testing.

Frequently asked questions

What is the difference between the VDRL and TPHA tests?

VDRL shows non-specific antibodies and tracks disease activity well. TPHA looks for antibodies against the bacterium itself, confirms infection and remains positive in most people even after cure.

How soon after a risky sexual contact can I take the test?

Antibodies develop only several weeks after infection. If the test was performed earlier, the doctor usually advises repeating it around three months after the risky contact.

Can VDRL be positive even if I do not have syphilis?

Yes. A false-positive result occurs during pregnancy, in autoimmune diseases, some infections and older age. A positive VDRL is therefore always confirmed with a treponemal test.

Can syphilis be treated?

Yes. Syphilis is successfully treated with antibiotics, most often penicillin, prescribed by a doctor. Untreated, it can persist for years without symptoms and damage the heart, nerves and other organs, and it can be passed to the baby during pregnancy.