VDRL-RPR (Syphilis Screening)

What is VDRL (RPR)?

VDRL and RPR are two similar tests used in screening for syphilis. Rather than detecting the bacterium itself, these tests look for antibodies formed against lipid substances such as cardiolipin, which are released from cells damaged during the infection. For this reason they are called non-treponemal tests and are not specific to the bacterium. Because they are easy to perform, they have been widely used in screening programs for many years.

The level of these antibodies follows disease activity; after effective treatment it falls over time and becomes negative in most people. Positive samples are tested in serial dilutions, and the result is reported as a titer, that is, the highest dilution at which the antibody can still be detected. This feature makes the test valuable both in screening and in monitoring the response to treatment. Although VDRL and RPR work on the same principle, their titers cannot be used interchangeably.

When is the VDRL (RPR) test ordered?

VDRL-RPR is ordered for syphilis screening in people without symptoms and to monitor the effect of treatment in people who have been diagnosed. Every reactive result is confirmed with a test specific to the bacterium, such as TPHA. Because syphilis symptoms are often painless and can disappear on their own, the fading of symptoms does not mean that the infection has ended. In people diagnosed with syphilis, testing for other sexually transmitted infections, above all HIV, is also recommended.

• Routine syphilis screening in pregnancy
• A painless sore, rash or enlarged lymph nodes in the genital area
• A partner diagnosed with syphilis or another sexually transmitted infection
• Follow-up at set intervals after syphilis treatment
• Comprehensive sexual health check

How should I prepare for the VDRL (RPR) test?

You do not need to fast before VDRL-RPR. Pregnancy, autoimmune diseases such as lupus, recent infections with fever and vaccinations can cause false-positive results, so share this information with your doctor. If you are being monitored after treatment, it is recommended that you have your follow-up tests done at the same laboratory and with the same method if possible, so that the titers can be compared.

A single tube of blood drawn from the arm is enough to obtain serum. During follow-up after treatment, repeat blood draws can be planned more easily with a Curavita nurse coming to your home or workplace. There may be a slight ache after the blood draw, which passes quickly.

What does the VDRL (RPR) result mean?

A negative or non-reactive result usually suggests that there is no active syphilis. However, the test may be negative in the very early stage of infection or in late-stage syphilis that has gone untreated for a long time. If there has been a recent risky contact, your doctor may recommend repeating the test a few weeks later. In a situation known as the prozone effect, seen with very high antibody levels, the result can also be falsely read as negative, so the laboratory dilutes the sample and retests it when necessary.

A reactive result suggests the possibility of syphilis; however, because false positives can occur in situations such as pregnancy, autoimmune diseases and some viral infections, it must always be confirmed with a test such as TPHA. After treatment, a marked fall in the titer indicates a response to treatment, while a rise is evaluated for reinfection or an inadequate response. In some people, a low titer may persist for a long time even after successful treatment. Although reference ranges can generally vary by laboratory, age and sex, this test is reported as negative or reactive; the laboratory's reference is stated on this page. It is your doctor's role to interpret the result of this test by considering it together with your complaints and complementary test findings.