Automated Immunoassays for Syphilis Antibodies – Negative, Positive

  • If the RPR is also positive (especially at >1:8) and there is no history of treatment for syphilis, a diagnosis of syphilis is made and the patient should receive treatment.
  • Most people become negative for RPR with adequate treatment, though some patients who present with later stage disease may maintain a low titer RPR (<1:8) for life despite adequate treatment. This is the serofast state.

Antibody tests:

A negative blood test means that it is likely that no infection is present. However, a negative screening test means only that there is no evidence of disease at the time of the test. Antibodies may not be detected for several weeks after exposure to the bacteria.

If a person knows he or she has been exposed, or if suspicion of infection remains high, then repeat testing at a later date may be required.

It is also important for those who are at increased risk of syphilis infection to have screening tests performed regularly to check for possible infection.

A positive RPR or VDRL screen must be followed by a specific treponemal antibody test (e.g., FTA-ABS, TP-PA).

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.