RPR test

Rapid plasma reagin, a blood test for syphilis that looks for an antibody that is present in the bloodstream when a patient has syphilis.

A negative (nonreactive) RPR is compatible with a person not having syphilis, but in the early stages of the disease, the RPR often gives false negative results. Conversely, a false positive RPR can be encountered in infectious mononucleosis, lupus, antiphospholipid antibody syndrome, hepatitis A, leprosy, malaria and, occasionally, pregnancy.