Venereal Disease Research Laboratory (VDRL) test is a blood examination used to detect syphilis. A VDRL test result that is negative, or "nonreactive," typically suggests that a person does not have syphilis. Nevertheless, it's possible to have syphilis and still receive a negative VDRL result, especially in the disease's early stages, leading to what is known as a false negative. Conversely, the VDRL can show a positive result even when syphilis is not present. Such false positives may occur in cases of infections, the antiphospholipid antibody syndrome, certain autoimmune diseases, and sometimes during pregnancy. The Rapid Plasma Reagin (RPR) test functions similarly to the VDRL, identifying antibodies in the blood indicative of syphilis. However, early infections may result in a false negative, and the RPR can also produce false positives.
