Test, VDRL: A blood test for syphilis (VDRL stands for Venereal Disease Research Laboratory) that detects an antibody that is present in the bloodstream when a patient has syphilis.

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

See also syphilis; syphilis test, RPR.