DefinitionThe VDRL test is a screening test for syphilis. It measures substances, called antibodies, that can be produced in response to Treponema pallidum, the bacteria that causes syphilis.The test is similar to the newer rapid plasma reagin (RPR) test.Alternative NamesVenereal disease research laboratory testHow the test is performedThe test is usually performed on blood. The VDRL test can be performed on spinal fluid if syphilis (neurosyphilis) may be present in individual's brain.This article discusses the blood test.Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell