The VDRL test detects the presence of syphilis. The test is indicated for individuals with symptoms or risk of exposure to syphilis or other STDs. Syphilis is a mandatory reporting disease. The VDRL test detects a constituent associated with the presence of the bacteria that causes syphilis (Treponema pallidum). In an undiagnosed individual, a positive VDRL test must be confirmed at the Laboratoire de santé publique du Québec (LSPQ) by a technique that detects the bacterium itself. Syphilis can be detected approximately ten days after infection. The window (period during which detection is possible) ends twelve weeks after exposure.
A negative VDRL test result indicates the absence of syphilis or the presence of syphilis in a dormant stage. If suspected, the test should be repeated three months after the presumed contact. A positive VDRL test confirmed by the LSPQ indicates the presence of syphilis, which will need to be staged based on the clinical presentation (primary or secondary infectious, latent, etc.). If a positive VDRL test is not confirmed by the LSPQ, there is no infection unless it is in the incubation period. A new test is indicated two to four weeks after the first.