The VDRL (Venereal Disease Research Laboratory) is a non-specific cardiolipin microflocculation test for the detection of (auto) antibodies against phospholipids of the mitochondrial membrane (cardiolipin). Cardiolipin is found in Treponema pallidium, also in other microorganisms. Furthermore also in various other microorganisms. Due to the cross-reaction with phospholipids (cardiolipin) (see phospholipid antibodies). If the antibodies are present, the precipitation (flocculation reaction) of cardiolipin occurs. False positive results are found in autoimmune diseases (phospholipid antibody syndrome, SLE), acute or chronic infections (leprosy), neoplasms.
Uses: The quantification (titration) of VDRL is a good parameter for the need for treatment of syphilis. In this respect, this test still has a clinical use (see also Syphilisserology).
VDRL becomes positive 4-6 weeks (!) after infection (titer >1:4). Test is therefore still negative when the primary effect occurs. The test becomes negative again months after successful therapy.