Anti-cardiolipin antibodies are the most common form of anti-phospholipid autoantibodies often directed against cardiolipin. Cardiolipins are lipid molecules found in cell membranes and platelets. They play an important role in the blood clotting process; therefore, antibodies directed against cardiolipin increases an affected person’s risk of developing recurrent inappropriate blood clots in both arteries and veins. This test is involved in the investigation of thrombosis in the young, recurrent abortion, or persistent thrombopenia. It may also be ordered to help determine the cause of a positive (VDRL) test for syphilis, since the reagents used to test for syphilis contain phospholipids and can cause a false positive result in patients with cardiolipin antibodies. IgG antibodies are more specific than IgM. ELEVATED levels may be associated with thrombocytopenia, recurrent miscarriages, pre-mature labor, and Systemic Lupus Erythematosus (SLE)