Antiphospholipid syndrome (APS) is an autoimmune disorder, meaning that the body's immune system makes proteins known as antibodies that mistakenly attack its own cells or tissues. The syndrome is associated with risk of inappropriate blood clot formation, so it is considered an excessive clotting disorder (thrombophilia).
Antibodies normally defend the body against infections. But in APS, antibodies attack the lipid-proteins found in the outermost layer of cells (cell membranes) and platelets. These autoantibodies interfere with the blood clotting process in a way that is not fully understood. APS is associated with blood clots (thrombotic episodes), a low number of platelets (thrombocytopenia), and with pregnancy complications such as pre-eclampsia and recurrent miscarriages.
Lupus anticoagulant testing
Beta2 glycoprotein I (β2GP1) antibodies