Test Details: Lupus anticoagulants (LA) are autoantibodies produced by the immune system that mistakenly attack certain components of the body’s own cells. They specifically target phospholipids as well as the proteins associated with phospholipids that are found in the outer-most layer of cells (cell membranes). These autoantibodies interfere with the blood clotting process in a way that is not fully understood and increase a person’s risk of developing a blood clot. This test helps to investigate the cause of a blood clot (thrombotic episode) and to evaluate a prolonged partial thromboplastin time (PTT).