Anti Phospholipid Antibodies IgA test is a test carried out on a blood sample to determine the measure of immunoglobulin A(IgA), a common antibody, in your blood. In actuality, antibodies defend the body against infections. But Anti Phospholipid Antibodies like IgA attack phospholipids, which is a type of fat found in blood cells and cell membranes, and damage those cells. This results in blood clots in the arteries and veins, excess of which is harmful. IgA particularly, is found in the respiratory passages, gastrointestinal tract, tears and saliva and its high concentration may result in allergic reactions and immune system disorders and disorders of the kidneys, lungs and intestines