The Anti-Cardiolipin Antibody IgA test measures the presence of IgA antibodies against cardiolipin, a type of fat molecule found in cell membranes. Elevated levels of these antibodies may be associated with autoimmune conditions, particularly antiphospholipid syndrome (APS), which increases the risk of blood clots, recurrent miscarriages, or certain neurological conditions. This test is typically used to diagnose APS and monitor patients with autoimmune disorders. A blood sample is required for this test.