The Anti-Phospholipid Antibody, IgM test detects IgM antibodies against phospholipids, which are fats present in cell membranes. Elevated IgM levels can be associated with antiphospholipid syndrome (APS), an autoimmune disorder that increases the risk of blood clots, recurrent miscarriages, and other thrombotic events. While IgG antibodies are more commonly tested, IgM antibodies may also indicate APS, particularly in cases of acute or active disease. A blood sample is required for this test, helping to assess the risk of clotting and guide appropriate management.