Lupus and your body

Can I be tested for antiphospholipid antibodies?

Dr. Michelle Petri is the Director of the Hopkins Lupus Cohort, a longitudinal study of morbidity and mortality in systemic lupus erythematosus, and Co-Director of the Hopkins Lupus Pregnancy Center.

See all of Michelle Petri, MD, MPH's answers.

Specialized blood tests which measure blood clotting (coagulation tests) are used to find lupus anticoagulant. The activated partial thromboplastin time (aPTT) is a widely available blood clotting test that is often used. If the aPTT is normal, more sensitive coagulation tests should be done, which include modified Russell viper venom time (RVVT), platelet neutralization procedure (PNP), and kaolin clotting time (KCT). If the number of seconds that it takes the blood to clot is prolonged, the physician will suspect that lupus anticoagulant is present. This can be confusing, because even though the blood takes longer to clot in the test tube, the blood actually clots more easily in the person’s body.

Anticardiolipin antibody and anti-β2 glycoprotein I are measured in an ELISA test. There are several classes of anticardiolipin antibody—IgG, IgM, and IgA. It is possible to test for all of these antibody classes at once, or the physician may wish to test for each one separately. The IgG and IgA types of anticardiolipin antibody and anti-beta2 glycoprotein are most often associated with thrombotic complications. Some lupus patients with very high IgM anticardiolipin antibody have a problem called "hemolytic anemia," in which their immune system attacks their red blood cells.

There are no current recommendations on the timing of repeat tests for these antibodies. Certainly the antiphospholipid antibodies should be checked in people who have had thrombotic problems, miscarriages, or low platelet counts.

Medically reviewed on July 26, 2013