How Is Antiphospholipid Antibody Syndrome Diagnosed?

Your doctor will diagnose antiphospholipid antibody syndrome (APS) based on your medical history and the results from blood tests.

Specialists Involved

People who have APS often are treated by a hematologist (a blood disease specialist). You may have APS and another autoimmune disorder, such as lupus. If so, you also may be treated by a doctor who specializes in that disorder.

Many autoimmune disorders that occur with APS also affect the joints, bones, or muscles. Rheumatologists specialize in treating these types of disorders.

Medical History

Some people have APS antibodies, but don’t ever have signs or symptoms of the disorder. The presence of APS antibodies, by itself, doesn’t mean that you have APS.

To be diagnosed with APS, you must have APS antibodies and a history of health problems related to the disorder. These health problems may include stroke, heart attack, kidney damage, deep vein thrombosis (throm-BO-sis), pulmonary embolism (PULL-mun-ary EM-bo-lizm), or pregnancy-related problems.

Pregnancy-related problems may include multiple miscarriages, a miscarriage late in pregnancy, or a premature birth due to eclampsia. (Eclampsia, which follows preeclampsia, is a serious condition that causes seizures in pregnant women.)

Blood Tests

Your doctor can use blood tests to confirm a diagnosis of APS. These tests check your blood for any of the three APS antibodies: anticardiolipin, B2 glycoprotein I, and lupus anticoagulant.

The term "anticoagulant" refers to a substance that prevents blood clotting. It may seem odd that one of the APS antibodies is called lupus anticoagulant. This is because the antibody slows clotting in lab tests. However, in the human body, it increases the risk for blood clots.

To test for the APS antibodies, a small amount of blood is taken from your body. It's often drawn from a vein in your arm using a small needle. The procedure usually is quick and easy, but it may cause some short-term discomfort, such as a slight bruise.

You may need a second blood test to confirm positive results. This is because a single positive test can result from a short-term infection. The second blood test often is done 12 weeks or more after the first one.

Some healthy people may test positive for APS antibodies but have no signs or symptoms of the disorder. The presence of the APS antibodies, by itself, doesn't mean that you have APS.