Does this test have other names?

Cardiolipin antibodies (IgG, IgM, IgA), anticardiolipin, aCL antibody

What is this test?

A cardiolipin antibodies test looks for a certain kind of antibody in your blood. An antibody is a substance in your blood that helps fight off infection. The antibodies attack cardiolipins by mistake. Cardiolipin is a phospholipid, or a kind of fat in the blood that is important for blood clotting. When the antibodies attack cardiolipin, blood clots can occur. Platelets, blood cells that help blood to clot, also get used up, leading to problems with bleeding. The levels of these antibodies are often high in people with abnormal blood clotting, autoimmune diseases like systemic lupus erythematosus (SLE), or repeated miscarriages. 

Why do I need this test?

You may need this test if you often have abnormal blood clotting or abnormal bleeding. If you have had frequent miscarriages, the test might help healthcare providers figure out why. Also, people with some autoimmune diseases, such as SLE, have cardiolipin antibodies in their blood. This test may be used to help diagnose this disease. When high levels of cardiolipin antibodies are found in people with these or other issues, it is known as cardiolipin antibody syndrome. This test helps diagnose this condition. 

What other tests might I have along with this test?

The cardiolipin antibodies test is usually just 1 of many tests that may be done to check why you are having your symptoms. The tests you get will depend on what your healthcare provider is looking for. For example, if your healthcare provider thinks you have SLE, you will probably need other blood tests. You may also need imaging tests and tissue biopsies. 

These other tests may include:

• Complete blood cell count

• Partial thromboplastin time and activated prothromboplastin time. These tests see how your blood clots.

• Antinuclear antibody test. These antibodies are found in people with lupus.

• Antiphospholipid antibody test. These antibodies are found in people with abnormal blood clots.

• Ultrasound to look for clots in your arteries or veins

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

The results of a cardiolipin antibody test are easy to understand. If you're negative for cardiolipin antibodies, that is normal. If you're positive, you might have cardiolipin antibody syndrome. You will probably be retested to see if the antibody stays in your blood. You may need to wait as long as 12 weeks between each test period.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. 

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore. 

What might affect my test results?

Although cardiolipin antibodies are commonly related to SLE, a positive test for them doesn't mean you have it. Other tests will be needed to confirm the diagnosis. When you have problems related to blood clotting, miscarriages, or other issues, this test result can help healthcare providers figure out the best way to treat your condition.

How do I get ready for this test?

You don't need to prepare for this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any street drugs you may use.