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Cardiolipin Antibodies

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Also known as: Anticardiolipin Antibodies; aCL Antibody
Formal name: Cardiolipin Antibodies (IgG, IgM, and IgA)

The Test Sample

What is being tested?

Cardiolipin antibodies are autoantibodies produced by the immune system that mistakenly target the body's own cardiolipins, substances found in the outermost layer of cells (cell membranes) and platelets. These autoantibodies can affect the body's ability to regulate blood clotting in a way that is not well understood. This test detects the presence of cardiolipin antibodies in the blood.

Cardiolipins, and other related phospholipids, are lipid molecules that play an important role in the blood clotting process. Cardiolipin antibodies target cardiolipins and are associated with an increased risk of developing recurrent inappropriate blood clots (thrombi). They may also be associated with a low platelet count (thrombocytopenia), recurrent miscarriages (especially in the second and third trimester), and with premature labor and preeclampsia.

Cardiolipin antibodies are the most common antiphospholipid antibody, a group of autoantibodies associated with excessive clotting and autoimmune diseases, such as Systemic Lupus Erythematosus (SLE). They are frequently detected with other antiphospholid antibodies, such as lupus anticoagulant and anti-beta2 glycoprotein I. They may also be detected temporarily in people with acute infections, HIV/AIDS, some cancers, with drug treatments (such as phenytoin, penicillin, and procainamide), and in the elderly.

When an individual has inappropriate blood clot formation, recurrent miscarriages, cardiolipin antibodies, and/or another antiphospholipid antibody, the person may be diagnosed with Antiphospholipid Syndrome (APS). APS can be primary, that is, not necessarily associated with a secondary or related autoimmune disorder.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.