Cardiolipin Antibodies
- Also Known As:
- Anticardiolipin Antibodies
- aCL Antibody
- Formal Name:
- Cardiolipin Antibodies (IgG
- IgM
- and IgA)

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At a Glance
Why Get Tested?
To help investigate inappropriate blood clot formation, to help determine the cause of recurrent miscarriage, or as part of an evaluation for antiphospholipid syndrome or sometimes other autoimmune diseases
When To Get Tested?
When you have had one or more unexplained blood clots (thrombotic episodes) in a vein or artery; when you have had recurrent miscarriages, especially in the second and third trimesters; when you have symptoms consistent with an autoimmune disease
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
You may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Testing.com. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.
Testing.com is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.
The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.
If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.
Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.
While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”
For more information, please read the article Reference Ranges and What They Mean.
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) in veins and arteries, such as the deep veins of the legs (DVT) or the lungs (pulmonary embolism, PE). 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 pre-eclampsia.
Cardiolipin antibodies are the most common antiphospholipid antibody, a group of autoantibodies associated with excessive clotting and autoimmune diseases, such as lupus. They are frequently detected with other antiphospholipid antibodies, such as lupus anticoagulant and anti-beta-2 glycoprotein 1. 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 or secondary. Primary APS is not necessarily associated with a related autoimmune disorder, while secondary APS is associated with an autoimmune disorder.
Common Questions
Related Content
On This Site
Tests: Antiphospholipid Antibodies; Beta-2 Glycoprotein 1 Antibodies; Autoantibodies; Lupus Anticoagulant Testing
Elsewhere On The Web
The Lupus Foundation of America: Antiphospholipid Antibody Syndrome
March of Dimes: Pregnancy Complications, Thrombophilias
APS Foundation of America
National Human Genome Research Institute: Learning About Antiphospholipid Syndrome (APS)
View Sources
Sources Used in Current Review
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Moake, J. (Revised 2016 September) Antiphospholipid antibody syndrome. Merck Manual Professional Version. Available online at http://www.merckmanuals.com/professional/hematology-and-oncology/thrombotic-disorders/antiphospholipid-antibody-syndrome-aps. Accessed 12/27/2016.
(Updated 2016 December). Antiphospholipid syndrome – APS. ARUP. Available online at http://www.arupconsult.com/Topics/APS.html?client_ID=LTD. Accessed 12/27/2016.
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(May 17, 2012) National Heart, Lung and Blood Institute. How Is Antiphospholipid Antibody Syndrome Diagnosed? Available online at https://www.nhlbi.nih.gov/health/health-topics/topics/aps/diagnosis. Accessed January 2017.
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(© 2004). Cardiolipin Antibodies, IgG and IgM. ARUP’s Guide to Clinical Laboratory Testing. Available online at http://www.arup-lab.com/guides/clt/tests/clt_a133.jsp#1059158.
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