At a glance
Also known as
Anticardiolipin antibodies; ACL antibody; ACL IgA; ACL IgG; ACL IgM
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
When to get tested?
When you have had one or more unexplained venous or arterial ; when you have had recurrent miscarriages, especially in the 2nd and 3rd trimesters
A blood sample drawn from a vein in your arm
What is being tested?
These tests detect the presence of three classes (, , and/or ) of cardiolipin antibodies. Produced by the immune system in response to a perceived threat, these proteins are the most common form of antiphospholipid antibodies. They are acquired autoantibodies that can affect the body's ability to regulate blood clotting in a way that is not well understood.
Cardiolipins, and other related , are lipid molecules normally found in cell membranes and platelets. They play an important role in the blood clotting process. When antibodies are produced against cardiolipins, they increase an affected patient's risk of developing recurrent inappropriate blood clots (thrombi) in both arteries and veins. Cardiolipin antibodies are also associated with , recurrent miscarriages (especially in the 2nd and 3rd trimester), and with premature labour and .
Cardiolipin antibodies are frequently seen with autoimmune disorders, such as systemic lupus erythematosus (SLE), and with other antiphospholipid antibodies, such as lupus anticoagulant. They may also be seen temporarily in patients with infections, HIV/AIDS, some cancers, with drug treatments (such as phenytoin, penicillin, and procainamide), and in the elderly.
They may occur in low , which has no known clinical significance.
When a patient has excessive blood clot formation, recurrent miscarriages, thrombocytopenia, cardiolipin antibodies, and/or another antiphospholipid antibody, they may be diagnosed with antiphospholipid syndrome (APS). APS can be primary with no underlying autoimmune disorder (50%) or secondary, existing with a diagnosed autoimmune disorder, most commonly SLE.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
If I have anticardiolipin antibodies, will I definitely develop blood clots?
Not necessarily. The cardiolipin antibodies represent a risk factor, but they cannot predict whether an individual person will have recurrent blood clots or other associated complications. And, if a person does have blood clots, the presence of the antibodies cannot predict their frequency or severity. Compared to the presence of lupus anticoagulant, cardiolipin antibodies are lesser risk factors for thrombosis.
Should I tell a new doctor that I have anticardiolipin antibodies?
Yes, this is an important part of your medical history. Your doctor needs this information even if you are so that they can tailor any procedures or medical treatment plans around this risk factor.