myUpchar प्लस+ के साथ पूरेे परिवार के हेल्थ खर्च पर भारी बचत

What is a Cardiolipin antibodies (ACL) test?

An ACL test evaluates the presence of cardiolipin antibodies in blood. These antibodies are usually present in high numbers in people with severe clotting and autoimmune diseases. They damage the cardiolipins present on the cell membrane of blood vessels (arteries and veins) and activate the blood clotting process, which results in the development of blood clots in vessels. These blood clots (thrombi) cause deep vein thrombosis (DVT), pulmonary embolism, recurrent miscarriages and low platelet levels (thrombocytopenia)

  1. Why is an ACL test performed?
  2. How do you prepare for an ACL test?
  3. How is an ACL test performed?
  4. What do ACL test results indicate?

Cardiolipin antibodies are evaluated in people who experience excessive clotting. The signs and symptoms of thrombosis depend on the site and size of the blood clot. The commonest diseases occurring due to these clots are DVT, pulmonary embolism and recurrent miscarriages.

Symptoms of DVT include:

  • Pain, tenderness and swelling of the affected leg (usually calf)
  • Heaviness in the affected leg
  • Skin in the area of the clot feels warm
  • Reddish discolouration of the affected leg (below the knee)

Symptoms of pulmonary embolism include:

ACL test is usually performed along with other phospholipid antibodies, such as lupus anticoagulants and anti-beta-2 glycoprotein 1 and activated partial thromboplastin time (aPTT)

Usually, no special precautions or preparations are required for evaluating cardiolipin antibodies.

It is a simple test that takes less than five minutes. An experienced laboratory specialist will collect a blood sample from a vein in your arm by inserting a small needle. A small quantity of blood will be withdrawn into a sterile vial or test tube. You may feel a momentary pricking pain as the needle goes into the vein and there is a minimal risk of pain, light-headedness and bruising at the site of injection with the test.
However, at most times, these symptoms disappear quickly. Rarely, an infection may occur at the site of withdrawal of blood.

Normal results: Absence of cardiolipin antibodies indicates a negative or normal test result.

Abnormal results: Presence of cardiolipin antibodies indicates a positive or abnormal result.

Mild to moderate amount of ACL antibodies does not point to any specific condition.
However, high levels of cardiolipin antibodies indicate a high risk of excessive clotting (possibility of developing DVT, pulmonary embolism) or recurrent miscarriages.

Antiphospholipid syndrome is diagnosed if the aforementioned conditions are present. Antiphospholipid syndrome can be primary (not related to autoimmune disorders) or secondary (associated with autoimmune disorders).

In certain individuals, cardiolipin antibodies are evaluated along with venereal diseases (VDRL) such as syphilis. However, phospholipids are present in the reagent that tests for syphilis, which can result in a false-positive ACL test.

Three types of cardiolipin antibodies are present in the blood, viz. IgM, IgG and IgA. IgM and IgG are the most common variants that are tested, but when these are negative and yet symptoms are suspected, IgA variant is evaluated.

In some individuals, additional tests, such as platelet count, PTT (or APTT) and antinuclear antibodies (ANA), are also performed to conclude the diagnosis of an abnormal clotting process.

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational perspective and is in no way a substitute for medical advice from a qualified doctor.

और पढ़ें ...


  1. Lupus Foundation of America. Antiphospholipid antibody syndrome. Washington DC, USA. [internet].
  2. MSDmannual professional version [internet].Antiphospholipid Antibody Syndrome (APS). Merck Sharp & Dohme Corp. Merck & Co., Inc., Kenilworth, NJ, USA
  3. Johns Hopkins Lupus Center. Antiphospholipid Syndrome. John Hopkins medicine. [internet].
  4. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Antiphospholipid Antibody Syndrome
  5. National Health Service [Internet]. UK; Deep vein thrombosis
  6. National Health Service [Internet]. UK; Pulmonary embolism
  7. MedlinePlus Medical: US National Library of Medicine; Pulmonary Embolism
  8. University of Rochester Medical Center. Cardiolipin Antibody. Rochester, New York. [internet].