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Lupus anticoagulants and antiphospholipid antibodies


Lupus anticoagulants are antibodies against substances in the lining of cells. These substances prevent blood clotting in a test tube. They are called phospholipids.

People with antibodies to phospholipids (aPL) may have an overly high risk of forming blood clots. In spite of the name "anticoagulant" there is no increased risk of bleeding.


Most often lupus anticoagulants and aPL are found in people with diseases such as systemic lupus erythematosus (SLE).

Lupus anticoagulants and aPL may also occur if:

  • You take medicines such as phenothiazines, phenytoin, hydralazine, quinine, or the antibiotic amoxicillin.
  • You have a condition such as inflammatory bowel disease (Crohn disease and ulcerative colitis), infections, or certain kinds of tumors.

Some people have no risk factors for this condition.


You may not have any symptoms even though you have the antibodies. Symptoms that may occur include:

Exams and Tests

The following tests may be done:

Lupus anticoagulant tests. These are blood clotting tests. The antiphospholipid antibodies (aPL) cause the tests to be abnormal in the laboratory.

Types of clotting tests may include:

  • Activated Partial thromboplastin time (aPTT)
  • Russell viper venom time
  • Thromboplastin inhibition test

Tests for antiphospholipid antibodies (Apl) may include:

  • Anticardiolipin antibody tests
  • Antibodies to beta-2-glypoprotein I (Beta2-GPI)

Your provider may make the diagnosis of antiphospholipid antibody syndrome (APS) if:

  • You have had a blood clot or repeated miscarriages and you have positive tests for aPL or the lupus anticoagulant.
  • You have a positive test without other indications of the disease, and have another positive result when the test is repeated after 12 weeks.



Often, you will not need treatment if you do not have symptoms or if you have never had a blood clot in the past.

Take the following steps to help prevent blood clots from forming:

  • Avoid most birth control pills or hormone treatments for menopause (women).
  • DO NOT smoke or use other tobacco products.
  • Get up and move around during long plane flights or other times when you have to sit or lie down for extended periods.
  • Move your ankles up and down when you cannot move around.

You will be prescribed blood thinning medicines (such as heparin and warfarin) to help prevent blood clots:

  • After surgery
  • After a bone fracture
  • With active cancer
  • When you need to set or lie down for long periods of time, such as during a hospital stay or recovering at home.

You may also need to take blood thinners for 3 to 4 weeks after surgery to lower your risk of blood clots.


In general you will need long-term treatment with blood thinner for a long time if you have the APS. Initial treatment may be heparin, either unfractionated or low-molecular heparin. These medicines are given by injection.

In most cases, warfarin (Coumadin), which is given by mouth, is then started. It is necessary to monitor the level of anticoagulation frequently. This is most often done using the INR test.

If you have APS and become pregnant, you will need to be followed closely by a provider expert in this condition. You will not take warfarin during pregnancy but will be given low-molecular weight heparin instead.

If you have systemic lupus erythematosus (SLE) and APS your provider will also recommend that you take hydroxychloroquine.

Outlook (Prognosis)

Most of the time, outcome is good with proper treatment. Some people may have blood clots that are hard to control with treatments. Symptoms may recur.

When to Contact a Medical Professional

Call your health care provider if you notice symptoms of a blood clot, such as:

  • Swelling or redness in the leg
  • Shortness of breath
  • Pain, numbness, and pale skin color in an arm or leg

Also talk to your provider if you have repeated loss of pregnancy (miscarriage).


Barbhaiya M, Erkan D. Primary thrombosis prophylaxis in antiphospholipid antibody-positive patients: where do we stand? Curr Rheumatol Rep 2011; 13:59. PMID: 21104348

Chaturvedi S, McCrae KR. Recent advances in the antiphospholipid antibody syndrome. Curr Opin Hematol. 2014 21(5):371-9. PMID: 25023470

Doruk E, Salmon JE, Lockshin MD. Antiphospholiid syndrome. In: Firestein GS, Budd RC, Harris ED Jr, et al, eds. Kelley's Textbook of Rheumatology. 9th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 82.

Holbrook A, Schulman S, Witt DM, et al. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141:e152S. PMID: 22315259

Review Date: 1/20/2015
Reviewed By: Gordon A. Starkebaum, MD, Professor of Medicine, Division of Rheumatology, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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