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Antiphospholipid Antibodies

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Also known as: APA
Formal name: Antiphospholipid Antibodies
Related tests: Lupus Anticoagulant Testing, Cardiolipin Antibodies, PTT, Platelet Neutralization Procedure, Kaolin Clotting Time, Hexagonal Phospholipid Confirmatory Test, Dilute Prothrombin Time, Beta-2 Glycoprotein 1 Antibodies, Antiphosphatidylserine Antibodies, Antiprothrombin Antibodies

At a Glance

Why Get Tested?

To help investigate inappropriate blood clot formation; to help determine the cause of recurrent miscarriage; to evaluate a prolonged PTT (partial thromboplastin time); as part of an evaluation for antiphospholipid syndrome (APS); sometimes to help diagnose or evaluate an autoimmune disorder

When to Get Tested?

When you have a prolonged PTT test; when you have had recurrent unexplained blood clots; when you have had recurrent miscarriages, especially in the second and third trimesters

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Antiphospholipid antibodies are immune proteins that the body mistakenly produces against itself in an autoimmune response to phospholipids. These tests detect these autoantibodies that bind to phospholipids and, in a way that is not well understood, increase the risk of excessive blood clotting.

Several tests are available, including:

Phospholipids are a normal part of the body. They are lipid molecules found in the outer-most layer of cells (cell membranes) and platelets and they play a crucial role in blood clotting. When antiphospholipid antibodies are produced, they interfere with the clotting process. They increase an affected person's risk of developing recurrent inappropriate blood clots (thrombi) in arteries and veins, which can lead to strokes and heart attacks. Antiphospholipid antibodies are also associated with low platelet counts (thrombocytopenia) and with the risk of recurrent miscarriages (especially in the second and third trimester), premature labor, and preeclampsia.

One or more antiphospholipid antibodies are frequently seen with autoimmune disorders such as systemic lupus erythematosus (SLE), also called lupus. They may also be seen with HIV, some cancers, in the elderly, and temporarily with infections and with some drug treatments (such as phenothiazines and procainamide).

Antiphospholipid syndrome (APS), also called Hughes syndrome, is a recognized group of signs and symptoms that includes the formation of thrombi, miscarriages, thrombocytopenia, and the presence of one or more antiphospholipid antibodies. APS can be primary with no underlying autoimmune disorder or secondary, existing with a diagnosed autoimmune disorder.

The most common tests for detecting antiphospholipid antibodies are cardiolipin antibodies and lupus anticoagulant assays. Others that are not as frequently used include beta2 glycoprotein I antibodies and anti-phosphatidylserine antibodies.

Lupus anticoagulant assays include RVVT (Russell viper venom time) and hexagonal phase lipid neutralization; platelet neutralization procedure can also be used to confirm lupus anticoagulant but is less commonly used nowadays.

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.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Rodgers, G. et. al. (Updated 2012 November). Antiphospholipid Syndrome – APS. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/APS.html?client_ID=LTD through http://www.arupconsult.com. Accessed January 2013.

(© 2013). Antiphospholipid Antibodies. Lupus Foundation [On-line information]. Available online at http://www.lupus.org/webmodules/webarticlesnet/templates/new_learnaffects.aspx?articleid=2302&zoneid=526 through http://www.lupus.org. Accessed January 2013.

Hammad, T. (Updated 2012 August 16). Antiphospholipid Antibodies. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2116457-overview through http://emedicine.medscape.com. Accessed January 2013.

Wijetilleka, S. et. al. (2012 September). Novel Insights Into Pathogenesis, Diagnosis and Treatment of Antiphospholipid Syndrome. Medscape Today News from Curr Opin Rheumatol. 2012;24(5):473-481 [On-line information]. Available online at http://www.medscape.com/viewarticle/769627 through http://www.medscape.com. Accessed January 2013.

Berg, T. (2012 November 21). Antiphospholipid Syndrome and Pregnancy. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/261691-overview through http://emedicine.medscape.com. Accessed January 2013.

(2012 May 17). What Is Antiphospholipid Antibody Syndrome? National Heart Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/health/health-topics/topics/aps/ through http://www.nhlbi.nih.gov. Accessed January 2013.

(© 1995-2013). Phospholipids, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/8296 through http://www.mayomedicallaboratories.com. Accessed January 2013.

(Updated 2010 December 15). Learning About Antiphospholipid Syndrome (APS). National Human Genome Research Institute [On-line information]. Available online at http://www.genome.gov/17516396 through http://www.genome.gov. Accessed January 2013.

Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 71-72.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

(2001 June 26). Antiphospholipid Antibody Syndrome. Hematology Resource Page, Patient Resources University of Illinois - Urbana/Champaign, Carle Cancer Center [On-line information]. Available online at http://www-admin.med.uiuc.edu/hematology/PtAPS.htm through http://www-admin.med.uiuc.edu.

(© 2004). Antiphospholipid Testing. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_al67.jsp#3965115 through http://www.arup-lab.com.

(© 2004). Beta-2 Glycoprotein, Antibody. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_al95.jsp#1145254 through http://www.arup-lab.com.

(© 2004). Cardiolipin Antibodies, IgG and IgM. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_a133.jsp#1059158 through http://www.arup-lab.com.

Lupus Anticoagulant Panel with Reflex to 1:1 Mixes and Confirmations. ARUP's Guide to Clinical Laboratory Testing [On-line information]. Available online at http://www.arup-lab.com/guides/clt/tests/clt_a52b.jsp#1141319 through http://www.arup-lab.com.

Zepf, B. (2002 June 1). A Discussion of the Antiphospholipid Syndrome. American Family Physician, Tips from other Journals, [From Levine JS, et al. The antiphospholipid syndrome. N Engl J Med March 7, 2002;346:752-63] [On-line journal]. Available online at http://www.aafp.org/afp/20020601/tips/11.html through http://www.aafp.org.

Petri, M. (2001). Antiphospholipid Antibodies: Anticardiolipin Antibodies and the Lupus Anticoagulant in Systemic Lupus Erythematosus. The Lupus Foundation of America [On-line information]. Available online at http://www.lupus.org/education/brochures/antiphos02.html through http://www.lupus.org.

Solenski, N. (2004 April 1). Transient Ischemic Attacks: Part I. Diagnosis and Evaluation. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20040401/1665.html through http://www.aafp.org.

The Thrombophilias and Pregnancy. March of Dimes, Professionals and Researchers, Quick References and Fact Sheets [On-line information]. Available online at http://www.marchofdimes.com/professionals/681_9264.asp through http://www.marchofdimes.com.

(2001). Antiphospholipid Antibody. Massachusetts General Hospital, Laboratory Medicine, Coag Test Handbood Index [On-line information From: Elizabeth M. Van Cott, M.D., and Michael Laposata, M.D., Ph.D., "Coagulation." In: Jacobs DS et al, ed. The Laboratory Test Handbook, 5th Edition. Lexi-Comp, Cleveland, 2001; 327-358.]. Available online at http://www.mgh.harvard.edu/labmed/lab/coag/handbook/CO003100.htm through http://www.mgh.harvard.edu.

De Moerloose P Antiphospholipid antibodies: do we still need to perform anticardiolipin assays? J Thromb Haemost 2004; 2:1071-1073 and Nash MJ et al.

The anticardiolipin assay is required for sensitive screening for antiphospholipid antibodies. J Thromb Haemost 2004; 2:1077-1081.

Brandt J et al. Criteria fort the diagnosis of Lupus anticoagulants: an update on behalf of the subcommittee on Lupus Antiocoagulant/Antiphospholipids Antibody of the Scientific and Standardization Committee of the ISTH. Thromb Haemost 1995:74:1185-1190.

Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 134-135.

National Institute of Neurological Disorders and Stroke. NINDS Antiphospholipid Syndrome Information Page. [On-line information. 2007 February 08, Updated.]. Available online at http://www.ninds.nih.gov/disorders/antiphosphlipid/antiphospholipid.htm through http://www.ninds.nih.gov. Accessed on 4/12/08.

American Heart Association. Antiphospholipid Syndrome (APLS). [On-line information. © 2008).]. Available online at http://www.americanheart.org/presenter.jhtml?identifier=4459 through http://www.americanheart.org. Accessed on 4/12/08.

Belilos, E. and Carsons, S. Antiphospholipid Syndrome. eMedicine [On-line information. 2007 August 10, Updated.]. Available online at http://www.emedicine.com/med/topic2923.htm through http://www.emedicine.com. Accessed on 4/12/08.

Lupus Foundation of America. Antiphospholipid Antibodies. [On-line information. © 2008.]. Available online at http://www.lupus.org/webmodules/webarticlesnet/templates/new_aboutaffects.aspx?articleid=82&zoneid=17 through http://www.lupus.org. Accessed on 4/12/08.

APS Foundation of America. Antiphospholipid Antibody Syndrome. [On-line information. 2006 October 15, Revised.]. Available online at http://www.apsfa.org/aps.htm through http://www.apsfa.org. Accessed on 4/19/08.

ARUP Consult. Antiphospholipid Syndrome – APS. [On-line information. © 2006-2008.]. Available online at http://www.arupconsult.com/Topics/HematologicDz/APS.html# through http://www.arupconsult.com. Accessed on 4/19/08.

National Human Genome Research Institute. Learning About Antiphospholipid Syndrome (APS). [On-line information. 2008 February 5, Reviewed. ]. Available online at http://www.genome.gov/17516396 through http://www.genome.gov. Accessed on 4/20/08.

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