ENA Panel

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Also known as: Antibodies to Saline-extracted Antigens; Anti-RNP; Anti-Ribonucleoprotein; Anti-U(1)RNP; Anti-SmRNP; Anti-SSA; SSA (Ro); Anti-Sjögren Syndrome A; Anti-SSB; SSB (La); Anti-Sjögren Syndrome B; Anti-Sm; Smith Antibody; Scl-70; Anti-Topoisomerase; Scleroderma Antibodies; Anti-Jo-1; Antihistidyl Transfer RNA Synthase Antibodies
Formal name: Extractable Nuclear Antigen Antibodies
Related tests: ANA; Autoantibodies; Anti-dsDNA

At a Glance

Why Get Tested?

To help diagnose and distinguish between autoimmune disorders as well as to monitor autoimmune disease progression

When to Get Tested?

When your antinuclear antibody (ANA) test is positive; when you have symptoms that suggest an autoimmune disorder; when monitoring the activity of an autoimmune disorder

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

An extractable nuclear antigen (ENA) panel detects the presence of one or more autoantibodies in the blood that react with proteins in the cell nucleus. These proteins are known as "extractable" because they can be removed from cell nuclei using saline.

Autoantibodies are produced when a person's immune system mistakenly targets and attacks the body's own tissues. This attack can cause inflammation, tissue damage, and other signs and symptoms that are associated with an autoimmune disorder.

Certain autoimmune disorders are characteristically associated with the presence of one or more anti-ENA antibodies. This association can be used to help diagnose an autoimmune disorder and to distinguish between disorders.

The ENA panel typically consists of a group of 4 or 6 autoantibody tests. The number of tests performed will depend on the laboratory and the needs of the health practitioners and patients it serves. Individual ENA panel tests can also be ordered separately.

A 4-test ENA panel will include:

Autoantibody Test Formally Known As
Anti-RNP Anti-U(1)RNP, Anti-Ribonucleoprotein
Anti-Sm Smith Antibody
Anti-SS-A (Ro) Anti-Sjögren Syndrome A
Anti-SS-B (La) Anti-Sjögren Syndrome B

A 6-test ENA panel will include the four tests listed above as well as:

Autoantibody Test Formally Known As
Scl-70 Scleroderma Antibodies; anti-topoisomerase
Anti-Jo-1 Antihistidyl Transfer RNA Synthase Antibodies

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

Bartels, Christie M., et al. (Updated Jan. 28, 2013.) Systemic Lupus Erythematosus (SLE) Workup. Medscape online. Available online at http://emedicine.medscape.com/article/332244-workup through http://emedicine.medscape.com. Accessed January 2014.

Orton, Susan M., et al. (March 2004). Practical Evaluation of Methods for Detection and Specificity of Autoantibodies to Extractable Nuclear Antigens. American Society for Microbiology, Clinical and Vaccine Immunology online. Available online at http://cvi.asm.org/content/11/2/297.full through http://cvi.asm.org. Accessed January 2014.

Antibodies to Extractable Nuclear Antigens. Children's Hospitals and Clinics of Minnesota. Available online at http://www.childrensmn.org/Manuals/Lab/FlowCyt/018959.pdf through http://www.childrensmn.org. Accessed January 2014.

Kavanaugh, Arthur, et al. (January 2000.) Guidelines for Clinical Use of the Antinuclear Antibody Test and Tests for Specific Autoantibodies to Nuclear Antigens. Archives of Pathology and Laboratory Medicine. Available online through http://www.archivesofpathology.org. Accessed January 2014.

Sources Used in Previous Reviews

(© 1995-2010). Unit Code 89035: Antibody to Extractable Nuclear Antigen Evaluation, Serum. Mayo Clinic, Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/89035 through http://www.mayomedicallaboratories.com. Accessed March 2010.

(© 2006-2010). Extractable Nuclear Antigen Antibodies (RNP, Smith, SSA, & SSB): 0050652. ARUP's Laboratory Test Directory [On-line information]. Available online at http://www.aruplab.com/guides/ug/tests/0050652.jsp through http://www.aruplab.com. Accessed March 2010.

Hill, H. and Tebo. (Updated 2009 November). Mixed Connective Tissue Disease – MCTD. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/MCTD.html?client_ID=LTD# through http://www.arupconsult.com. Accessed March 2010.

Hill, H. and Tebo. (Updated 2009 August). Connective Tissue Diseases. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/ConnectiveTissueDz.html?client_ID=LTD through http://www.arupconsult.com. Accessed March 2010.

(© 1995-2010). Unit Code 83631: Connective Tissue Diseases Cascade, Serum. Mayo Clinic, Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/print.php?unit_code=83631 through http://www.mayomedicallaboratories.com. Accessed March 2010.

Klein-Gitelman, M. (Updated 2009 September 29). Mixed Connective Tissue Disease. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/1006966-overview through http://emedicine.medscape.com. Accessed March 2010.

Hildebrand Jr., G. and Battafarano, D. (Updated 2009 July 24). Undifferentiated Connective Tissue Disease. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/334482-overview through http://emedicine.medscape.com. Accessed March 2010.

Hajj-ali, R. (Revised 2008 February) Mixed Connective Tissue Disease (MCTD). Merck Manual for Healthcare Professionals [On-line information]. Available online at http://www.merck.com/mmpe/sec04/ch032/ch032c.html through http://www.merck.com. Accessed March 2010.

Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 81-82.

Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 128-129, 136-139.