Extractable Nuclear Antigen Antibodies (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 (Sm)
- Smith Antibody
- Scl-70
- Anti-Topoisomerase
- Scleroderma Antibodies
- Anti-Jo-1
- Antihistidyl Transfer RNA Synthase Antibodies
- ENA Panel
- Formal Name:
- Extractable Nuclear Antigen Antibodies

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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 and 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
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The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.
If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.
Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.
While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”
For more information, please read the article Reference Ranges and What They Mean.
What is being tested?
An extractable nuclear antigen (ENA) panel detects the presence of 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 and represent six main proteins (Ro, La, Sm, RNP, Scl-70 and Jo1).
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, such as mixed connective tissue disease (MCTD), lupus (SLE), Sjögren syndrome, scleroderma, and polymyositis/dermatomyositis. Autoantibody association can aid in the diagnosis of an autoimmune disorder and help distinguish between other autoimmune disorders. For more on these conditions, see the links in Related Content below.
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 healthcare 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 |
Anti-Scl-70 | Scleroderma Antibodies; anti-topoisomerase |
Anti-Jo-1 | Anti-Histidyl Transfer RNA Synthase Antibodies |
Common Questions
View Sources
Sources Used in Current Review
2017 review completed by Boris Calderon, MD, DABCC, FAACC, Associate Medical Advisor, Eli Lilly and Company.
Aggarwal A. Role of autoantibody testing. Best Pract Res Clin Rheumatol. 2014 Dec;28(6):907-20. doi: 10.1016/j.berh.2015.04.010. Epub 2015 May 23. Available online at http://www.sciencedirect.com/science/article/pii/S1521694215000170?via%3Dihub. Accessed on 6/15/2017.
Ortega-Hernandez O, Shoenfeld Y. Mixed connective tissue disease: An overview of clinical manifestations, diagnosis and treatment. Best Pract Res Clin Rheumatol. 2012 Feb;26(1):61-72. doi: 10.1016/j.berh.2012.01.009. Available online at http://www.sciencedirect.com/science/article/pii/S1521694212000101. Accessed on 6/15/2017.
Arthur Kavanaugh, Russell Tomar, John Reveille, Daniel H. Solomon, and Henry A. Homburger. (2000) Guidelines for Clinical Use of the Antinuclear Antibody Test and Tests for Specific Autoantibodies to Nuclear Antigens. Archives of Pathology & Laboratory Medicine: January 2000, Vol. 124, No. 1, pp. 71-81. Arch Pathol Lab Med. 2000 Jan;124(1):71-81. Available online at http://www.archivesofpathology.org/doi/full/10.1043/0003-9985%282000%29124%3C0071%3AGFCUOT%3E2.0.CO%3B2. Accessed on 6/15/2017.
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. 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. 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#. 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. 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. 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. 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. 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. 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.
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. 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. 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. 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.
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