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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

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.