What is Extractable Nuclear Antigen(ENA) Profile?

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

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. Autoantibody association can aid in the diagnosis of an autoimmune disorder and help distinguish between other autoimmune 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 healthcare practitioners and patients it serves. Individual ENA panel tests can also be ordered separately.

How is the test used?

The ENA panel may be used as follow-up testing to a positive ANA test to help diagnose an autoimmune disorder. Testing may be used to help distinguish between autoimmune disorders as well as to monitor autoimmune disease progression.

The 4-test ENA panel is used to help diagnose mixed connective tissue disease (MCTD), lupus (SLE), and Sjögren syndrome. The 6-test ENA panel can also help identify scleroderma and polymyositis/dermatomyositis. For more on these diseases, see the links under Related Content below.

An ENA panel may also be used to monitor the activity of a particular autoimmune disorder in conjunction with clinical examination.