Extractable Nuclear Antigen (ENA) Panel

The ENA (extractable nuclear antigen) panel is a blood test that looks for antibodies to 6 or 7 different proteins in the body. These antibodies include:

• anti-Ro (also called anti-SSA)
• anti-La (also called anti-SSB)
• anti-Sm (anti-Smith antibody)
• anti-RNP (anti-ribonucleoprotein)
• anti-Jo-1
• anti-Scl70
• anti-centromere

These antibodies are types of autoantibodies: they are produced by the immune system and target something the body’s own tissues are made of. The ENA panel is usually ordered as a follow-up after a positive ANA (Anti-Nuclear Antibody) test in a person who has signs and symptoms of an autoimmune disease.

The ENA panel may be ordered to help make a diagnosis of the following autoimmune disorders:

• Systemic Lupus Erythematosus (SLE)
• Mixed connective tissue disease (MCTD)
• Sjögren’s syndrome
• Scleroderma

The results of the ENA panel can be difficult to interpret. It’s best to discuss this with your rheumatologist.