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 are types of autoantibodies: antibodies that are produced by the immune system that 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.