Test Details: Autoantibodies are produced when a person’s immune system mistakenly targets and attacks the body’s own tissues. 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. The 4-test ENA panel is used to help diagnose mixed connective tissue disease (MCTD), lupus (SLE) and Sjogren syndrome. This test helps to diagnose and distinguish between autoimmune disorders as well as to monitor autoimmune disease progression.