The ANA test is ordered when someone shows signs and symptoms that are associated with a systemic autoimmune disorder. People with autoimmune disorders can have a variety of symptoms that are vague and non-specific and that change over time, progressively worsen.The antinuclear antibody (ANA) test is used as a primary test to help evaluate a person for autoimmune disorders that affect many tissues and organs throughout the body (systemic) and is most often used as one of the tests to help diagnose systemic lupus erythematosus (SLE). ANA are a group of autoantibodies produced by a person's immune system when it fails to adequately distinguish between "self" and "nonself." They target substances found in the nucleus of a cell and cause organ and tissue damage. Depending on a person's signs and symptoms and the suspected disorder, ANA testing may be used along with or followed by other autoantibody tests.