Different autoimmune diseases can have different symptoms. No single test can diagnose most autoimmune diseases. A doctor will order tests, review your symptoms, and conduct a physical examination to reach a diagnosis.
Doctors often use the antinuclear antibody test when your symptoms indicate an autoimmune disease. A positive test means you may have one of these diseases, but it won’t confirm exactly which one you have or if you have one for sure.
Other tests look for specific autoantibodies produced in certain autoimmune diseases. A doctor may also order nonspecific tests to check for the inflammation these diseases produce in the body.