Autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other body normal constituents. Any disease resulting from this type of immune response is termed an “autoimmune disease”.
There’s usually no single test to diagnose autoimmune disease. You have to have certain symptoms combined with specific blood markers and in some cases, even a tissue biopsy. It’s not just one factor. Diagnosis can also be difficult because these symptoms can come from other common conditions.