If you suspect you may have an autoimmune disease, the doctor will likely start out by conducting a physical examination and taking your personal and family medical history. He or she may also conduct tests to rule out other conditions. For most autoimmune diseases there is no definitive diagnostic test that can determine for sure whether or not you have the disease. Some autoimmune diseases do have blood tests or other tests available that may aid in their diagnosis. Other diseases may require imaging studies such as X-rays, computerized tomography (CT) scans, or magnetic resonance imaging (MRI).