An autoimmune disease is a disorder in which the body mistakenly attacks healthy tissues. There are over 80 different types of autoimmune diseases. Autoimmune diseases may result in fatigue, fever, destruction of one or more body tissues, abnormal growth of an organ, and changes in organ function. Several tests can be used to diagnose autoimmune diseases, including: antinuclear antibody tests, autoantibody tests, CBC, and C-reactive protein tests. Treatment typically involves medicine to control or reduce the immune systems response (meaning that the body will stop attacking itself). Other treatment varies based on the type of disease, for example, if the autoimmune disease affects your blood, you may need a blood transfusion, or you may need hormone supplements if your body is lacking hormones as a result of the disease.