Antineutrophil Cytoplasmic Antibody
Autoimmune diseases cause the body to attack itself, which leads to inflammation and results in damage to muscles, tissues, and organs. The body produces antibodies specific to each autoimmune disease; the antibody levels measured in your blood are then used by your doctor to diagnose the disease that is causing your symptoms. ANCA is a blood test that is mainly used to diagnose Wegener's granulomatosis (WG), which causes damage to the blood vessels of the nose and throat, lungs, and kidneys. This test is also used to monitor your response to treatment, and can be used to predict a relapse.
Two different ANCA tests are used: proteinase 3-ANCA which is very specific for WG affecting mainly the nose and throat; myeloperoxidase-ANCA (MPO-ANCA) is very specific for WG affecting the kidneys.
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