ANCA stands for antineutrophil cytoplasmic antibodies, which are autoantibodies that target a type of white blood cell called neutrophils. ANCA testing is a blood test that looks for these antibodies in a sample of your blood. There are two main types of ANCAs: cANCA and pANCA, each of which targets a specific protein inside white blood cells. ANCA testing helps healthcare providers diagnose certain kinds of vasculitis, which is a group of autoimmune disorders that causes inflammation of the blood vessels. The types of vasculitis associated with ANCA are granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis. ANCA testing can show whether you have one or both types of antibodies, which helps your healthcare provider diagnose which type of autoimmune vasculitis you have so you can get the right treatment.