This test is to detect/ diagnose/ monitor some forms of AUTOIMMUNE DISORDER SYSTEMIC VASCULITIS. Systemic vasculitis means inflammation of blood vessels. This test is used to identify whether the chronic pain in digestive tract is due to SYSTEMIC VASCULITIS (i.e. inflammation of blood vessels) or due to ulcer. To identify whether Anti Neutrophil Cytoplasmic Antibodies are present in the blood vessels of person having chronic pain in the digestive tract, this test is recommended.