ANCA testing identifies autoantibodies that target enzymes in neutrophils, immune cells involved in inflammation. Two main patterns — cytoplasmic (c-ANCA, typically directed against PR3) and perinuclear (p-ANCA, typically directed against MPO) — are associated with different vasculitic diseases.
This test is used to evaluate patients with unexplained sinopulmonary disease, kidney inflammation, neuropathy, or systemic symptoms suggesting vasculitis. Positive results, particularly with high titers, support a diagnosis of ANCA-associated vasculitis and prompt urgent treatment in many cases. Sample type is serum.