what is anca blood test
Tests for antineutrophil cytoplasmic antibodies (ANCA) may be used to: 1  Help detect and diagnose certain forms of autoimmune vasculitis, including granulomatosis with polyangiitis (Wegener granulomatosis), microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis (Churg Strauss syndrome).egative ANCA tests results mean it is unlikely that a person's symptoms are due to an autoimmune vasculitis. For a positive result on the indirect immunofluorescence microscopy method, several different ANCA patterns may be seen: 1  Perinuclear (pANCA) â most of the fluorescence occurs near the nucleus.