<prompt> Patient presenting with cutaneous vasculitis, glomerulonephritis, peripheral neuropathy, which investigation is to be performed next that will help you diagnose the condition?ANCARA factorHbsAMIF  <response>: Ans. a. ANCAANTINEUTROPHIL CYTOPLASMIC ANTIBODIESAntineutrophil cytoplasmic antibodies ANCAs are antibodies directed against certain proteins in the cytoplasm of neutrophils.The cytoplasmic c ANCA refers to the diffuse staining pattern observed when serum antibodies bind to indicator neutrophils; it is seen in90 of patients with Wegener granulomatosis.Perinuclear p ANCA refers to a localized staining pattern observed on the indicator neutrophils, the major target of these antibodies being the enzyme myeloperoxidase; it is found in PAN and Churg-Strauss but is a nonspecific test. 