Test Background Anti-neutrophil cytoplasmic antibodies (ANCA) are directed against cytoplasmic constituents of polymorphonuclear leukocytes and monocytes. Most patients with primary small vessel vasculitis, eg. Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome and limited forms of these diseases, harbour ANCA directed against either PR3 (proteinase 3) or MPO (myeloperoxidase). They are used as specific markers for Wegener's granulomatosis and other diseases, though their pathophysiological role is not clear. ANCA are routinely detected by indirect immunofluorescence with three different patterns: c-ANCA (cytoplasmic), p-ANCA (perinuclear), and atypical ANCA.
Clinical Indications Skin rashes with or without pain (cutaneous vasculitis)
General (protean) symptoms, such as feeling unwell, weight loss, night sweats, joint pains
Haemoptysis, difficulty in breathing (lungs)
Muscle weakness/numbness of extremities (microvascular)
Abdominal pain (gut)
In addition to acute heart and brain symptoms when these organs are implicated
Suspected Wegener's granulomatosis, microscopic polyangiitis or Churg-Strauss syndrome