title: Diagnostic value of distinguishing and reporting different perinuclear ANCA (P-ANCA) immunofluorescence patterns: a prospective study.
abstract: OBJECTIVE
  To investigate whether discriminating the classic perinuclear antineutrophil cytoplasmic antibody (P-ANCA) pattern from atypical P-ANCA and uninterpretable patterns improves the diagnostic utility of ANCA testing.
  
  
  METHODS
  All ANCA requests (n = 3,544) referred to Pathology Queensland were analyzed prospectively over 4 months for P-ANCA pattern subtypes and myeloperoxidase (MPO)-ANCA/PR3-ANCA results and correlated with clinical, laboratory, and radiologic evidence of necrotizing small vessel vasculitis.
  
  
  RESULTS
  Of the 436 perinuclear immunofluorescence-positive samples, 45 were classic P-ANCA, 163 were atypical P-ANCA, and 228 were antinuclear antibodies/uninterpretable. The classic P-ANCA pattern had a significantly stronger association with vasculitis (30/45) than atypical P-ANCA (2/163) (P <.0001) or ANA/uninterpretable patterns (8/228) (P <.0001). The combination of a classic P-ANCA pattern and positive MPO-ANCA/PR3-ANCA result was also more strongly associated with vasculitis than a positive MPO-ANCA/PR3-ANCA result in isolation (P = .003).
  
  
  CONCLUSIONS
  This study demonstrates that reporting different P-ANCA patterns (including ANA/uninterpretable patterns) provides additional diagnostic information to MPO-ANCA/PR3-ANCA results.
authors.affiliation: Division of Immunology, HSSA Pathology Queensland Central Laboratory, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Perel
authors.forename: Kerri M
authors.initials: KM
authors.lastname: Prain
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Wilson
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Hogan
authors.forename: David
authors.initials: D
authors.lastname: Gillis
authors.forename: Richard C W
authors.initials: RC
authors.lastname: Wong
mesh_terms: D000328:Adult; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000175:diagnosis* / Q000378:metabolism; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D011446:Prospective Studies; D011793:Queensland; D014657:Vasculitis / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic
keywords: Antineutrophil cytoplasmic antibodies; Antineutrophil cytoplasmic antibody–associated vasculitis; Enzyme-linked immunosorbent assay; Fluorescent antibody technique; Granulomatosis with polyangiitis; Microscopic polyangiitis; P-ANCA; Vasculitis