title: Determination of anti-neutrophil cytoplasmic antibodies in small vessel vasculitis: Comparative analysis of different strategies.
abstract: BACKGROUND
  Anti-neutrophil cytoplasmic antibodies (ANCA) are associated with primary small vessel vasculitis (SVV). Proteinase-3 (PR3)-ANCA are primarily associated with Wegener granulomatosis, whereas myeloperoxidase (MPO)-ANCA are primarily associated with microscopic polyangiitis (MPA) and vasculitic Churg-Strauss syndrome. We evaluated whether a strategy that is based on screening with ELISA or fluoroenzymeimmunoassay (FEIA) is an accurate alternative to screening with indirect immunofluorescence (IIF).
  
  
  METHODS
  C-ANCA and P-ANCA were determined by IIF and PR3-ANCA and MPO-ANCA were determined by ELISA (Inova) or FEIA (Phadia) on 326 patients (38 with newly diagnosed SVV and 288 diseased controls).
  
  
  RESULTS
  Specificity and positive likelihood ratios were higher for ELISA and FEIA than for IIF. Post-test probability for SVV of a positive test result was higher for ELISA and FEIA than for IIF. Decision tree analysis in which several testing strategies were compared revealed that a testing strategy that is based on screening with ELISA or FEIA had an expected clinical utility that was comparable to screening with IIF and confirming with ELISA or FEIA. The highest expected clinical utility was found when both IIF and ELISA or FEIA were performed on all samples.
  
  
  CONCLUSIONS
  A strategy based on screening for ANCA with ELISA or FEIA (without prior IIF) is a valuable alternative to screening with IIF and confirming with ELISA or FEIA.
authors: Laboratory Medicine, Immunology, University Hospitals Leuven, Belgium.
authors: Pieter
authors: P
authors: Vermeersch
authors: Steven
authors: S
authors: Vervaeke
authors: Daniël
authors: D
authors: Blockmans
authors: Lieve
authors: L
authors: van Hoovels
authors: Godelieve
authors: G
authors: Mariën
authors: Hendrik
authors: H
authors: Vanmaele
authors: Xavier
authors: X
authors: Bossuyt
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D001323:Autoantibodies / Q000097:blood*; D001808:Blood Vessels / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D053146:Myeloblastin / Q000276:immunology; D009504:Neutrophils / Q000201:enzymology / Q000276:immunology; D009195:Peroxidase / Q000276:immunology; D012680:Sensitivity and Specificity; D014657:Vasculitis / Q000097:blood / Q000276:immunology*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D009195:Peroxidase; D053146:Myeloblastin