title: A comparison of commercial and in-house ELISAs for antineutrophil cytoplasmic antibodies directed against proteinase 3 and myeloperoxidase.
abstract: This study compares the concordance of results in different ELISAs for antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) or myeloperoxidase (MPO). Sera were considered "true positives" if they were positive according to the manufacturer's criteria in a least three of the five PR3-ANCA ELISAs, or in at least four of the six MPO-ANCA ELISAs. Of the 26 sera that demonstrated cytoplasmic fluorescence (C-ANCA), 23 (89%) contained PR3-ANCA and three (11%) had MPO-ANCA. Two sera that were negative by indirect immunofluorescence (IIF) contained PR3-ANCA. Of the 26 sera with perinuclear fluorescence (P-ANCA), 19 (73%) contained MPO-ANCA, and one (4%) had PR3-ANCA. Six sera with P-ANCA did not have PR3- or MPO-ANCA. No serum that was negative by IIF contained MPO-ANCA. For the different PR3-ANCA ELISAs, sensitivities ranged from 88 to 100%, and specificities from 91 to 100%. For the MPO-ANCA ELISAs, sensitivities varied from 59 to 100% and specificities from 83 to 100%. The highest sensitivity and specificity for both the PR3- and MPO-ANCA ELISAs were obtained with the IBL and Eurodiagnostica assays. The in-house PR3-ANCA ELISA performed slightly less well than the commercial assays, but the performance of the in-house MPO-ANCA assay was comparable or better.
authors.affiliation: Immunology Department, Gribbles Pathology, South Yarra, Australia.
authors.forename: W
authors.initials: W
authors.lastname: Pollock
authors.forename: K
authors.initials: K
authors.lastname: Dunster
authors.forename: J M
authors.initials: JM
authors.lastname: Rolland
authors.forename: H
authors.initials: H
authors.lastname: Koh
authors.forename: J
authors.initials: J
authors.lastname: Savige
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D053146:Myeloblastin; D009195:Peroxidase / Q000276:immunology*; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D012697:Serine Endopeptidases / Q000276:immunology*; D014657:Vasculitis / Q000097:blood
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D011933:Reagent Kits, Diagnostic; D009195:Peroxidase; D012697:Serine Endopeptidases; D053146:Myeloblastin