title: Antigen-specific ANCA ELISAs have different sensitivities for active and treated vasculitis and for nonvasculitic disease.
abstract: This study evaluated the performance of 12 assays for antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) and myeloperoxidase (MPO) in 55 active and 68 treated cases of vasculitis and in nonvasculitic disease. It examined within- and between-assay precision; binding curves, binding levels, and interassay consistency; and sensitivity, specificity, and receiver operating characteristic analysis. All assays were highly sensitive for active vasculitis (median, 94%; range, 91%-96%), but sensitivities were more varied in treated disease (median, 69%; range, 57%-82%). Binding curves and binding levels were also very variable in PR3-ANCA and MPO-ANCA assays. This has implications for studies correlating ANCA levels with disease activity and in developing ANCA-based treatment guidelines. PR3-ANCA and MPO-ANCA assays need to be standardized as a matter of urgency, but in the meantime, individual laboratories must understand the limitations of the assays used, especially with low-level ANCA in treated vasculitis and nonvasculitic disease.
authors: Division of Laboratory Medicine, Austin Hospital, Heidelberg, Australia.
authors: Michelle
authors: M
authors: Trevisin
authors: Wendy
authors: W
authors: Pollock
authors: Wayne
authors: W
authors: Dimech
authors: Joy
authors: J
authors: Melny
authors: Bill
authors: B
authors: Paspaliaris
authors: David
authors: D
authors: Gillis
authors: Richard
authors: R
authors: Wong
authors: Judy
authors: J
authors: Savige
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D000939:Epitopes; D019084:Fluorescent Antibody Technique, Indirect; D014890:Granulomatosis with Polyangiitis / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D053146:Myeloblastin / Q000097:blood / Q000276:immunology; D009504:Neutrophils / Q000378:metabolism / Q000473:pathology; D009195:Peroxidase / Q000097:blood / Q000276:immunology; D011379:Prognosis; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D000939:Epitopes; D009195:Peroxidase; D053146:Myeloblastin