A critical evaluation of commercial immunoassays for antineutrophil cytoplasmic antibodies directed against proteinase 3 and myeloperoxidase in Wegener's granulomatosis and microscopic polyangiitis

Rheumatology (Oxford). 2002 Nov;41(11):1313-7. doi: 10.1093/rheumatology/41.11.1313.


Objective: To evaluate the performance of 11 commercial enzyme-linked immunosorbent assay (ELISA) kits for the detection of antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) and myeloperoxidase (MPO) in patients with Wegener's granulomatosis (WG) and microscopic polyangiitis (MPA).

Methods: Serum samples were taken from 92 patients with a histological and clinical diagnosis of WG (n=50) or MPA (n=42) and from 30 disease controls (systemic lupus erythematosus, n=15; rheumatoid arthritis, n=15) and 30 healthy controls. Each of the sera was tested for the presence of ANCA directed against PR3 and MPO using 11 commercially available direct ELISA kits, our in-house PR3- and MPO-ANCA capture ELISAs, and the indirect immunofluorescence technique (IFT).

Results: In tests for WG using PR3-ANCA, the commercial direct ELISA kits differed widely in their sensitivity (from 22 to 70%) and negative predictive value (NPV) (from 43 to 70%), but only moderately in their specificity (from 93 to 100%) and positive predictive value (PPV) (from 93 to 100%). The highest sensitivity (74%) and specificity (100%) for PR3-ANCA were obtained with the in-house capture ELISA. Similar differences and trends were noted for MPO-ANCA assays. Diagnostic sensitivity was more than 60% for four and at least 50% for six of the 11 ELISA kits. The PPV varied from 84 to 100% and the NPV from 58 to 70%. In tests for MPA, the MPO-ANCA ELISA kit designated F and the in-house capture ELISA were best (both had sensitivity 62% and specificity 100%). For both WG and MPA, maximum sensitivity for ANCA was obtained with IFT (80 and 70% respectively).

Conclusion: Determination of PR3-ANCA and MPO-ANCA with the commercial direct ELISA kits achieved poor sensitivity for both WG and MPA. The in-house PR3 and MPO-ANCA capture ELISAs performed better than the commercial ELISAs, combining higher specificity with similar sensitivity. IFT remains the best method for ANCA detection in both diseases.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Antineutrophil Cytoplasmic / analysis*
  • Case-Control Studies
  • Enzyme-Linked Immunosorbent Assay*
  • Female
  • Fluorescent Antibody Technique, Indirect*
  • Granulomatosis with Polyangiitis / blood*
  • Granulomatosis with Polyangiitis / immunology
  • Humans
  • Male
  • Middle Aged
  • Myeloblastin
  • Peroxidase / immunology*
  • Predictive Value of Tests
  • ROC Curve
  • Reagent Kits, Diagnostic
  • Reference Values
  • Sensitivity and Specificity
  • Serine Endopeptidases / immunology*
  • Vasculitis / blood*
  • Vasculitis / immunology


  • Antibodies, Antineutrophil Cytoplasmic
  • Reagent Kits, Diagnostic
  • Peroxidase
  • Serine Endopeptidases
  • Myeloblastin