A composite elisa for the rapid diagnosis of ANCA-associated vasculitis and ANTI-GBM mediated disease

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and Goodpasture’s disease are conditions requiring rapid institution of treatment for optimal outcomes. Consequently a rapid diagnosis is important. We undertook an audit of the clinical and laboratory features of patients from Christchurch Hospital on whom a rapid vasculitis and anti-glomerular basement membrane (GBM) antibody screen was performed in the period 1 August 2003 to 30 July 2008. 109 patient samples were tested on the rapid screen using a modified in-house composite ELISA for anti-proteinase 3 (PR3), anti-myeloperoxidase (MPO) and anti-GBM antibodies. Fifty-three of these samples were also tested on routine ELISAs for those antibodies. The rapid screen for anti-GBM antibodies had a clinical sensitivity of 75% (95%CI 24.23–98.75) and specificity of 97.14% (92.42–99.27) for anti-GBM mediated disease. The MPO and PR3 screening tests had a sensitivity of 100% (79.42–100) and specificity of 93.83% (86.85–97.7) for ANCA-associated vasculitis. The composite ELISA provides a rapid result with high specificity for anti-GBM, anti-MPO and anti-PR3 antibodies.