Antineutrophil cytoplasmatic antibodies (ANCA) are used as a diagnostic marker for Wegener’s granulomatosis (WG), microscopic polyangiitis (MPA) and Churg-Strauss syndrome (CSS), as high levels of ANCA are found in these conditions. Consensus guidelines currently recommend performing an immunofluorescence test (IFT) together with an ELISA to detect the ANCA pattern and the target antigen.1 Conventional ELISAs using proteinase 3 (PR3) immobilised to the surface of the ELISA plate show great variations in performance and often lack sensitivity.2 Capture ELISA is superior in overall diagnostic performance to direct ELISA,2 but the sensitivity of capture ELISA may be reduced by the capturing antibodies hiding relevant epitopes. hsPR3-ANCA ELISA immobilises PR3 …