MPO and vasculitis: Screening for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and multiple myeloma was also negative, with negative results for Bence-Jones protein, antinuclear antibody (ANA), anti-glomerular basement membrane antibody (anti-GBM Ab), myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA), and proteinase 3 anti-neutrophil cytoplasmic antibody (PR3-ANCA).