MPO and anti-neutrophil cytoplasmic antibody-associated vasculitis: Finally, the use of MPO-ANCA status, as opposed to MPO-ANCA titer changes, to guide clinical decisions seems advantageous because it is independent of different ANCA testing methodologies and thus allows standardized decisions that can be replicated across different centers, leading to homogeneous practices in remission-maintenance treatment in ANCA-associated vasculitis with GN.