Kim JH, et al. - Authors probed the relationship between mean platelet volume (MPV) and Birmingham vasculitis activity score (BVAS) in patients with MPA. The medical records of patients with MPA were retrospectively reviewed and clinical and laboratory data at diagnosis and partially at follow-up were collected. Experts noted an independent association of MPA with BVAS. Along with the improvement of vasculitis activity, MPV increased during the follow-up. Findings suggested a significant association of MPV with BVAS and the current BVAS in patients with MPA can be estimated by it.