Myeloperoxidase concentrations in EDTA-plasma of healthy subjects are discordant with concentrations in heparin-plasma and serum

Objectives: To examine the effect of blood anticoagulation type on the myeloperoxidase (MPO) concentration. Design and methods: MPO was measured in EDTA-plasma and matched heparin-plasma and serum samples collected from healthy volunteers. Results: MPO concentrations in heparin-plasma and serum were higher than in EDTA-plasma (both P < 0.001). MPO in EDTA-plasma was not significantly correlated with MPO in either heparin-plasma or serum. Conclusions: For MPO measurements, EDTA-plasma is the preferred specimen as it appears unaffected by ex vivo release of MPO from leukocytes. (C) 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.