Mean platelet volume: comparison of three analysers towards standardization of platelet morphological phenotype

Introduction: The aim of this study was to show variability in the measurement of the mean platelet volume (MPV) depending on the instrument used. Methods: This prospective analysis was carried out to measure MPV with three instruments, in 30 healthy controls and 113 hospital patients. Results: Firstly, for values in the normal range, the values obtained with the Siemens Advia(R) 2120 are lower than those given by the Beckman Coulter LH750(R) (-0.89), which are in turn lower than those obtained with the Sysmex XE-2100D(R) (-1.11), which represents a 20-25% variation in the measurement. These results emphasize the lack of universal external calibration for MPV analysis and thus make any intercentre comparison of MPV impossible unless the automated haematology analyser used is indicated. Secondly, we stress the differences in behaviour of the instruments in the presence of abnormally large platelets, i.e. an underestimate of the platelet count and the MPV may be provided because instruments using impedance technology may fail to take into account these platelets, but they rightly flag them. Conclusion: To harmonize our procedures, we propose definitions of platelet size (normal size, macroplatelets and giant platelets) based on the coordinated interpretation of the MPV, the distribution of platelet volume and the morphological appearance.