[Measurement of platelet volume: methodologic approach and application in diabetes]

A comparative study of platelet count and platelet volume distribution was performed on whole blood (Coulter counter S+) or platelet rich plasma (Thrombo Coulter and Coulter ZBI + Channelyser C 1 000). With the exception of severe thrombocytopenia the results of platelet counts obtained with the coulter S + were very reproducible (CV less than 4%) and a good correlation was observed between results obtained on whole blood and on platelet rich plasma (PRP). The mean platelet volume (MPV) was significantly higher in whole blood than in PRP, but the difference was very slight, suggesting that platelet volume distribution in PRP and in whole blood are similar. In whole blood collected in EDTA MPV increased significantly during the 2 hours after blood collection and then reached a plateau. This finding underlines the need for a standard technique. Preliminary results obtained with the Coulter S + in 86 diabetic patients and in 73 unselected control subjects demonstrated a significant increase of MPV and of the index of platelet distribution (IDP) given by the apparatus, without modification of platelet count in diabetics. These results could suggest a compensated increased platelet consumption in the circulating blood.