Unpredictable effects of K3 EDTA on mean platelet volume

The changes of mean platelet volumes (MPVs) begin immediately upon exposure of the blood to K3EDTA, and differences from sample to sample are unpredictable, predominantly in the first two hours from the venipuncture. MPVs variations can range from -25 to 23.1% in respect to MPVs in untreated whole blood immediately processed. These results were obtained by a new electrooptical device (Technicon H X 1) that provides complete blood cell counting and sizing. If whole blood is collected and diluted with a reagent used by the instrument to sphere and fix red blood cells and platelets, MPVs values do not change significantly within 180 minutes from venipuncture. This approach allows one to study the true values of MPVs on Technicon H X 1.