Mean platelet volume artifacts: the effect of anticoagulants and temperature on canine platelets.

Improper handling of specimens results in artifactually high Mean Platelet Volume (MPV) measurements limiting their usefulness as a clinical tool. MPV measurement and Scanning Electron Microscopy (SEM) were performed on split specimens collected from normal dogs using two anticoagulants and two temperatures over a period of 4 hours. Platelets exposed to EDTA and maintained at 4 degrees C (39.2 degrees F) exhibited the highest artifactual increase in MPV, while those exposed to citrate and maintained at 37 degrees C (98.6 degrees F) exhibited minimal change. The increase in MPV was accompanied by platelet shape change from a smooth disc to an irregular sphere with filopodia. It is recommended that citrated specimens maintained at 37 degrees C be used in all MPV measurements.