Mean platelet volume is a useful parameter: a reproducible routine method using a modified Coulter Thrombocytometer

The principal physiological function of platelets is to promote haemostasis but they also contribute to thrombosis and atherogenesis. Platelet volume is a marker and possibly a determinant of platelet function in that large p latelets are more active than normal sized platelets. Mean platelet volume (MPV), a measure of platelet size, reflects changes in either the level of platelet stimulation or the rate of platelet production. For these reasons, we have developed a sensitive instrument to measure platelet volume, which we believe is more reliable and specific than previously used instruments. It is based on a computer-interfaced Coulter Thrombocytometer and a pulse analyser including a high-speed baseline restorer. We have developed a repr oducible method to assay MPV and from the histogram derived the median (MED ) and the skewness (SK) values. We have looked at the effects of anticoagul ant used and time elapse prior to assay. A normal range has been establishe d for MPV which correlates directly with MED and inversely with SK. The MPV decreases with age but there is no difference between genders. We have dem onstrated a negative correlation between whole blood platelet number and MP V and MED, and a direct relationship with the SK of the histogram of the pl atelet volume.