Platelet volume: density relationships in normal and acutely bled dogs.

Abstract

Summary.The relationship between platelet volume and platelet density was studied in normal dogs and in dogs subjected to acute blood loss.Frequency distribution histograms of platelet densities were obtained by centrifuging diluted whole blood over a series of 13 silicone solutions varying in specific gravity from 1.007 to 1.065 and determining the percentage of platelets that remained in the supernatants above the silicone after centrifugation for 2 min at 9500 g. Frequency distribution histograms of platelet volumes were obtained using the Model B Coulter Counter with the Coulter Model H particle size analyser.Platelets of normal dogs have a skewed distribution of densities. The mean density is approximately 1.020 but the plateau region on the cumulative distribution of platelet densities is not reached until specific gravity 1.045‐1.050. Mean platelet volume increases as density increases.When platelet production was increased following acute blood loss, both mean density and mean volume increased abruptly, but the change in density histograms was more prolonged as well as more striking than change in mean density. Results of serial observations suggest that the large dense platelets produced following acute blood loss represent an aberrant population and that these platelets do not decrease in volume as they age.