Platelet count and plateletcrit in Cavalier King Charles Spaniels and Greyhounds using the Advia 120/2120

Abstract

Background: Models for the regulation of thrombopoiesis predict that platelet mass is the biologically regulated parameter, yet clinical evaluations are often based on platelet number. When there is concurrent thrombocytopenia and variation in platelet size, platelet count may poorly estimate total platelet mass, confounding clinical decision making. Objective: We hypothesize that plateletcrit provides clinically important information when platelet number is an incomplete representation of platelet mass, such as in genetic macrothrombocytopenia. Methods: We retrospectively compared platelet count and plateletcrits with general reference intervals for four groups of dogs: sick Cavalier King Charles Spaniels and Greyhounds that presented for non-hematopoietic disease to the University of Minnesota (Advia 2120) and Auburn University Teaching Hospitals (Advia 120) over a 3 year period. Results: A canine plateletcrit reference interval of 0.129 – 0.403 % was established. None of the four sample groups were found to have significantly more individuals below the reference interval for plateletcit. For platelet count, only the Cavalier groups were found to have significantly more individuals below the reference interval than predicted. Conclusion: Use of the plateletcrit as determined by the Advia 120/2120 appeared to avoid overestimation of low platelet mass in sick Cavalier Kind Charles Spaniels in a clinical setting. In contrast, the plateletcrit performed similarly to the platelet count in evaluation of platelet mass in sick Greyhounds. Evaluation of the plateletcrit should be considered in other conditions associated with increased mean platelet volume.