Platelet parameters from an automated hematology analyzer in dogs with inflammatory clinical diseases.

The mean platelet component (MPC) is a proprietary algorithm of an automated laser-based hematology analyzer system which measures the refractive index of platelets. The MPC is related linearly to platelet density and is an indirect index of platelet activation status. Previous investigations of canine inflammatory conditions and models of endotoxemia demonstrated a significant decrease in the MPC, consistent with platelet activation. The purpose of this study was to evaluate the MPC and other platelet parameters in dogs with different diseases to determine if they could show differential platelet activation with different pathologies. The hypothesis was that the MPC would decrease in clinical conditions associated with systemic inflammation or platelet activation. Complete blood counts run on the analyzer from dogs with different inflammatory conditions (primary immune-mediated hemolytic anemia (IMHA) or thrombocytopenia (ITP), pituitary-dependent hyperadrenocorticism, intra-abdominal sepsis, pancreatitis, intravascular thrombus or thromboembolus and hemangiosarcoma) were reviewed retrospectively and compared with those of control dogs presenting for orthopedic evaluation. Dogs with ITP had a decreased plateletcrit and MPC, with an increased platelet volume and number of large platelets (P < 0.001). Dogs with IMHA had an increased plateletcrit and mass, and more numerous large platelets (P < 0.001).With the exception of the ITP group, there was no difference in MPC in the diseased groups when compared with the controls. The results of this study suggest the MPC does not change in certain canine diseases associated with systemic inflammation.