Mean platelet component as an indicator of platelet activation in foals and adult horses

Background: Mean platelet component (MPC) is a new platelet variable, measured by modern commercial complete blood count analyzers, that is reduced during platelet activation in humans and small animals. Hypothesis: MPC decreases in horses with clinical conditions that cause platelet activation and disseminated intravascular coagulation (DIC). Animals: We obtained 418 CBCs from 100 sick and 20 healthy neonates and 178 sick and 45 sound adult horses. Sick neonates were classified into septic and nonseptic, and DIC and non-DIC groups. Adults were grouped by diagnoses (systemic inflammatory disorders, gastrointestinal problems, and thrombocytopenia). Methods: MPC together with platelet count, mean platelet volume, platelet distribution width, and platelet component distribution width were measured with a commercial analyzer and compared between the different disease and control groups in neonates and in adults. Results: MPC values were significantly lower in the septic and nonseptic neonates (24.0 ± 3.5 g/dL and 26.6 ± 2.6 g/dL, respectively) than in the control group (28.1 ± 1.7 g/dL). Neonates with DIC had the lowest MPC values (23.8 ± 6.3 g/dL). MPC values in adult horses were significantly lower in the inflammatory (23.5 ± 4.7 g/dL), gastrointestinal obstruction (23.0 ± 5.0 g/dL), enteritis (23.6 ± 4.6 g/dL), ischemic (23.9 ± 5.1 g/dL), and thrombocytopenia (20.2 ± 5.7 g/dL) groups when compared with control horses (26.2 ± 3.5 g/dL). Other platelet variables were not different between the control and the disease groups. Conclusion and Clinical Importance: MPC might be a useful variable for quickly and easily detecting platelet activation in sick neonates and adult horses.