Comparison of equine platelet function and survival in whole blood collected in acid-citrate-dextrose solution or citrate-phosphate-dextrose-adenine solution

Background: Equine whole blood collection and storage methods have been evaluated to assess red blood cell viability; however, platelet (PLT) viability has not been comprehensively assessed. Objectives: The purpose of the study was to compare viability of PLTs collected in whole blood into 2 different anticoagulants. Methods: Whole blood from 6 healthy adult Thoroughbred horses was collected into citrate-phosphate-dextrose-adenine (CPDA) or acid-citrate-dextrose (ACD). Platelet count, pH, and concentrations of glucose, lactate, carbon dioxide, oxygen, bicarbonate, sodium, potassium, and chloride were measured within 10 minutes of collection and then again one hour later at which time PLT aggregometry was performed to assess PLT function. Results: Aggregometry mean amplitudes were significantly higher in CPDA compared to ACD. Blood glucose, pH, bicarbonate, sodium, and lactate concentrations were significantly higher in CPDA compared to ACD. Lactate concentration was higher following one hour in either anticoagulant. Potassium, oxygen, and carbon dioxide concentrations were significantly higher in ACD compared to CPDA at collection. Conclusions: Platelet aggregometry results suggest that CPDA is superior to ACD for maintaining PLT viability following whole blood collection. This may be associated with the higher, more neutral pH as well as an increase in glucose available for metabolism. Although lactate was increased in the CPDA samples it was not high enough to decrease pH and therefore may not have been high enough to cause morphologic lesions and loss of PLT viability.