Stability of Hemostatic Activity in Leukoreduced and Non-Leukoreduced Canine Plasma Units Stored Refrigerated or Frozen for 7 Days After Collection

Plasma products are a fundamental treatment for domestic animals with hemorrhage due to coagulation factor deficiency. To preserve hemostatic activity, plasma units are stored frozen at -20°C or colder. A major limiting factor in using frozen plasma is the time required to thaw plasma products. This study evaluated activity of specific coagulation factors in fresh plasma units stored for 7 days at 4-6 C° compared to frozen plasma units. In addition, effect of leukoreduction on factor activity was evaluated. In a prospective, laboratory in vitro study, 200 ml WB units were collected using specific canine collection systems (TEC 710 and TEC 709 Futurlab®) from ten healthy Golden Retrievers. Five WB units were non-leukoreduced and five were leukoreduced before centrifugation. Plasma units were obtained within 6 hours of blood collection by centrifugation and were aliquoted into two 50 ml plasma units and stored: at 4-6°C or frozen at -20°C. All units were analyzed at collection (D0) and after 7 days (D7). Coagulation factors evaluated were: FATIII, FV, FVIII, FX, FXI, von Willebrand (FvW) using STACompact Max® analyzer (Diagnostica Stago). The protocol was approved by the University of Milan Animal Welfare Bioethical Committee (OPBA_26_2018). Results from refrigerated and frozen plasma units were statistically compared with statistical significance set at P<0.05. Effect of leukoreduction was also evaluated. Significant reduction in FVIII and FvW was found in refrigerated compared to frozen units at D7 (mean difference -38.9%, P=0.001 and -22.6%, P=0.002, respectively). Mean factor activities in refrigerated plasma were >50% D0, with the exception for FvW (mean value in D7 refrigerated plasma units: 47.5%). There was no significant effect of leukoreduction other than on FXI activity, which was significant lower (P<0.001) and with mean values <50% in leukoreduced compared to non-leukoreduced plasma units at D0. Plasma separated within 6 hours of blood collection and stored at 4-6°C for 7 days had coagulation factor activity comparable to plasma units stored frozen at -20°C. The exception being FvW, where activity >50% was only seen in frozen plasma. Leukoreduction only significantly affects activity of FXI plasma coagulation factor.