Stability of canine factor VIII activity and von Willebrand factor antigen concentration in vitro

Abstract

The in vitro stability of canine factor VIII activity, von Willebrand factor antigen concentration and the ratio of these two factors was studied. Samples were stored for up to 48 hours, either as plasma or as whole blood, at 4°, 20° and 37°C. Factor VIII activity was generally stable in both plasma and whole blood samples for up to 48 hours at 4° or 20°C. The concentration of von Willebrand factor antigen was more stable in samples stored as plasma than whole blood, and for a shorter time than factor VIII activity. Consequently, the stability of the ratio of these two factors was relatively poor in vitro. © 1991.