Stability of Factors V and VIII in Thawed Fresh Frozen Plasma Units

Abstract

Factors V and VIII, commonly regarded as unstable in unfrozen plasma, were assayed at various intervals up to 24 h using [human] plasma from 20 thawed fresh-frozen plasma (FFP) units. Comparisons were made between units stored at 4 and 25.degree. C. The mean factor V value did not significantly change during the postthaw test period. Mean factor VIII activity prior to freezing was 121%, dropped to 89% 4 h after thawing, and gradually decreased to 67% at 24 h. There was no difference between those units stored at 4.degree. C and those stored at 25.degree. C after thawing; refrigeration does not appear necessary for factor V or VIII stability up to 24 h after thawing.