Platelets and factor VIII as functions of blood collection time

Plasma and platelet concentrates were prepared from whole blood collected in less than eight minutes, and from blood collected in 8 to 12 minutes. Comparison was made between the two collection groups of Factor VIII activity in fresh plasma, and of Factor VIII activity in fresh frozen plasma. Using the rank sum test, no significant difference was found between Factor VIII activities in either fresh or fresh frozen plasma. The number of platelets in concentrates prepared from blood collected in less than eight minutes were compared with those in concentrates from blood collected in 8 to 12 minutes. Mean numbers of platelets were 6.89 x 10(10) and 7.12 x 10(10),respectively. No significant difference was found between the two groups when compared by the rank sum test, or the "t" test. Current guidelines recommending maximum eight-minute collection for component preparation may be inappropriately restrictive.