Methods of assessing factor VIII content of stored fresh frozen plasma intended for preparation of factor VIII concentrates.

Minimally destructive methods were sought to assess the factor VIII content of fresh frozen plasma intended for large-scale fractionation and stored in five-liter polyethylene packs after pooling approximately 23 plasma donations. Although factor VII distribution in the frozen pack was not perfectly homogenous, a central "core" through the frozen pack gave a representative sampel of the entire contents of the pack. Coring was compared with other methods of pack sampling before large-scale cryoprecipitation. The survival of factor VIII was studied in three grades of stored plasma which had been separated and frozen within 4 hours, 8 hours, and 18 hours of blood donation. Plasma frozen after overnight storage of blood is a satisfacory starting material for the preparation of factor VIII and factor IX concentrates.