Studies on the procurement of blood coagulation factor VIII: effects of plasma freezing rate and storage conditions on cryoprecipitate quality.

Plasma was frozen and stored in different ways before processing to cryoprecipitate by a standard thawing technique. Freezing rate was found to be important with slow freezing having a deleterious effect on cryoprecipitate quality. Storage of frozen plasma at constant temperatures for periods up to six months had no effect on the quality of cryoprecipitate, with no difference being found for plasma stored at -20 degrees C or -40 degrees C. Subjecting frozen plasma to deliberate temperature fluctuations resulted in a considerable increase in the amount of fibrinogen recovered in cryoprecipitate, with the factor VIII yield being relatively unaffected.