Preselection of donors to improve the quality of cryoprecipitate

Stability of von Willebrand factor and factor VIII in canine cryoprecipitate under various conditions of storage

The stability of factor VIII and von Willebrand factor antigen in canine cryoprecipitate obtained from seven greyhound donors was determined after storage under various conditions, including twice freezing at -70 degrees C and thawing at 37 degrees C, slow thawing at 4 degrees C, refreezing the slowly thawed cryoprecipitate at -20 degrees C and thawing at 37 degrees C and maintaining the thawed cryoprecipitate at room temperature for 24 hours. The results indicated that factor VIII and von Willebrand factor antigen were effectively concentrated during the initial cryoprecipitation procedure. The cryoprecipitate which had been thawed and refrozen under the above conditions maintained factor VIII activities and concentrations of von Willebrand factor antigen similar to those in the original thawed cryoprecipitate. Furthermore, there was no significant loss of either of the coagulation factors in cryoprecipitate which was thawed in a warm water bath and stored for 24 hours at room temperature.

Cryoprecipitated antihemophilic factor production from blood collected in quad packs or from blood with delayed processing. The importance of plasma thawing method

Two alternate approaches to increasing the supply of plasma suitable for the production of cryoprecipitated AHF (cryo) were evaluated. In the first, cryo was prepared from blood collected in quadruple packs from which red cells and platelets also were made. This procedure resulted in a mean reduction of starting plasma volume of about 25 percent with a concomitant decrease in factor VIII coagulant activity (FVIII:C) of cryo when compared to approximately 2000 cryos made in triple packs assayed in our laboratory during the past year. However, American Red Cross (ARC) regions using a higher yield waterbath method of thawing plasma successfully produced quadruple pack cryos with a mean potency of 109 international units per container and about 90 percent of them met federal potency requirements. This was not the case for ARC regions using the lower yield method of thawing plasma in a refrigerator. The second approach involved cryo production from plasma frozen following 15 hours of cold storage of either the separated plasma or whole blood. Cold storage of plasma resulted in small but insignificant decreases in FVIII:C potency and yield in the cryo. However, there was a 20 percent decrease in FVIII:C yield in cryo produced from frozen plasma following 15 hours of cold storage of whole blood. Again, the decrease in FVIII:C yield resulting from interim blood storage was compensated for by the use of the higher yield waterbath method.