Читать книгу Transfusion Medicine - Jeffrey McCullough - Страница 140

Coagulation factor VIII is a cold insoluble protein [61]. Pool and Shannon [62] took advantage of this to develop a method to recover most of the factor VIII from a unit of WB in a concentrated form. Cryoprecipitate is the cold insoluble portion of FFP that has been thawed between 1°C and 6°C. The cold insoluble material is separated from the thawed plasma at 1–6°C immediately and refrozen within 1 hour. Although there are no specific requirements for the volume of a unit of cryoprecipitate, it is usually 5 mL or more, but less than 10 mL. The cryoprecipitate units must contain at least 80 units of factor VIII and 150 mg of fibrinogen [24]. Cryoprecipitate is not a suitable source of coagulation factors II, V, VII, IX, X, XI, and XII [63]. Several factors influence the content of factor VIII in cryoprecipitate, including the blood group of the donor (group A is higher than group O), the anticoagulant (CPD is higher than acid–citrate–dextrose), the age of the plasma when frozen, and the speed of thawing the FFP [64]. Cryoprecipitate also contains fibrinogen and von Willebrand factor, and with the availability of coagulation factor concentrates these are the primary uses of cryoprecipitate. Each bag of cryoprecipitate contains about 250 mg of fibrinogen [63]. Cryoprecipitate is stored at −18°C or below and can be kept for up to 1 year.