Blood components are those products derived from whole blood (or platelet-rich plasma) collected from normal donors by phlebotomy (or hemapheresis) using the technique of differential centrifugation. These products are prepared in blood centers or hospital laboratories, and should be distinguished from plasma derivatives, which are fractionated from large volumes (thousands of liters) of plasma in large, industrial manufacturing sites.
This topic review will discuss the preparation of blood components. Use of these blood components is discussed separately. (See "Clinical use of plasma components".)
The manufacture of plasma derivatives and their general use is discussed separately. (See "Plasma derivatives and recombinant DNA-produced coagulation factors" and "Pathogen inactivation of blood products".)
The components of whole blood (ie, plasma, cryoprecipitate, red cells, lymphocytes, granulocytes, platelets) have different requirements for optimum storage and preservation of function. As examples:
- Platelets left in units of red cells at refrigerator temperatures clump and interact with red cells and plasma proteins, and rapidly lose hemostatic effectiveness and/or are removed by filtration during transfusion.
- Coagulation factors, especially factors V and VIII, are somewhat labile even at 4ºC.