Fresh frozen plasma (FFP) is separated and frozen, usually within six to eight hours after collection, to preserve factor VIII content. Other plasma components are:
- Cryoprecipitate – this is prepared by controlled thawing of frozen plasma to precipitate high molecular weight proteins, including factor VIIIc, von Willebrand factor and fibrinogen
- Cryoprecipitate depleted plasma – this is FFP from which cryoprecipitate has been prepared, leading to reduced concentration of fibrinogen and factor VIII
Removal of leucocytes to a level of less than one million per component by filtration or during collection of blood components by apheresis is normal practice in a number of EU countries.
Advantages of leucodepletion include a marked reduction in alloimmunisation to HLA antigens and in the risk of infection by intracellular viruses such as cytomegalovirus. Leucodepletion of red cells may also be associated with improved outcomes in some groups of patients.