Processing of donated blood
Blood is a complex fluid consisting of different blood cells suspended in yellowish liquid called plasma. The blood cells comprise a mixture of red cells (erythrocytes), white cells (leukocytes) and platelets (thrombocytes). The plasma contains water, chemical substances (electrolytes), many different proteins such as clotting (coagulation) factors and immunoglobulins and numerous metabolic substances. Blood serves as a transport medium for carrying all its different components to and from the different organs of the body.
Blood collected in an anticoagulant can be stored and transfused to a patient in an unmodified state. This is known as ‘whole blood’ transfusion. Blood may be used more effectively if component therapy is practised. One unit of donated blood may be divided into components, including red cells concentrates, fresh frozen plasma, cryoprecipitates and platelet concentrates, to meet the needs of more than one patient.
Advantages of component therapy are:
- the recipient can be treated with only those blood components that are lacking, reducing the occurrence of adverse transfusion reactions;
- more than one patient can be treated with blood components derived from one donation;
- therapeutic support for patients with special transfusion requirements can be provided, for example, plasma that often is not directly needed for transfusion can be used manufacturing of Factor VIII concentrate for Haemophilia A patients;
- improved quality and functional capacity of each components when varied storage conditions and shelf lives were applied.
For a safe and effective blood component processing, the following elements are required:
- Commitment and support by national health authorities for a sustainable, well-organised, nationally co-ordinated blood transfusion service, with adequate resources and quality system for all areas;
- Centralisation of blood processing and testing within major centres to permit economies of scale by maximising utilisation of personnel and equipment and uniform standards;
- Reliable supply of materials and consumables;
- Well-maintained equipment and spares available to keep down-time to a minimum;
- Effective and timely testing of all donated blood to ensure maximum safety and availability of blood components;
- A system for appropriate storage and transportation to ensure quality and efficacy of blood and blood components;
- Optimisation of the use of plasma for fractionation where facilities are available;
- Promotion of appropriate blood component therapy.