Whole blood, the blood you give during donation, is rarely used in its donated state. Whole blood is only used in the case of severe blood loss due to surgery, trauma or for exchange transfusion in infants.
Blood is mostly transfused in its main constituent parts: plasma, platelets and red cells. This means that one unit of blood (a single blood donation of 475ml) can potentially save up to three lives. Impressive, isn’t it?
Before transfusion, and after rigorous processing at the blood bank, donor and recipient blood must be matched according to their respective types. From there, constituents are used as follows:
- Red blood cells are used to replace losses as a result of accidents, trauma, childbirth and surgery, as well as for burn victims. They are also essential in the treatment of various kinds of anaemia linked to cancer and rheumatoid arthritis, as well as sickle cell anaemia. These essential cells must be used within 42 days of donation if fresh, but can also be frozen for longer periods.
- Plasma is the liquid component of blood that contains essential nutrients and proteins. It is used primarily as a source for clotting factors, the replacement of blood volume and the production of albumin, a protein used to treat severe shock, burns and blood loss. Fresh frozen plasma has a shelf life of one year and is used during cardiac surgery and childbirth.
- Cryoprecipitate is a small portion of plasma that is harvested using a freeze-thaw process. It contains factors to help blood clot and is used primarily as a source of clotting factor VIII for patients with classic haemophilia.
- Stabilised human serum is used for the treatment of burn wounds and hypovolaemia (decreased blood volume).
- Platelets help blood clot and are used to treat patients with bone marrow production problems, and in the treatment of illnesses such as leukaemia. Platelets must be harvested within eight hours of donation and are stored at room temperature in a gently agitated state so as to be functional when transfused. They must be used within five days of donation.