This is a universal measure to remove granulocytes and lymphocytes from the blood prior to storage. Australian PRBCs are now routinely leukodepleted. In the olden days, one would run the undepleted PRBCs through a filter at the bedside.
Some believe that there is a good reason we spend money on this practice, even though there is no evidence to support the "extended indications" for leukoreduction.
Specifics of this issue were discussed in Question 29.2 from the first paper of 2010.
Prior to the introduction of universal leukoreduction, there were groups of patients who were known to benefit from such products. The hard indications for leukoreduced blood products are as follows:
Currently, there is no evidence that the practice of routinely leukoreducing all packed RBCs is improving mortality and morbidity. Certainly, there is no evidence that the practice has any influence on mortality outside of its narrow range of indications. This has prompted some people to question whether this practice is a cost-effective public health measure. And others to question whether the reintoduction of nondepleted products would result in some sort of haematological apocalypse.
Goodnough, Lawrence T., Jerrold H. Levy, and Michael F. Murphy. "Concepts of blood transfusion in adults." The Lancet 381.9880 (2013): 1845-1854.
Spahn, Donat R., and Lawrence T. Goodnough. "Alternatives to blood transfusion." The Lancet 381.9880 (2013): 1855-1865.
There is also a rescinded document from the NHMRC (2001) which has been used to guide practice: Clinical Practice Guidelines on the Use of Blood Components.
To some extent this document has been superceded by the Australian and New Zealand Society of Blood Transfusion GUIDELINES FOR THE ADMINISTRATION OF BLOOD PRODUCTS.
The Patient Blood Management Guidelines from the National Blood Authority of Australia is another series of documents worth looking at - it contains several important modules which have been reviewed and which act as successors to the 2001 NHMRC guidelines.
Treleaven, Jennie, et al. "Guidelines on the use of irradiated blood components prepared by the British Committee for Standards in Haematology blood transfusion task force." British Journal of Haematology 152.1 (2011): 35-51.
Aoun, Elie, et al. "Transfusion‐associated GVHD: 10 years’ experience at the American University of Beirut—Medical Center." Transfusion 43.12 (2003): 1672-1676.
Heddle, Nancy M., and Morris A. Blajchman. "The leukodepletion of cellular blood products in the prevention of HLA-alloimmunization and refractoriness to allogeneic platelet transfusions [editorial]." Blood 85.3 (1995): 603-606.
Sharma, R. R., and Neelam Marwaha. "Leukoreduced blood components: Advantages and strategies for its implementation in developing countries."Asian journal of transfusion science 4.1 (2010): 3.
Dzik, Walter H. "Leukoreduction of blood components." Current opinion in hematology 9.6 (2002): 521-526.
Corwin, Howard L., and James P. AuBuchon. "Is leukoreduction of blood components for everyone?." JAMA 289.15 (2003): 1993-1995.
Blajchman, M. A. "The clinical benefits of the leukoreduction of blood products."Journal of Trauma-Injury, Infection, and Critical Care 60.6 (2006): S83-S90.
Rosenbaum, Lizabeth, et al. "The reintroduction of nonleukoreduced blood: would patients and clinicians agree?." Transfusion 51.12 (2011): 2739-2743.
Bilgin, Y. M., L. M. van de Watering, and A. Brand. "Clinical effects of leucoreduction of blood transfusions." Neth J Med 69.10 (2011): 441-450.
Australian Red Cross - Blood Service Policy on "The Age of Red Cells"
Hess, John R. "Red cell changes during storage." Transfusion and Apheresis Science 43.1 (2010): 51-59.
Bennett-Guerrero, Elliott, et al. "Evolution of adverse changes in stored RBCs."Proceedings of the National Academy of Sciences 104.43 (2007): 17063-17068.