For many important aspects of transfusion practice, there is not a firm basis of empirical evidence that identifies the most effective process or treatment. Ideally this would be derived from well conducted, randomised, controlled clinical trials. As a result, many accepted procedures and clinical transfusion guidelines are based on the best available information and evidence, such as observational studies, case reports or professional consensus. The Transfusion section of the site provides an illustration of evidence-based practice recommendations with extracts from the 2009 German haemotherapy guidelines. (Download at the bottom of the page).

In addition, the web version of the manual provides links to the underpinning evidence where there is high quality information as judged by established grading systems. An extensive database of clinical trials and systematic reviews of evidence relating to transfusion can be found at www.transfusionguidelines.org.uk.

Evidence about common procedures in the clinical transfusion process is extremely limited and is reviewed in: PMID 18399846, 19302450 and 18194372.