Appendix B Transfusion risks in the context of patient blood management

Traditionally, it has been assumed that blood transfusion benefits patients; however, a benefit has not been demonstrable in many clinical scenarios. In addition, evidence is accumulating that serious non- viral adverse events, such as transfusion-associated circulatory overload (TACO) or transfusion-related acute lung injury (TRALI), are more common than previously thought, and that more recently identified conditions (e.g. transfusion-related immunomodulation) may cause patients harm.

The risk of transmission of infectious diseases through blood transfusions has reduced significantly in recent years, through improved manufacturing and laboratory processes. However, there is potential for transfusion of an unrecognised infectious agent.

Despite improvements in systems management, there remains a risk of transfusion-related harm due to administrative error. Such an error has the potential to result in acute haemolytic reaction from ABO incompatibility, which may be fatal.

If the patient requires therapy for anaemia, thrombocytopaenia or coagulopathy, transfusion should not be a default decision. Instead, the decision on whether to transfuse should be carefully considered, and should:

In the process of obtaining informed consent, a clinician should allow the patient sufficient time to ask questions, and should answer those questions. If the patient is unable to speak or understand English, the clinician may need to involve an interpreter. In certain contexts, a trained medical interpreter may be required (rather than a family member or a friend). Written information and diagrams may be appropriate in certain circumstances to aid understanding.

All elements of the consent process should reflect local state, territory or national requirements.

Table B.1 summarises transfusion risks, and Table B.2 presents the Calman Chart, which may be useful to clinicians for explaining risks to patients.177

Table B.1 Transfusion risks
Transfusion-associated circulatory overload (iatrogenic) Up to 1 in 100 transfusions High
Transfusion-related acute lung injury 1 in 1200 – 190,000 Low to minimal
Haemolytic reactions Delayed: 1 in 2500 – 11,000
Acute: 1 in 76,000
Fatal: Less than 1 in 1 million
Low to very low
Very low
Anaphylactoid reactions or anaphylaxis (usually due to IgA deficiency) 1 in 20,000 – 50,000 Very low
Bacterial sepsis: platelets 1 in 75,000 Very low
Bacterial sepsis: red blood cells 1 in 500,000 Minimal
Hepatitis B Less than 1 in 1 million Negligible
Hepatitis C Less than 1 in 1 million Negligible
Human immunodeficiency virus Less than 1 in 1 million Negligible
Human T-lymphotropic virus (types 1 and 2) Less than 1 in 1 million Negligible
Malaria Less than 1 in 1 million Negligible
Variant Creutzfeldt-Jakob disease (not tested) Never reported in Australia Negligible
Transfusion-associated graft-versus-host disease Rare Negligible
Transfusion-related immunomodulation Not quantified Unknown

a Risk per unit transfused unless otherwise specified

b See Calman 1996177

Source: Australian Red Cross Blood Service website (

Note: The above estimates may change over time. Refer to the Australian Red Cross Blood Service website ( for the most recent risk estimates.

Table B.2 Calman Charta (United Kingdom risk per one year)
Negligible <1 in 1,000,000 Death from lightning strike
Minimal 1 in 100,000 – 1,000,000 Death from train accident
Very low 1 in 10,000 – 100,000 Death from an accident at work
Low 1 in 1,000 – 10,000 Death from a road accident
High >1 in 1,000 Transmission of chicken pox to susceptible household contacts

a See Calman 1996177