Informed consent for blood transfusion: should the possibility of prion risk be included?

The emergence of bovine spongiform encephalopathy (BSE) in British cattle has received significant media attention since its discovery in 1986. Transmission of this prion from cattle to humans has been documented, and the BSE prion is believed to be the causative agent for variant Creutzfeldt-Jakob disease (vCJD). Evidence of this spread is a significant threat to public health, and, although there has never been a proven case, there is a theoretical risk of transmission between humans by blood transfusions. In addition, recent animal studies have documented spread in this fashion, raising the question of whether vCJD should be included as part of informed consent for blood transfusions. The process of informed consent requires disclosure of material risks, defined as the risks that a reasonable person, under such circumstances, would want to know. Consent should, therefore, include the risks of a transfusion reaction, as well as the known infectious risks of blood. It should also include the unknown or theoretical risks of blood transfusions because full disclosure of even remote risks preserves the patient/physician trust relationship, which if breached, is very difficult to mend. Given the high level of public awareness, the potential lethality of the infection, and the theoretical risk of transmission by blood, vCJD can be considered a material risk, and consequently, it is reasonable to include it in the informed consent process.