A framework for applying the precautionary principle to transfusion safety.

The precautionary principle has become highly influential in the formation of policies concerning transfusion safety. The adoption of the principle to address theoretical risks has resulted in highly risk averse policy which has both enhanced the safety of the blood supply but also contributed to rising blood costs. The application of the precautionary principle to transfusion medicine has presented some challenges including clearly defining the principle and recognizing that the application of precaution can itself create risks to health by reducing the donor supply. This article provides a guide to applying precaution to matters of transfusion safety. Types of risk-based decision-making can be classified as strong, intermediate/weak, or no precaution by determining the strength of evidence required to apply a protective measure and the extent of the protective measure applied. The decision on what type of precaution to implement can then be determined based on the response to the following questions for a given transfusion safety matter: (1) Is the extent of the exposure large? (2) Is the consequence of the exposure serious? (3) Is the consequence of the exposure irreversible? (4) Is there minimal cost associated with the removal of the exposure? (5) Is there a minimal negative health effect associated with removing the exposure? Using this approach can help standardize the approach to applying precaution in transfusion safety.