Should autologous blood that tests positive for infectious diseases be used or discarded? A decision analysis approach.

Decision analysis was applied to the question of whether to keep or discard autologous blood donations that test positive for viral markers. The decision is reached by analyzing a series of different events that lead to different outcomes. The probability of each event must be estimated and a value ("utility") assigned to specific outcomes. The underlying assumptions of the analysis are reviewed. After assigning a probability to each event and a utility to each outcome, one can compute a probability (P*) that is compared to the likelihood that the autologous donor will need transfusion. If the probability of transfusion exceeds P*, then keeping the infectious unit is favored. Otherwise, discarding the infectious unit is preferred. The analysis argues against a single, uniform national policy regarding the disposition of infectious autologous units. The method outlined provides a rational basis for setting policy regarding a controversial issue in Transfusion Medicine.