The risks and costs associated with the transfusion of blood and its components have led to increasing demands for evidence of the appropriate use of blood components. We have examined the use of packed red blood cells (PRBC) in association with seven common, surgical procedures performed in 1987 and 1988 to establish patterns of use. The information has formed the basis for surgical blood order schedules and autologous donation targets for these procedures. It has also been used to determine appropriate audit 'triggers' and the results of an audit using these 'triggers' are reported.