Target inventory levels for a hospital blood bank or a decentralized regional blood banking system.

For any blood type, there is a complex interaction among the optimal inventory level, daily demand level, the transfusion to crossmatch ratio, the crossmatch release period and the age of arriving units that determine the shortage and outdate rate. The blood bank administrator should establish optimal target inventory levels based on a simple equation (decision rule) relating these factors. Evaluation of this rule indicates that its implementation can lead to a very low shortage rate and a reasonable low outdate rate if the blood bank administrator makes efforts to control the crossmatch release period and the average transfusion to crossmatch ratio.