A Statistical Approach to Ordering and Usage Policies for a Hospital Blood Bank*

An electronic computer (UNIVAC 1105) is used in a simulation study to determine ordering and usage policies for a hospital blood bank. It is assumed that only type specific transfusions are given, and all use of fresh blood obtained for specific cases is excluded. A ratio of 25:4 is taken as the ratio of the cost whenever the bank is “short” of a unit for actual transfusion to the cost of an outdated unit. Optimal inventory levels are determined for a particular bank when the oldest blood is used first and the random volunteer donor input is maintained at current levels, when this input is doubled, and when the entire input is composed of ordered blood having life of 15 days. If the random input is doubled the losses are almost quadrupled. The losses would be least if the input were completely ordered and the life of the ordered blood were not restricted; but when the ordered blood has a life of only 15 days the losses are somewhat higher than when the random input remains unchanged. Consequences of always using the freshest blood first are also examined. This policy does not appear to be feasible unless the bank contains an excessive amount of blood.