Storing Crossmatched Blood: A Perishable Inventory Model with Prior Allocation

The process of testing a sample of a patient's blood against units of blood from inventory to ensure compatibility is called crossmatching. When a physician orders blood, it is crossmatched and then held for a patient. As a precautionary measure, physicians tend to order blood in excess of the amount that is transfused (used by the patient). Consequently, a large proportion of blood held for a patient (often higher than 50 percent) is eventually not transfused. This leads to increased outdates. The effects of crossmatching on outdates are widely acknowledged, but have seldom been included in blood inventory control models. In this paper, we develop a model for determining outdates and shortages for crossmatched blood using generally accepted parameters, such as proportion of crossmatched blood that is actually transfused, and the number of days after which crossmatched blood is released if not transfused. This model can be used as a decision support system that allows the blood bank administrator to do sensitivity analyses related to controllable blood inventory parameters.