In each inventory management model, several assumptions are to be made. Osorio and Brailsford (Osorio 2016) proposed an integrated simulation-optimisation model to support strategic and operational decision making. They used an integer linear optimisation model to run over a planning horizon; it was used to support daily decision such as target number of donors, collection methods, and production planning. A discrete event simulation (DES) were then used to represent flows through the supply chain. In this way, the model can be used in two modes: strategic level to help blood bank managers to evaluate unique resources, allocation policies, and at operational level to set daily collection and production targets. The model output of both cases is considered as standard key performance indicators: stockouts, outdoes, several donors, and production costs.