Olusanya  (Olusanya 2015) proposed an efficient new method by combining different techniques, the queue and particle swarm optimisation (PSO) with multiple knapsack problem to address the challenges accompanying the BAP. The PSO, multiple knapsack assignment method which is used to handle the cross-matching of blood types to satisfy the requested units and stabilise the stored blood types in the bank, whereas queuing technique was used to monitor the expiration date of each blood type. The objective was to optimise the assignment of blood types and minimise wasted units and importation from external sources which could be very expensive. By using the above techniques, the total number of blood units imported from external resources were significantly minimised with no wastage.