Complex technical, administrative, and clinical steps involving multiple staff members and various materials and other resources must be successfully completed for a blood transfusion to be given and properly managed. These factors are responsible for the direct and indirect costs of transfusion, which are often overlooked and vastly underestimated. In this study, the total cost of red blood cell (RBC) transfusion process in the surgical setting was calculated through activity-based costing (ABC) in a US hospital as a part of the Cost-of-Blood Consensus Conference (COBCON) project, sponsored by the Society for the Advancement of Blood Management (SABM; Shander et al, Transfus Med Rev. 2005; 19:66–78). Initially, main transfusion-related processes were identified by observing the “passage” of blood units (from ordering at local blood services to discarding empty bags and expired units) and recipients (for all major pre-, intra- and post-transfusion-related routines performed) through the system. Then, each main process was broken down into serial and parallel activity steps and the frequency (usage factor) and all required resources for each activity were determined. Local cost rates for all resources were retrieved. Specifically developed ABC software modules developed by Medizinische Gesellschaft für Blutmanagement, Laxenburg, Austria in collaboration with IDS-Scheer AG, Germany, based on ARIS Business Architect 7.02 (IDS-Scheer AG, Germany) were used to calculate the cost of each main transfusion process based on these data. Individual processes were condensed, multiplied by usage factor and flow-charted into the total transfusion process, generating the database for hospital's total process cost of transfusion. Direct and indirect overhead costs were also calculated and added. All data were validated by appropriate hospital personnel. In 2005, 2413 surgical patients were prepared for potential transfusion, of whom, 461 patients received a total of 1368 blood units (2.97 blood units per surgical patient; 1121 units transfused in ward, 132 in intensive care unit, 69 in operating room/post-anesthesia care unit and 46 in emergency room). RBC units were ordered and transported in bulk from blood services 156 times. Transfusion-related processes with highest usage factor for performing these 461 transfusions are listed in the table. A total of 21 mild or moderate and no severe transfusion reactions were reported. There was no transfusion-related litigation or patient reimbursement due to transfusion errors or complications in the studied period. Based on these data, the total cost of RBC transfusion per patient transfused in the surgical setting of this hospital was US$ 3433. The total cost of a unit of RBC was US$ 1,158 (2007 value), of which, indirect overhead, total transfusion process cost, weighted average acquisition cost and direct overhead cost per unit accounted for 40.6%, 34.0%, 21.5% and 3.9%, respectively. This study shows that the true cost of blood transfusion is much higher than the nominal value currently assigned to each unit of blood.Table: Transfusion-related processes with highest usage factor in surgical setting. Not all processes are listed.Main processesUsage factor/frequencyExplaining transfusion risk and obtaining informed consent13,233Pre-transfusion examination & clerical routine>2,413Phlebotomzig & delivering patient's blood specimen to blood bank & central lab>2,485Patient blood testing in central lab & analyzing results - routine & emergency>2,413Controlling & storing components in hospital blood bank1,445ABO/Rh-typing new patients>1,330ABO/Rh-typing control>2,413Antibody screening>2,413Cross matching4,028manual distribution of components and controlling delivery received at transfusion site1779Return deliveries of unused components633Cleaning transfusion site & disposing waste>455Administering and monitoring transfusion1368