The algorithm used to derive the maximum surgical blood order schedule. The thresholds in the algorithm for percentage of patients transfused, median estimated blood loss (EBL), and transfusion index (mean number erythrocyte units transfused per patient) are derived from previous studies.^11,13–15  “Risk of major bleeding” was determined to be “yes” or “no” for each surgical procedure category based on the proximity of the surgical field to large vascular structures. RBC = erythrocytes; U = units.