Utility of DRG and ICD‐9‐CM classification codes for the study of transfusion issues

Red cell transfusions in all patients within specific medical or surgical diagnosis-related groups (DRGs) and International Classification of Diseases (ICD-9-CM) classes were analyzed by a unique body of data that combined abstracted patient discharge records with the numbers of red cell units transfused. Informative measures of transfusion practice within an ICD-9-CM class were the proportion of patients transfused, the mean units transfused per patient, and the ratio of standard deviation to the mean of units transfused. Transfusion frequency plots (percentage of patients against units of red cells transfused per patient) revealed the existence of a modal transfusion frequency, as well as an asymmetric tail on the high frequency side. These and other features make it possible to characterize transfusion practice in specific ICD-9-CM classes. The mean units of red cells transfused for all patients in a DRG is a measure of blood resource utilization and should be useful in planning to meet future needs.