The ICD is currently the most widely used statistical classification system for diseases in the world. ICD-9-CM is an adaption created by the U.S. National Center for Health Statistics (NCHS) and used in assigning diagnostic and procedure codes associated with inpatient, outpatient, and physician office utilization in the United States.

The ICD-9-CM is based on the ICD-9, but provides for additional morbidity detail.