International Classification of Diseases ninth revision (ICD-9)
ICD-9-CM is a medical code set maintained by the World Health Organization (WHO). The primary purpose of this code set is to classify causes of death. It is a U.S. extension, maintained by the National Center for Health Statistics within the Centers for Disease Control and Prevention (CDC), that identifies morbidity factors or diagnoses. The ICD-9-CM (clinical modification) codes have been selected for use in HIPAA transactions.