ICD-9: Understanding the International Classification of Diseases (9th Revision)

The abbreviation ICD9 stands for the International Classification of Diseases, 9th Revision. It is a system of codes used to classify diseases and conditions for statistical purposes. It was developed by the World Health Organization (WHO) and is used in many countries around the world, including the United States. The ICD9 system has been replaced by the ICD10 system, which was released in 2015.