In the United States, the ICD-9-CM is a system used in health care and hospitals to assign codes to different medical procedures and diagnoses for purposes such as billing and updating a patient's electronic records. The letters ICD-9-CM stand for International Classification of Diseases, ninth revision, clinical modification. These codes were adapted from the codes ICD-9, which were established by the World Health Organization (WHO) in 1978 to keep track of mortality statistics, as noted by the U.S. Centers for Disease Control and Prevention.
The ICD-9 codes established by WHO were in effect until 1999, when the updated version coding system ICD-10 began. Similarly, ICD-10-CM is the new revision for the ICD-9-CM system used in billing, as noted by the Medical Billing & Coding Certification website.
The government agencies, which are in charge of modifying the ICD-9-CM code system, are the National Center for Health Statistics and the Center for Medicare and Medicaid Services. The ICD-9-CM system used for billing purposes is made of a numerical list, disease index in alphabetical order and the classification of the different procedures performed on patients that include surgeries and diagnostic exams, as noted by the American Speech-Language Hearing Association.
For example, the three-digit numerical sequences for diseases of the respiratory system are from 460 to 519 and 290 through 319 are for mental disorders. For a specific disease there can be different subcategories, such as 250.0 is for diabetes mellitus and no complications and 250.4 stands for diabetes mellitus with associated renal problems, as noted by the Medical Billing & Coding Certification website.