ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification)

The International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) is the official system used in the United States to classify and assign codes to health conditions and related information. The use of standardized codes improves consistency among physicians in recording patient symptoms and diagnoses. 

The ICD-9-CM contains a list of alphanumeric codes which correspond to diagnoses and procedures recorded in conjunction with hospital care in the United States. For example, a patient with acute appendicitis will be assigned a code of 540. This code may be entered onto a patient’s electronic medical record (EMR) and used for diagnostic, billing and reporting purposes. Related information also classified and codified in the system includes symptoms, patient complaints, causes of injury, and mental disorders. 

The United States Department of Health & Human Services and the Centers for Medicare and Medicaid Services created ICD-9-CM as an extension of the Ninth Revision, International Classification of Diseases (ICD-9), which the World Health Organization (WHO) established to track mortality statistics across the world.

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Educating physicians will help ease the transition from ICD-9 to ICD-10 coding.

Preparation for ICD-10 varies widely among health care providers.

This was last updated in April 2010
Posted by: Margaret Rouse

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