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Background |  Areas of Current Investigation


The International Classification of Diseases (ICD) is an international standard for classifying diseases and other health problems (clinical diagnoses). It is used for all general epidemiological and many health management purposes. These uses include the analysis of the general health situation of population groups and monitoring of the incidence and prevalence of diseases and other health problems in relation to other variables, such as the characteristics and circumstances of the individuals affected. The World Health Organization (WHO) is responsible for the continued maintenance and development of the ICD standard. [Adapted from the WHO's ICD Homepage].

Areas of Current Investigation

The current version of ICD is 10 (ICD-10), which was completed in 1992.

A related standard is the ICD-CM (Clinical Modification), published by the U.S. National Center for Health Statistics. It provides for additional morbidity detail. The latest version (2001) of ICD-CM is ICD-9-CM, which is the official system of assigning codes to diagnoses and procedures associated with hospital utilization in the United States.

On August 22, 2008, the Centers for Medicare & Medicaid Services (CMS) issued a notice in the Federal Register (PDF, 837 KB ) that would replace the ICD-9-CM code sets with greatly expanded ICD-10 code sets, effective October 1, 2011.

A draft of ICD-10-CM has been produced; however, the ICD-10-CM codes are not currently valid for any purpose or use. The effective implementation date is October 1, 2013.

ICD-10-CM will include the addition of the following:

  • Information relevant to ambulatory and managed care encounters.
  • Expanded injury codes.
  • Combination diagnosis/symptom codes to reduce the number of codes needed to fully describe a condition.
  • Sixth and seventh characters.
  • Common fourth and fifth digit subclassifications, laterality, and greater specificity in code assignment. 

The new structure will allow for expansion beyond what was possible with ICD-9-CM.  Major health initiatives that should significantly improve with the implementation of ICD-10-CM include the following:

  • Quality measurement.
  • Pay-for-performance.
  • Medical error reduction.
  • Public health reporting.
  • Biosurveillance.
  • Actuarial premium setting.
  • Cost analysis
  • Service reimbursement. 

Another related standard is ICD-O-3 (Oncology), published by the Surveillance Epidemiology and End Results (SEER) Program of the National Cancer Institute (NCI). The ICD-O-3 standard is used to capture cancer diagnosis and treatment information. The standard is used by the North American Association of Central Cancer Registries, Inc. (NAACCR, Inc.) and by local and State cancer registries across the United States for disease management and research.

The information on this page is archived and provided for reference purposes only.