International Statistical Classification of Diseases and Related Health Problems (ICD)

ICD serves a broad range of uses globally and provides critical knowledge on the extent, causes and consequences of human disease and death worldwide via data that is reported and coded with the ICD. Clinical terms coded with ICD are the main basis for health recording and statistics on disease in primary, secondary and tertiary care, as well as on cause of death certificates. These data and statistics support payment systems, service planning, administration of quality and safety, and health services research. Diagnostic guidance linked to categories of ICD also standardizes data collection and enables large scale research.

For more than a century, the International Classification of Diseases (ICD) has been the basis for comparable statistics on causes of mortality and morbidity between places and over time. Originating in the 19th century, the latest version of the ICD, ICD-11, was adopted by the 72nd World Health Assembly in 2019 and came into effect on 1st January 2022.   

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ICD purpose and uses

As a classification and terminology ICD-11: 

  • allows the systematic recording, analysis, interpretation and comparison of mortality and morbidity data collected in different countries or regions and at different times;
  • ensures semantic interoperability and reusability of recorded data for the different use cases beyond mere health statistics, including decision support, resource allocation, reimbursement, guidelines and more.

ICD-11 Highlights

  • Legally mandated health data standard (WHO Constitution and Nomenclature Regulations).
  • In effect from January 2022.
  • Conceptual framework independent of language and culture.
  • Integration of terminology and classification.
  • End-to-end digital solution (API, tools, online and offline).
  • Up-to-date scientific knowledge.
  • Comparable statistics and semantic interoperability - for 150 years.
  • ICD-11 is accessible to everybody.
  • ICD-11 is distributed under Creative Commons Attribution-NoDerivs 3.0 IGO license.
  • ICD-11 enables, for the first time, the counting of traditional medicine services and encounters.
  • The 11th revision is more extensive and has greater implications for what can be done with the ICD, and how, than any revision since the 6th, in 1948.


ICD-11 use cases

Uses of the ICD are diverse and widespread and much of what is known about the extent, causes and consequences of human disease worldwide relies on use of data classified according to ICD. See below just a few examples:

Certification and reporting of Causes of Death 

Information on what people die of is recorded on standard forms, analyzed and reported following ICD standards. The information reliably provides a long-term trend of the health of a population. It also can serve short-term monitoring of epidemiological information, like in an epidemic or pandemic.
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Morbidity coding and reporting including Primary care

Accurate and precise information on what people fall sick from and are treated for is recorded and reported with ICD. This includes all levels of health from primary to secondary and tertiary care. This information further serves policy design, planning and monitoring of all aspects of the health of a population.
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Casemix and Diagnosis-Related Grouping (DRG)

ICD-coded information is used for resource allocation or lumpsum payments of statistically equal groups.
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Assessing and monitoring the safety, efficacy, and quality of care

Quality of care uses ICD-coded information to describe the situation of the patient, outcome of treatment and incidents or near-incidents including mechanisms and involved objects such as the failure of an infusion pump or the accidental wrong dosage of a medicament by the patient in line with the WHO recommendations for patient safety incident reporting and learning systems (page 12).
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Cancer registries 

Cancer registration provides detailed information over time on cancer patients. Information on the type of cancer, its location, spread and behavior is coded with ICD.
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Antimicrobial resistance (AMR)

Antimicrobial resistance (AMR) represents a major threat to human health with significant global economic and security implications. ICD provides the details recommended by the Global Antimicrobial Resistance and Use Surveillance System (GLASS). This enables the recording and reporting of the infection, the specific agent, and the level and type of resistance to specific drugs.
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Researching and performing clinical trials and epidemiological studies

Comparability of coded information in multiple languages and with common diagnostic approaches allows the pooling of information from different sites, both globally and locally, for research and trials. ICD provides all levels of detail required for complete clinical and research documentation across languages, borders and settings.
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Assessing functioning 

The ability to carry out tasks by oneself and participate in daily life are means by which to describe, in summary, the overall functioning of a person. It can also be used to track the situation in general or before and after treatment. ICD includes a set of functioning categories based on the WHO disability assessment scheme (WHODAS2) that allow users to calculate a functioning score.
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Coding traditional medicine conditions

Traditional medicine is an enduring and important area of health care in many countries. To better reflect this reality, ICD-11 includes a supplementary chapter for optional dual coding use, entitled ‘Traditional medicine conditions’. ICD-11 enables, for the first time, the counting of traditional medicine services and encounters; the measurement of their form, frequency, effectiveness, safety, quality, outcomes, and cost; comparison with mainstream medicine; and research, due to standardized terms and definitions nationally and internationally. This supplementary chapter is a subclassification for optional use. This chapter is not intended for mortality reporting. Coding should always include also a category from the chapters 1-24 of ICD.
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Interoperability standards in WHO Digital Guidelines and for Digital Documentation of COVID-19 Certificates (DDCC)

ICD-11 has combined the updated classification structure with what was formerly the index of ICD. Furthermore, it has systematically redesigned the additional information included in ICD-10 and several of its derivatives in addition to other WHO nomenclatures and terminologies. As a result, ICD-11 has a broad terminological basis that allows users to code clinical terms in records as well as in other documents, such as COVID-19 vaccine certificates. Due to its multilingual design and the controlled translation environment, it is a reliable tool for communication across settings, borders and languages.
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ICD-11 webinars

News

ICD Implementation across WHO Member States

Learn more about ICD-11

9 February 2022

ICD-11 Fact Sheet

The global standard for health data, clinical documentation and statistical aggregation.Multiple uses, including primary careThoroughly and scientifically...

Eleventh Revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11) Digital Version Terms of Use and License...

The latest version of the ICD, ICD-11, was adopted by the 72nd World Health Assembly in 2019 and came into effect on 1st January 2022. ...

Emergency use ICD codes for COVID-19 disease outbreak

Since the beginning of the pandemic and in response to member state requests, the classification and terminologies unit has been progressively activating emergency codes for COVID-19 in ICD-10 and ICD-11 after consultation with the relevant committees and reference groups of the WHO Family of International Classifications (WHO-FIC) Network.

ICD-10

All Member States are committed to using the most recent version of ICD. 2022 is the first year where ICD-11 is officially in effect. 

Previous online versions of ICD-10:

ICD History

First World Health Assembly 

Convention of 30 April 1948 

The Delegates entrusted WHO, as one of its functions, with the task of establishing and revising the necessary international nomenclatures of diseases and causes of death, giving the World Health Assembly authority to adapt regulations in respect, such as nomenclatures, for consideration and action, the International Statistical Classification of Diseases, Injuries and Causes of Death and accompanying recommendations, destined to improve international uniformity and comparability of statistics of morbidity and mortality.

ICD revisions under the auspices of WHO

ICD RevisionICD Coming into effectICD Adoption
6th Revision     
into effect 1948 adopted 1948 (WHA1.36)
7th Revision into effect 1 Jan 1958  adopted May 1956 (WHА9. 29)
8th Revisioninto effect 1 Jan 1968adopted May 1966 (WHA19.44)
9th Revisioninto effect 1 Jan 1979  adopted May 1976 (WHA29.34)
10th Revision into effect 1 Jan 1993adopted May 1990 (WHA43.24)
11th Revisioninto effect 1 Jan 2022adopted May 2019 (WHA72.15)