ICD–11 is the international standard for the systematic recording, reporting, analysis, interpretation and comparison of mortality and morbidity data. The 11th revision replaces the 10th revision (ICD-10) and is the result of collaboration with clinicians, statisticians, classifications, and IT experts from around the world.

ICD–11 enables countries to count and identify their most pressing health issues by using an up-to-date and clinically relevant classification system. Health conditions and accidents are assigned ICD–11 codes and the resulting data can be used by governments to develop effective public health policies, and measure their impact.

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Our ICD-11 overview gives further information about:

  • Why ICD-11 has been produced
  • The revision process
  • Main structural changes between ICD-10 and ICD-11
  • ICD-11 electronic tools
  • Field trials and how the classification has been tested and trialled. 

ICD-11 Information and tools are available on the WHO ICD-11 Home Page.

ICD-11 Benefits

  • Free to use under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 IGO license
  • Reflects critical advances in science and medicine, aligning the classification with the latest knowledge of disease treatment and prevention.
  • Extensive clinical input, for example, the Mental, Behavioural and Neurodevelopment Disorders chapter (Chapter 06) and associated Clinical Descriptions and Diagnostic Guidelines (CDDG) have been developed with input from almost 15,000 mental health and general practice clinicians from over 150 countries, resulting in a culturally validated update that reflects current clinical research and practice.
  • Fully electronic, providing access to 17,000 diagnostic categories, with over 100,000 medical diagnostic index terms. The powerful index-based search algorithm interprets more than 1.6 million terms.

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  • Digital health ready, for use in multiple IT-environments, with a new API that provides easy access to the ICD-11 Browser and Coding Tool and greatly reduces the development burden for system developers.
  • Easy to use online or offline, using free 'container' software
  • ICD Tabular, Index and Reference Guide are presented together with a suite of web services including the Implementation and Transition Guide, multilingual support, and in-built user guide.
  • The introduction of extension codes allows the flexible addition of detail relevant for clinical documentation, and device or substance safety. Extension codes provide for the recording of medicaments with WHO International Non-proprietary Names (INN2) and WHO Medical Device nomenclature (ATC/DDD), as well as documenting the severity of conditions, anatomy, or histopathology.
  • Content-model based so each code and category have a consistent meaning and allows definitions, signs and symptoms, and other content related to diseases to be defined in a structured way, so they can be recorded more accurately.
  • Aligns with other classifications and terminologies such as ICD-O (International Classification of Disease for Oncology)
  • Foundation layer brings together ICD, International Classification of Functioning, Disability and Health (ICF) and International Classification of Health Interventions (ICHI) in one place
  • Ensures consistency with earlier ICD versions because it has been built using the past revisions of ICD as its basis, so data analysis between revisions will be possible
  • New supplementary section for Functioning Assessment allowing for the monitoring of functional status before and after the intervention, and permits the calculation of a summary functioning score using the WHO Disability Assessment Schedule 2.0 (WHODAS 2.0) or the WHO Model Disability Survey (MDS)
  • Incorporates all rare diseases. In collaboration with several partners, including OrphaNet, ICD11 has incorporated all rare diseases. Only a few of these have an individual code, but all have their own Uniform Resource Identifier (URI), allowing rare disease Registries and researchers access to detailed epidemiological data on conditions of interest;
  • The use of the URI facilitates linkage with other information interchange products and terminologies
  • Overall coding improvements in ICD–11 allow more precise and more detailed data recording and collection. Examples include:
  • Codes for full documentation of patient safety, in line with the WHO patient safety framework
  • Necessary detail for cancer registration is fully embedded in ICD–11
  • Specific coding for clinical stages of HIV
  • More clinically relevant coding for complications of diabetes.
  • Codes for common skin cancers basalioma, and melanoma subtypes. Classification of heart valve diseases and pulmonary hypertension, now matching current diagnostic and treatment capacity.
  • Coding for traffic accidents and causes of injuries is now consistent with current international practice for data documentation and analysis.

ICD-11 Chapter Reviews

NHS Digital hosts the UK WHO-FIC Collaborating Centre and as part of our role we contribute to the evaluation of ICD-11 for morbidity coding. During 2020 and 2021 we offered clinicians and other users of the classification an opportunity to review chapter content and provide feedback to us. The Chapter reviews have now closed.

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ICD-11 Timescales

In May 2019, the World Health Assembly adopted the eleventh revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11), to come into effect on 1 January 2022, subject to transitional arrangements.  The UK is a Member State of the World Health Organization and in our role as a WHO Collaborating Centre, NHS Digital took part in ICD-11 Field Trials during 2017 and 2018. The UK’s status as a WHO Member State requires us to submit mortality and morbidity data for international comparison using ICD.

In acknowledgement of the different levels of complexity facing different countries, the WHO has provided transitional arrangements from 1 January 2022 for at least five years. The UK, like many countries, has a sophisticated national health informatics ecosystem comprising clinical information standards, national information flows and a variety of IT systems. Because of this, the implementation roadmap for ICD-11 for morbidity coding will be complex.

ICD-11 Pre-Implementation Project

Since the second half of 2021 we have worked with our partners in the UK’s devolved administrations to engage with strategic stakeholders as part of our preliminary preparations for the implementation of ICD-11. During 2022 we will continue and extend that engagement as part of a 12 month pre-implementation project that will deliver an ICD-11 implementation roadmap. We will engage with NHS providers, EPR and encoder system vendors and a range of other stakeholders to help us develop a realistic implementation plan. Further details on the objectives and activities of this pre-implementation project will be provided here and via other channels from May 2022.

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When the ICD-11 implementation roadmap is agreed, development will be managed by NHS Digital and we will seek approval to publish a new information standard through the Data Alliance Partnership Board.  This will include implementation requirements and timescales to allow NHS organisations and system suppliers time to implement the requirements of specific collections.  Although we continue to work closely with our partners in the devolved administrations, they will determine their own implementation timeframes in line with their needs and priorities. It is important to state that our focus is exclusively on the implementation of ICD-11 for morbidity. The Office for National Statistics is managing the implementation of ICD-11 for mortality coding and we are working closely with colleagues in the ONS so that we can share work and learn from each other.

In the meantime, ICD-10 remains a mandatory information standard – as detailed in the NHS Data Dictionary.  NHS organisations and system suppliers must continue to follow the current information standard ICD-10.

Further details on ICD-11 from WHO can be found below:

ICD-11 presentation to representatives of the Permanent Missions of Member State at the WHO Head Quarters in Geneva on Monday 14 May 2018 in advance of the WHA and Executive Board meetings.

ICD-11 Electronic Tools

The two electronic tools WHO have developed to access ICD-11 are the Coding Tool and Browser. User guides are available by selecting ‘Help’ on the Coding Tool page and under the ‘Info’ tab on the Browser page.

ICD-11 Queries

ICD-10 is the current standard used within the NHS in England for the collection of diagnostic information for all inpatient episodes and day cases. As the UK WHO-FIC Collaborating Centre we are currently evaluating ICD-11 and developing our knowledge of the classification. If you have any general queries about ICD-11 or queries about the content of ICD-11 you can submit these to us at information.standards@nhs.net.

ICD-11 Content Change Requests

For queries regarding the content of ICD-11 where you have identified an error, discrepancy, missing content or missing or incorrect search terms in the Coding Tool please submit information about the change that you believe is required using the ICD-11 Content Request Template and email it to us at information.standards@nhs.net. We will review this information prior to making a submission to the platform on your behalf (where appropriate).