By June Bronnert, MHI, RHIA, CCS, CCS-P

You may be asking: ICD-11. Why now? My answer: Why not now?

The pandemic has shown the power of integrated data capture and collaboration across terminologies and code sets allowing for sharing of information and innovation. ICD-11 leverages the strengths of different systems to create a modernized classification system. ICD-11 will be a major step forward in improving the quality of data and the flexibility of the code set to reflect current and future medical practice. As professionals working with the code sets, this is exciting!

The International Classification of Diseases (ICD) system was intended for review approximately every ten years. As World Health Organization (WHO) released ICD-10 in 1992, it was time for a review and the work for ICD-11 began in 2007. Following the standard revision process, WHO established work groups to begin the revision. The goals of the revision were to:

  • Ensure ICD continues to serve as an international standard
  • Align with scientific and electronic advancements
  • Link to other classification and terminologies

The revision process was comprehensive with widespread input across the international community and scientific organizations. There were field trials and an ICD-11 Revision Conference in 2016. The system underwent several rounds of refinements with a stable version presented at the World Health Assembly. In 2019, the World Health Assembly approved the version for member country use. See 2021 whitepaper “IFHIMA Fosters Planning for ICD-11 Adoption with Global Case Studies” for a detailed discussion of adoption and implementation strategies (sign up required).

ICD-11 Structure
ICD-11 builds upon the structure of prior ICD editions but incorporates new content features reflective of digital and scientific advancements. There are two major features of ICD-11 for users to be aware of:

  • Foundation Component – ICD-11 introduces a foundation component to its structure. The foundation allows for creation of defined tabular lists. ICD-11 for Mortality and Morbidity Statistics (ICD-11 MMS) is the tabular list created for reporting morbidity and mortality codes. The tabular list follows the same category and subcategory structure of prior ICD versions leading to an ICD-11 code.
  • Stem and Extension Codes – Stem and extension codes are new features for ICD-11.
    • Stem codes contain enough meaningful information in the code descriptor to be used independently. Examples of stem codes are:
      • BA00.Z Essential hypertension, unspecified
      • 5C76 Hyperkalaemia
    • Extension codes are designed to add meaning to a stem code in a standardized manner. Examples of extension codes are:
      • XT9T Ageing-related
      • XH70J2 Adenoid basal carcinoma

While stem codes may be reported alone, they may also be reported in conjunction with an extension code or even other stem codes. This linking of codes is known as post-coordination and allows for the codes to fully describe documented conditions.

Structure of an ICD-11 code
ICD-11 codes are alphanumeric. To distinguish ICD-11 codes from ICD-10 codes, the second character of an ICD-11 code is an alphabetical character. The first character represents the chapter value which could be either an alpha or numeric character. The letters “O” and “I” are omitted to avoid confusion with numeric values “0” and “1”.

Here are examples of an ICD-11 codes with stem and extension codes:

  • 2C25.Z Malignant neoplasms of bronchus or lung, unspecified
    • Stem code
    • The first character “2” presents the second chapter (Neoplasms)
  • XA2UD3 Left lung
    • Extension code
    • The first character “X” represents the extension code chapter

Morbidity and mortality are the two high level categories for reporting ICD data.

  • Mortality – Mortality coding focuses on the reporting the cause of death. WHO has established standard rules and guidelines for member countries when reporting the cause of death. For more information on current guidelines please see WHO’s website.
  • Morbidity – Morbidity coding focuses on capturing codes related to an individual state of health. Member countries have established rules and guidelines within their countries based upon their own unique data requirements. In defining how to capture their country’s data needs, some member countries have created their own modification of WHO’s ICD system, such as ICD-10-CM (the Clinical Modification used in the U.S.), ICD-10-CA (used in Canada), and ICD-10-AM (the Australia Modification). While all modifications are based on WHO’s ICD, there are differences in individual codes within each system.

Implementation of ICD-11 varies based upon the category of coding. As the mortality coding is more standardized internationally, WHO recommends international reporting starting January 2022.

Implementation of ICD-11 for morbidity coding is more complex due to individual country data reporting requirements. The implementation process is unique to each member country. Please see IFHIMA white paper for more information regarding recommendations for morbidity implementation preparations in addition to various countries’ plans.

For more information on ICD-11 see:


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About the Author
June Bronnert, MHI, RHIA, CCS, CCS-P
June is Senior Director, Informatics Global Clinical Services, for IMO, Intelligent Medical Objects, and provides HIT subject matter expertise for IMO’s terminology solutions. Prior to IMO, June was the Professional Practice Director at AHIMA, where she was responsible for content development and technical reviews of the Association’s products and resources. June obtained her master’s in health informatics from Northeastern University and her Health Information Management degree from Indiana University. [email protected]