More Comprehensive Scope

ICD-10, which is developed, maintained and published by the World Health Organization, has been available for implementation since 1993. It represents the broadest scope of any previous ICD revision to date. ICD-10 is more comprehensive than current standards and extends well beyond the traditional causes of death and hospital admission. The expansion of content and specificity to conditions and situations that are not diseases are particularly relevant for use of the classification system outside the hospital setting.

The table below gives examples of some of the subcategories provided in ICD-10 for the capture of risk factors to health, such as lifestyle, life management, psychosocial circumstances, and the occupational or physical environment. Such an expanded scope may attract new users to ICD-10 and may increase the number of databases in which the codes appear. This is important given the evolution of integrated health information systems.

Examples of subcategories provided ICD-10 for capture of risk factors to health


ICD-10 Code

Code Title


Stressful work schedule


Occupational exposure to dust


Occupational exposure to vibration


Exposure to air pollution


Exposure to water pollution


Inadequate housing


Problems in relationship with spouse or partner


Tobacco use


Lack of physical exercise


Inappropriate diet and eating habits




Lack of relaxation and leisure

Improved Specificity and Currency

The results of a mapping from ICD-9-CM to ICD-10 carried out in Australia showed that, of a total of 13,600 ICD-10 codes, 50.8% were more specific than the ICD-9-CM codes, 31.5% were as specific, and only 11.5% either were less specific or could not be compared. (Options research paper on future long term suitability of using ICD-9-CM in Australian hospitals. Canberra: National Coding Centre; 1994. p. 14.) Although the study did not address ICD-9, the gains in specificity from ICD-9 to ICD-10 should be even more significant because ICD-9 is less specific than ICD-9-CM (ICD-9-CM, a US modification of ICD-9, contains additional detail and specificity not found in ICD-9). This increased specificity contributes to more relevant data for epidemiological research and decision-support purposes. Gains in the level of specificity also increase the sensitivity of the classification when making refinements in applications, such as grouping methods.

Because the current standards were developed for implementation in the late 1970s, their terminology and content continue to become less and less current. ICD-10 introduces both new terminology and new clinical concepts, giving it a higher level of clinical credibility and acceptance.

Ongoing Maintenance and Updating

Adaptability, maintenance and updating are critical if a classification system is to be dynamic enough to be used in our rapidly changing world. Unlike previous revisions, ICD-10 allows for enhancements to accommodate newly discovered diseases, such as AIDS. WHO has established an ongoing maintenance and updating process that ensures input from member states, such as Canada, as well as from interested professional bodies. In addition, there are plans to share updates internationally by means of the latest technology. This enhances the long-term viability of the classification system.

Canadian Version of ICD-10

CIHI has permission from WHO to reproduce, distribute and enhance the ICD-10 classification system. This ensures that the classification can evolve and continue to stay relevant to Canada's health systems. The Canadian enhancement of ICD-10, known as ICD-10-CA, has added approximately 3,000 more codes for morbidity data collection purposes in Canada.

Single Set of National Standards

Historically, a variety of medical classification standards were used in Canada. Previously, 2 standards were used at the national level for diagnosis classification: ICD-9 and ICD-9-CM. There were also 2 standards for procedure classification: CCP and the procedure section of ICD-9-CM. Although there were inherent similarities between the 2 diagnostic classifications and between the 2 procedure classifications, there were also some differences. The differences continually increased as updates to the ICD-9-CM were introduced by the U.S. annually. Differences also existed between various publications of ICD-9-CM. This mixture of standards across jurisdictions presented some obstacles in compiling national databases and conducting interprovincial comparisons. A single set of national standards has eliminated these obstacles and reduced the inefficient resources spent on supporting 2 sets of standards.

International Comparability

As a member state of WHO, Canada is governed by its nomenclature regulations, which make ICD-10 the international standard for reporting of illness and death. Implementation of ICD-10 began in a few countries in 1994. Canada's implementation of ICD-10 ensures internationally comparable data.

More Effective Structure, Presentation and Guidelines

Structural changes introduced in ICD-10 contribute to its effectiveness. Significant enhancements to the system's structure and presentation include an enlarged coding frame (i.e., more than double the number of available codes through the use of alphanumeric characters), hierarchic and logical presentation of codes, increased use of combination codes and improved format of the classification. ICD-10 includes an additional volume of interpretation guidelines for both illness and death. This makes the application of the codes easier and enhances training.