The WHO Family of International Classifications
The WHO constitution mandates the production of international classifications on health so that there is a consensual, meaningful and useful framework which governments, providers and consumers can use as a common language.
Internationally endorsed classifications facilitate the storage, retrieval, analysis, and interpretation of data. They also permit the comparison of data within populations over time and between populations at the same point in time as well as the compilation of nationally and internationally consistent data.
The purpose of the WHO Family of International Classifications (WHO-FIC) is to provide an appropriate selection of classifications for a range of settings in the health field around the world.
The basis for the WHO-FIC and the principles governing the admission of classifications are set out in the paper on the "WHO Family of International Classifications: definition, scope and purpose". This paper also provides a protocol for those wishing to submit a classification for inclusion in the WHO-FIC.
Classifications and Clinical Terminologies
Classifications capture snapshot views of population health using such parameters as death, disease, functioning, disability, health and health interventions, which inform management and decision making process in the health system. Over time, they also provide insight on trends which informs the planning and decision making processes undertaken by health authorities. The multiplicity of potential perspectives on health mandates a variety of classifications. Their necessary evolution poses challenges for consistency. More recently, the varied applications in health information systems and the general availability of information and telecommunication technologies (ICT) has highlighted the need for increased interoperability.
The base line information that is aggregated for public health purposes is increasingly derived from health records which contain patient care related information as well as information that is crucial for management, health financing and general health system administration. Accuracy and consistency of the health records is crucial to ensure the quality of care and sound management of health systems resources. This calls for precise and consistent use of clinical terminologies and recognition of the particular importance of semantic interoperability.
Possible synergies between classifications and clinical terminologies have been identified as crucial for future work, particularly from the perspective of a growing automation of information processing. WHO and its network of Collaborating Centres are taking steps in that direction.
Types of Classifications
The WHO-FIC is comprised of the following three types of classifications:
1. Reference Classifications:
Reference classifications are the main classifications covering the essential and basic parameters of health. These classifications have been prepared by the World Health Organization and approved by the Organization's governing bodies for international use.
- International Classification of Diseases (ICD)
- International Classification of Functioning, Disability and Health (ICF)
- International Classification of Health Interventions (ICHI)
2. Derived classifications:
Derived classifications are based on the reference classifications (i.e. ICD and ICF). Derived classifications may be prepared either by building on the reference classification structure and categories to provide additional detail beyond that provided by the reference classification, or they may be prepared through rearrangement or aggregation of items from one or more reference classifications. Derived classifications in the WHO-FIC include:
- International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3)
The ICD-10 for Mental and Behavioural Disorders Clinical Descriptions and Diagnostic Guidelines
The ICD-10 for Mental and Behavioural Disorders Diagnostic Criteria for Research
- Application of the International Classification of Diseases to Neurology (ICD-10-NA)
- Application of the International Classification of Diseases to Dentistry and Stomatology, 3rd Edition (ICD-DA)
3. Related classifications:
Related classifications are those that connect to or overlap with reference classifications, or are otherwise associated with the reference classification at specific levels of structure only. Related classifications in the WHO-FIC include:
- International Classification of Primary Care, Second edition (ICPC-2)
- International Classification of External Causes of Injury (ICECI)
- Technical aids for persons with disabilities - Classification and terminology (ISO9999)
- The Anatomical Therapeutic Chemical Classification System with Defined Daily Doses (ATC/DDD)
- International Classification for Nursing Practice (ICNP)