| Medical terminologies: ICD
The International Statistical Classification of Diseases and Related Health Problems
International classification system for causes of death.
"The purpose of the ICD ... is to promote international
comparability in the collection, classification, processing, and presentation of mortality statistics".
Designed to support "the collection, classification, processing, and presentation of mortality statistics".
Used to summarise the incidence of
diseases and operations on national and worldwide levels.
The United Nations World Health Organization (WHO), Geneva, in collaboration with 10 international centres.
||In Europe, as the
Bertillon Classification or International List of Causes of Death, in 1893.
ICD-1 was introduced in the USA in 1900.
New revisions have been released generally every ten years since then.
ICD-10 The International Statistical Classification of Diseases and Related Health Problems, tenth revision,
second edition, 2005 (available in electronic format).
Modifications of ICD-10 include:
ICD-10 CM International Classification of Diseases, 10th Revision, Clinical Modification
ICD-10 PCS International Classification of Diseases 10th revision, Procedure Classification System.
ICD-9 was released in 1979. The first edition of ICD-10 was released in 1994
|background / derivation
The history of the ICD extends back to the
late 19th century, when the need for
standardizing classification concepts and
terminology was recognized by the medical
community in Europe.
ICD is divided into categories based on a five digit code (which limits the size of the vocabulary), where round numbers represent the more general concepts.
ICD-10 has some 8,000 cat-
egories (ICD-9 had only 4,000) and 12,500 codes.
ICD in form is a strict hierarchy; code determines position in hierarchy.
Deaths are ranked on a list of 113 causes (except
infant deaths, which are ranked separately on a list of 130
A selected list of 39 causes
of death is used to show mortality data for
"In practice, the ICD has become the international standard diagnostic classification for all general epidemiological and many health management purposes."
||ICD codes are used world-wide for morbidity and mortality statistics.
They have been the most widely used codes in healthcare.
"ICD-10 is used within the acute sector of the NHS and the classification codes are mandatory for use across England" [NHS].
"Electronic and bound versions
can be purchased from WHO
however, NCHS and the States
are using a copy modified and
corrected by NCHS. The NCHS
version converts the English
spellings to American spellings
and incorporates changes
made after the WHO version
was published. A WHO
copyright precludes NCHS from
electronically distributing the
ICD-10 version being used in
the United States."
In the UK, "NHS bodies are not required to apply for a licence and are permitted to reproduce ICD-10 codes for administrative purposes within the NHS only" (NHS}.
("NHS Connecting for Health holds the licence for the UK to use the ICD-10 codes within the NHS as the joint UK World Health Organisation Collaborating Centre for the Classification of Diseases" [NHS]).
The ICD family of classifications.
Methods Inf Med 1995 Mar;34(1-2):172-5.
The history from the Sixth to the Ninth Revisions of the ICD is described. The 10th revision is presented as the 21st Century classification. The preparation of the ICD-10 included a long process with two expert committee meetings. A classification of diseases can be defined as a system of categories to which morbid entities are assigned according to established criteria. The purpose of the ICD is to permit the systematic analysis, interpretation and comparison of mortality and morbidity data collected in different countries or areas and at different times. In practice, the ICD has become the international standard diagnostic classification for all general epidemiological and many health management purposes. It was felt that the main ICD (the three- and four-character classification), covered by three volumes of ICD-10, could not incorporate all this additional information and remain accessible, and relevant to its traditional users, so the idea arose of a "family" of disease and health-related classifications, including volumes published separately form the main ICD, to be used as required. A statistical classification of diseases must be confined to a limited number of mutually exclusive categories, able to encompass the whole range of morbid condition, and must have well defined place in the list of categories. Consequently, throughout the classification, there will be residual categories for other and miscellaneous conditions that cannot be allocated to the more specific categories. As few conditions as possible should be classified to residual categories. Consequently, throughout the classification, there will be residual categories for other and miscellaneous conditions that cannot be allocated to the more specific categories...
International Statistical Classification of Diseases, 10th Revision, Second Edition.
World Health Organization, 2005.
The classification of diseases and related health problems in 22 chapters:
Volume 2: Instruction Manual
- Certain infectious and parasitic diseases
- Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Endocrine, nutritional and metabolic diseases
- Mental and behavioural disorders
- Diseases of the nervous system
- Diseases of the eye and adnexa
- Diseases of the ear and mastoid process
- Diseases of the circulatory system
- Diseases of the respiratory system
- Diseases of the digestive system
- Diseases of the skin and subcutaneous tissue
- Diseases of the musculoskeletal system and connective tissue
- Diseases of the genitourinary system
- Pregnancy, childbirth and the puerperium
- Certain conditions originating in the perinatal period
- Congenital malformations, deformations and chromosomal abnormalities
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
- Injury, poisoning and certain other consequences of external causes
- External causes of morbidity and mortality
- Factors influencing health status and contact with health services
- Codes for special purposes
Volume 3: Alphabetical Index
Colorado Department of Public Health and Environment. New International Classification of Diseases (ICD-10): the history and impact. Brief. Mar 2001; no.41.
[Colorado Department of Public Health and Environment]
The International Classification of Diseases (ICD) is a system developed collaboratively between
the World Health Organization (WHO) and 10 international centers so that the medical terms reported
by physicians, medical examiners, and coroners on death certificates can be grouped together for
statistical purposes. The purpose of the ICD and of WHO sponsorship is to promote international
comparability in the collection, classification, processing, and presentation of mortality statistics.
Revisions of the ICD are implemented periodically so that the classification reflects advances in
medical science. Since 1900, the ICD has been modified about once every 10 years, except for the
20-year interval between the last two revisions, ICD-9 and ICD-10. Effective with deaths occurring
in 1999, the United States replaced ICD-9, in use for deaths from 1979 to 1998, with ICD-10.
Publications showing mortality data coded under ICD-10 will differ substantially from those under
ICD-9 because of changes in coding rules, changes in category names and ICD numbers, and changes
in the tabulation lists used to group mortality data. This report will briefly review the history of
ICD, highlight major changes in ICD-10, and discuss the statistical impact the revision will have on
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Entry on OpenClinical: 15 July 2005
Last main update: 29 July 2005