Short answer: ICD is the WHO's International Classification of Diseases, used to code diagnoses and causes of death for statistics and, in many countries, for billing. ICD-10 has been in use since the 1990s; ICD-11, adopted by the World Health Assembly in 2019, came into effect on 1 January 2022. Countries move to ICD-11 at their own pace, so most records today still contain ICD-10 codes.
What changed
- Code format: ICD-10 codes start with a letter and two digits (I10, essential hypertension; E11, type 2 diabetes). ICD-11 codes start with a digit or letter pattern such as BA00 (essential hypertension) or 5A11 (type 2 diabetes).
- Structure: ICD-11 has a foundation of entities linked in several ways, from which the statistical classification is derived, and allows codes to be combined (post-coordination) to add detail such as severity or body site.
- Digital design: ICD-11 is built to be used through software, with an online browser and an API, and in multiple languages.
- Content: new chapters (for example traditional medicine, conditions related to sexual health) and updated knowledge.
Why ICD-10 is still everywhere
Payment systems, national registries and software were built around ICD-10, and changing them takes years. Several countries use national modifications, such as ICD-10-CM in the United States or ICD-10-GM in Germany, which add detail. During the transition records may carry both, and mappings between ICD-10 and ICD-11 are published by the WHO.
In Anpheros
In Anpheros, conditions are stored with ICD-10 codes, which most systems read today; Anpheros Search links symptoms and conditions to their ICD-11 entries at the WHO. Developers: FHIR code systems and the symptom data API.
Related pages
- What is SNOMED CT? Clinical terms as codes, explained simply
- What is a LOINC code? The number behind each test on your lab report
- ICD-10 vs ICD-10-CM vs ICD-10-GM
- SNOMED CT vs ICD-10
Sources
Frequently asked questions
Has ICD-11 replaced ICD-10?
As the WHO standard, yes, since January 2022. In practice most countries still use ICD-10 or a national version while they transition.
What is the ICD-11 code for essential hypertension?
BA00; in ICD-10 it is I10.
What is ICD-10-CM?
The US clinical modification of ICD-10, with more detailed codes, used for diagnoses in the United States.
Do I need to know my ICD codes?
Not usually, but they appear on discharge letters and sick notes, and a record that keeps them is easier for other systems to read.
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