The family of international health-related classifications of the WHO includes three groups of classifications:
- Reference classifications
- ICD - International Classification of Diseases
- ICF - International Classification of Functioning, Disability and Health
- ICHI -International Classification of Health Intervention (under development)
- Derived classifications such as e.g. ICD-O-3, derived from one of the reference classifications
- Related classifications , i.e. classifications such as ATC/DDD, with close links to the reference classifications and often used in conjunction with them in practice, but not developed by the WHO.