Overview - ISO/TS 21526:2019 (MetaRep)
ISO/TS 21526:2019, "Health informatics - Metadata repository requirements (MetaRep)," defines requirements for collections of metadata about data elements, models and datasets in healthcare environments. The Technical Specification focuses on metadata that describes persisted healthcare data (not message specifications) and prescribes governance, administration and content models to support consistent metadata registries or dictionaries. It provides healthcare-specific refinements and sensible restrictions to promote adoption while preserving interoperability between metadata registries and enabling tooling for code generation and metadata-driven applications.
Key topics and technical requirements
- Metadata framework and governance: Specifies a framework for managing registry content, administration, registration authorities and registration status to ensure controlled evolution of metadata.
- Basic data types: Defines common primitive/value types used in healthcare metadata (e.g., BLOB, Boolean, Date, Datetime, Integer, Phone_Number, Postal_Address, String) for consistent value domains.
- Common facilities: Covers reusable constructs such as Concept, Concept_System, Classification, Namespace, Scoped_Identifier, Semantic_Relation, Contact, Reference_Document and Naming_Convention to support metadata organization and discovery.
- Data element description: Defines Data_Element, Data_Element_Concept, Conceptual_Domain, Value_Domain, Permissible_Value, Datatype, Unit_of_Measure and Derivation_Rule - enabling explicit, machine-readable definitions of clinical and administrative data items.
- Data model description: Includes Information_Model, Entity_Type, Attribute, Relationship, Diagram and Constraints to represent structure and relationships of persisted datasets.
- XML schema and mapping: Addresses XML_Schema features and MDR_Mapping to support export/import and mapping between registries and systems.
- Healthcare-specific refinements: Extends ISO/IEC 11179 and other ISO/IEC JTC 1/SC 32 metadata standards to handle the broader variety of healthcare value domain types and governance needs while suggesting simplifications to encourage wider adoption.
Practical applications and who uses it
ISO/TS 21526:2019 is used to:
- Build and operate metadata repositories (MDRs) and clinical data dictionaries for EHRs, registries and research datasets.
- Ensure semantic interoperability across hospitals, health information exchanges, public health reporting and clinical research by standardizing data element definitions and value domains.
- Support data governance and stewardship workflows (registration, versioning, authority, classification).
- Drive tooling and automation: enable code generation, validation rules, import/export mappings and configuration of clinical applications from metadata.
Primary users include health informaticians, metadata managers, EHR vendors, data architects, implementers, standards bodies, clinical researchers and health IT product teams.
Related standards
- ISO/IEC 11179 series - metadata registries (MDR) (refined by ISO/TS 21526 for healthcare)
- ISO/IEC JTC 1/SC 32 standards on metadata and data elements
Keywords: ISO/TS 21526:2019, MetaRep, metadata repository, health informatics, metadata registry, ISO/IEC 11179, data element, value domain, semantic interoperability, EHR, data governance.
