ISO 21090:2011

Overview

ISO 21090:2011 - "Health informatics - Harmonized data types for information interchange" defines a harmonized set of healthcare-focused datatypes to support reliable information exchange between health information systems. The standard declares datatype semantics using ISO/IEC 11404 terminology, provides UML 2.0 class definitions and specifies an XML representation for the datatypes. ISO 21090 is intended primarily for defining external interfaces and messages (interoperability), while also being useful for internal system design.

Key topics and technical requirements

• Datatype collection and categories: covers basic datatypes and healthcare-specific categories such as text & binary, coded datatypes (terminology), identification & location, name & address, quantity, collections, continuous sets, uncertainty and structured text.
• Semantics and value spaces: semantics are declared with ISO/IEC 11404 concepts; conforming systems must align value spaces with those in ISO 21090 where direct conformance is claimed.
• Conformance models: defines direct and indirect conformance mechanisms, requiring implementers to specify which datatypes are supported, how value spaces are constrained, and what operations are provided.
• UML and XML bindings: provides UML 2.0 models for each datatype and a normative XML schema/representation for message-level exchange. Annexes include UML support types, XML schema, and mappings.
• Interoperability orientation: content reflects requirements from HL7 V3, ISO/IEC 11404, CEN/TS 14796 and ISO 13606, emphasizing compatibility with established healthcare messaging and terminology systems.
• Normative references: includes ISO/IEC 8601 (date/time), ISO/IEC 4217 (currency), HL7 V3 Data Types Abstract Specification and others that influence datatype behavior and encoding.

Applications and who uses it

ISO 21090 is used by:

• Health IT architects and system designers defining interoperability interfaces, message formats and APIs.
• EHR/EMR vendors aligning internal models with a shared external datatype vocabulary.
• Standards bodies and integrators creating mappings between HL7, ISO electronic health standards and national profiles.
• Software developers and integrators implementing XML or UML-based exchange formats for clinical data, coding systems and administrative information.

Practical uses include defining data payloads for clinical messages, specifying datatype constraints for APIs, and ensuring consistent representation of coded concepts, quantities and identifiers across systems.

Related standards

• ISO/IEC 11404 (General-Purpose Datatypes) - semantics foundation
• HL7 V3 (Data Types) - primary source of requirements and mappings (Annex D)
• ISO 13606 and CEN/TS 14796 - related healthcare data modelling work
• ISO/IEC 8601, ISO/IEC 4217 - normative references for date/time and currency formats

Keywords: ISO 21090, health informatics, data types, healthcare interoperability, UML, XML, HL7, conformance, healthcare datatypes.