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Product Brief - Data Types: Abstract Specification

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Product Name - Data Types - Abstract Specification

Standard Category

  • Health Information Exchange Standards

Integration Paradigm

  • Foundation


Normative, ANSI Standard


ANSI/HL7 V3 DT, R1-2004; currently balloting HL7 V3 DT R2 - HL7 Version 3 Standard: Data Types - Abstract Specification, Release 2
Normative Ballot 4 - September 2009


Every attribute in the Reference Information Model (RIM) is has a data type. This specification defines the semantics of these data types.


The specification defines the semantics of the datatypes - that is, what they mean, how they behave, and the operations that can be performed on the data types. The data types are defined by a combination of UML diagrams, value tables, formal language statements, and extensive narrative that explains their meaning. The data types can be found throughout HL7 standards where ever the RIM is used. Additionally they may used in other contexts as well.

The specification is abstract - it is a statement of meaning - and the data types cannot be implemented directly based on the definitions found in this specification. Implementations are provided in the XML implementations or in the ISO standard "Healthcare Data types" (ISO 21090) (still being finalised)

Business Case (Intended Use, Customers)

The primary intent of this document is internal to HL7 - to provide an enduring statement of the meaning of the data types that has no dependence on external factors that may change. For implementers of Hl7 standards, the document contains secondary supplemental information that further clarifies the use of the data type beyond that found in the implementations referred to above.


OMG's Model Driven Architecture (MDA) defines the concept of a Platform Independent Model (PIM), which has the advantage of being able to be implemented across multiple technologies without loss of meaning, thereby protecting the investment of the designer as technologies change. The abstract data types extend this notion in that they are independent of any other language or standard, and therefore their meaning is not changed as other languages, platforms and technologies gradually advance over time. In addition, by defining it's own framework for defining standards, the specification is able to make formal statements of meaning about things that would not otherwise be possible. This means that the fundamental HL7 definitions of the meaning of the data can be preserved and implemented in a variety of language and specification frameworks over time, such as UML, XML, ASN.1, where each include their own data types.

The cost of these things is that it is not possible to implement the standard directly; for this reason HL7 additionally publishes implementation specifications for end-implementers to actually use.

Implementations/ Case Studies (Actual Users)

The data types are used everywhere any v3 specification is used.


Work Groups

Modeling and Methodology



Relationship to/ Dependencies on, other standards

Links to current projects in development