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ISO Datatypes

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This International Standard specifies the shared semantics for a collection of healthcare related datatypes used in a number of health related information standards. This standard declares these datatypes using the terminology, notations and datatypes defined in 11404 rev 2003. In addition to defining the datatypes in these terms, this standard also provides UML definitions of the same datatypes using the terminology, notation and types defined in UML 2.0.

The purpose of this international standard is to provide an agreed common semantic basis for exchanging basic concepts that are commonly encountered in healthcare environments. This standard is based on considerable input from HL7, CEN, and past ISO work on healthcare datatypes.

It is expected that other healthcare information standards and specifications will define mappings for the datatypes specified herein, though direct reference or a mixture of direct reference and mappings may also be expected.

What is a datatype?

There is no clear definition of exactly what is a datatype and where a more complex structure would be appropriate. Generally the definitions of the scope of datatypes revolve around one or more of the following three notions:

  • The relationship between equality and identity
  • Coherency of a single concept

Since of both of these concepts are inherently a matter of perspective, the selection criteria for the datatypes defined in this standard is based on the set that has emerged from the debates held within the various stakeholder standards bodies that define healthcare information standards. Since healthcare information standards and specifications are expected to provide mappings to this standard, the process has been deliberately inclusive. These other standards may choose to represent these datatypes with other more complex structures, but should explain how to interconvert these structures with the datatypes defined herein.

Normative References


Terms and Definitions

Should not include anything in 11404 terms and definitions?

  • HL7
  • CEN





Null and NullFlavor


This section lays out the template that should be generally followed for each type.



Discussion of scope, usage ([+Extension])

Formal definition in 11404 language

Formal definition in UML

Further discussion about why it is defined the way it is.


For each property

 Definition (+parameters if any)
 Discussion of usage