ISO 21090:2011 - provides a set of datatype definitions for representing and exchanging basic concepts that are commonly encountered in healthcare environments in support of information exchange in the healthcare environment; - specifies a collection of healthcare-related datatypes suitable for use in a number of health-related information environments; - declares the semantics of these datatypes using the terminology, notations and datatypes defined in ISO/IEC 11404, thus extending the set of datatypes defined in that standard; - provides UML definitions of the same datatypes using the terminology, notation and types defined in Unified Modelling Language (UML) version 2.0; - specifies an XML (Extensible Mark-up Language) based representation of the datatypes.