Appendix A: Overview of Reference Set Types

Content Reference Sets

Table: Overview of reference set types and example use cases, as described in the international Release of SNOMED CT

Reference Set Type	Description	Example Use Cases
Simple reference set	Allows a set of components to be specified for inclusion or exclusion for a specified purpose	Constrain values available in clinical data entry templates. (E.g. define pick lists, constrain searches etc.) Specify values accepted for communication purposes in specific elements in a communication message
Ordered reference set	Allows a collection of components to be defined with a specified given a priority ordering	Alternative navigation hierarchies. Specify a preferred order of concepts/descriptions in pick lists
Attribute value reference set	Allows a value from a specified range to be associated with a component	This reference set type can be used for many different purposes that are related to both content and technical use cases. E.g. to specify why a concept or description has been inactivated
Simple map reference set	Allows representation of simple maps between SNOMED CT concepts and values in other code systems.	Appropriate where there is a close "one-to-one" mapping between SNOMED CT concepts and coded values in another code system.
Complex and Extended Map reference sets	Allows representation of simple complex maps between SNOMED CT concepts and values in other code systems	Enables representation of maps where each SNOMED CT concept may map to one or more codes in a target scheme, or where the correlation of each map should be specified
Language reference set	Supports the representation of language and dialects preferences for the use of particular descriptions	Used to specify the acceptable and preferred terms for use within a particular country or region. Can also be used to represent preferences for use of descriptions in a more specific context such as a clinical specialty, organization or department
Query specification reference set	Allows a serialized query to represent the membership of a subset of SNOMED CT components	Used to represent Intentional definitions of reference sets. Constrain values available in clinical data entry templates, as part of a terminology binding
Annotation reference set	Allows text strings to be associated with components for any specified purpose	E.g. linking a SNOMED CT component to a url, e.g. for linking to a clinical guideline
Association reference set	Represents a set of unordered associations of a particular type between components	Used to associate inactive concepts with active concepts that can serve as potential replacements for the inactivated concepts

Reference Sets for Technical Use

Table: Overview of reference set types and example use cases, as described in the international Release of SNOMED CT

Reference Set Type	Description	Example Use Cases
Module dependency reference set	Represents dependencies between different SNOMED CT release modules	The Module Dependency reference set is used to ensure that all dependencies are satisfied when importing data
Description format reference set	Specifies the text format and maximum length of each supported description type	Specify new, localized description formats to be used in an Extension
Reference set descriptor reference set	Represents the format of all reference sets included in a particular release	Specify new, customized reference set formats to be used in an Extension

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