Organizing members of a subset into a specific order can be useful to meet certain implementation requirements, such as displaying drop down lists for data entry or search results. Members of a subset can be ordered in a variety of automated ways, including displaying the shortest term that matches the search term first, alphabetically, or randomly. However, when the required order cannot be automatically computed, it may be necessary to specify an order for each subset member. Ordered lists of SNOMED CT components (typically concepts or descriptions) can be represented using an Ordered Reference SetFor more information about ordering SNOMED CT components on a user interface, please refer to the SNOMED CT Search and Data Entry Guide.

Requirements for an ordered list of components

RequirementDescriptionExample UsesReference Set
An ordered list of concepts

A subset consisting of references to specific SNOMED CT concepts, i.e. a set of . Additionally, each subset member is assigned a specific order, which enables prioritization.

  • Presenting concepts in an order that is rational or helpful for a particular purpose irrespective of the term displayed
  • Making it easier to find concepts that are most commonly used in a particular specialty, department or data entry scenario
Ordered Reference Set
An ordered list of descriptions

A subset consisting of references to specific SNOMED CT descriptions, i.e. a set of , where each included member identifies a description. Additionally, each subset member is assigned a specific order, to enable ordering or prioritizing the members.

  • Presenting terms in an order that is rational or helpful for a particular purpose in user interface controls including:
    • Simple lists
    • Drop down lists
    • Popup menus
  • Ordering search results 
Ordered Reference Set 

For more detailed use case examples, please refer to the following sections: