Extensions Practical Guide

Search

SNOMED CT Document Library

    Loading...

Page tree

  

Purpose

The main reasons for adding descriptions in an extension are:

  • To translate SNOMED CT into another language
  • To add terms that are preferred or accepted within a local setting, for example
    • Common clinical terms that facilitate searching for concepts
    • Patient friendly terms
  • To support the creation of new concepts in the extension, which each require at least two descriptions

Principles

Overview

As depicted in Figure 5.4.3.1-1, a description in an extension may refer to any concept in the same extension (Extension B), any concept in a module upon which the extension modules depend (Extension A), or any concept in the International Edition.


Figure 5.4.3.1-1: Descriptions can reference concepts in other modules on which the extension modules depend

Note that the green and orange triangles pointing to the purple circle represent a situation in which a description is added to an extension that describes an international concept. These extension descriptions supplement the descriptions that are already part of the International Edition.

Adding Descriptions for a New Concept

Descriptions in SNOMED CT are represented in a description file. At least two descriptions must be created for each new concept in an extension: 

  • A description of type | Fully specified name|  (FSN)
    • Note that all extension producers should create an unambiguous FSN in US English for each new concept. Additional FSNs may also be created to support other languages and dialects.
  • A description of type | Synonym| , in either English or an alternative language

The acceptability of new descriptions must be specified in a language reference set.

Adding Fully Specified Names

The following principles apply to adding FSNs in an extension.

  • There may be more than one active description with a typeId of | Fully specified name|  (FSN).
    • However, only one FSN should be marked as preferred for use in a given language or dialect by a specific Language Reference Set.
  • Every extension concept must have an unambiguous FSN in US English.
    • The US English FSN is the point of reference for the meaning of all concepts in the SNOMED CT International Edition.
    • The US English FSN is used to facilitate sharing and to resolve potential issues related to the interpretation of the meaning.
  • Extensions producers are permitted to create a FSN in each of their native languages.
    • This means that a non-English FSN may be marked as the preferred FSN in a specific language reference set in the extension.
    • Consequently, a concept may have more than one FSN. However, only one may be preferred in a specific language reference set. 
    • Where a concept has only one active description with a typeId of | Fully specified name|  across all language codes within a release, then that description can be assumed to be the FSN for all languages and dialects, and need not be explicitly included in every language reference set.

Adding Synonyms

  • Unlike FSNs, synonyms are not necessarily unique between concepts, as the same term can be used to describe more than one concept.
  • The preferred term is the synonym marked as preferred for use in the Language Reference Set for a given language or dialect.
    • There must be at least one description with a typeId of  | Synonym|  and an acceptabilityId value of | Preferred|  for each concept associated with a description in a given language reference set.

Adding Descriptions to an Existing Concept

When a description is created in an extension, as part of a translation or to provide a localized synonym for an existing concept, a new row should be added in the relevant language reference set to indicate whether the description is  | Preferred|  or | Acceptable|  in the given language or dialect. 

Process

The table below provides a summary of the process to follow when adding new descriptions to an extension. 

File TypeProcess
Description



A new row which represents the new description is added to the description file.

The attributes of the new description are set as follows:

  • id is set to a new descriptionId allocated within the extension namespace
  • effectiveTime is set to the date the extension will be published
  • active is set to 1 to indicate that the new description will be active at the time of publication
  • moduleId is set to the conceptId of a module that is managed by the extension producer
  • conceptId is set to the id of the concept to which this description applies
  • languageCode is set to the two character code of the language in which this term was authored
  • typeId is set to indicate the type of the description
  • term is set to the string of characters used to describe the given concept
  • caseSignificanceId is set to indicate the case significance of the term
Language Reference Set

A new row (or member) is added to each relevant language reference set.

The attributes of the new language reference set member are set as follows:

  • id is set to a unique automatically-generated UUID
  • effectiveTime is set to the date the extension will be published
  • active is set to 1 to indicate that the new member will be active at the tiem of publication
  • moduleId is set to the conceptId of a module that is managed by the extension producer
  • refsetId is set to the conceptId of the language reference set to which the member is added
  • referencedComponentId is set to the descriptionId of the new description
  • acceptability is set to indicate the acceptability of the new description in the relevant language or dialect
    • Value is either | Preferred|  or  | Acceptable|
    • Each concept may have only one preferred FSN and one preferred synonym in each language reference set
Feedback
  • No labels