# Language Reference Sets

## Purpose

A [900000000000506000 |Language type reference set|](http://snomed.info/id/900000000000506000) supports the representation of language and dialects preferences for the use of particular descriptions. The most common use case for this type of reference set is to specify the acceptable and preferred terms for use within a particular country or region. However, the same type of reference set can also be used to represent preferences for use of descriptions in a more specific context such as a clinical specialty, organization or department.

## Data structure

A Language reference set is a Component reference set that is used to indicate which descriptions contain terms that are acceptable or preferred in a particular language or dialect. Its structure is shown in the following table.

**Reference Set Types in the Metadata Hierarchy (2018-01-31)**

<table data-full-width="true"><thead><tr><th width="208.015625">Field</th><th width="94.0859375">Data type</th><th width="605.4929809570312">Purpose</th><th width="89.25390625">Mutable</th><th width="144.0390625">PK*</th></tr></thead><tbody><tr><td>id</td><td>UUID</td><td><p>A 128 bit unsigned Integer, uniquely identifying this reference set member.</p><p>Different versions of a <em>reference set member</em> share the same id but have different effectiveTime. This allows a <em>reference set member</em> to be modified or made inactive (i.e. removed from the active set) at a specified time.</p></td><td><strong>NO</strong></td><td><strong>YES</strong><br>(Full /Snapshot)</td></tr><tr><td>effectiveTime</td><td>Time</td><td><p>The inclusive date or time at which this version of the identified reference set member became the current version.</p><p><strong>Note</strong>: In distribution files the effectiveTime should follow the short ISO date format (<em>YYYYMMDD</em>) and should not include the hours, minutes, seconds or timezone indicator.</p><p>The current version of this reference set member at time <em>T</em> is the version with the most recent effectiveTime prior to or equal to time <em>T</em>.</p></td><td><strong>YES</strong></td><td><p><strong>YES</strong><br>(Full)</p><p>Optional (Snapshot)</p></td></tr><tr><td>active</td><td>Boolean</td><td><p>The state of the identified reference set member as at the specified effectiveTime .</p><p>If active = 1 (true) the reference set member is part of the current version of the set, if active = 0 (false) the reference set member is not part of the current version of the set.</p></td><td><strong>YES</strong></td><td><strong>NO</strong></td></tr><tr><td>moduleId</td><td>SCTID</td><td><p>Identifies the SNOMED CT module that contains this reference set member as at the specified effectiveTime.</p><p>The value must be a subtype of <a href="http://snomed.info/id/900000000000443000">900000000000443000 |Module (core metadata concept)|</a> within the metadata hierarchy.</p></td><td><strong>YES</strong></td><td><strong>NO</strong></td></tr><tr><td>refsetId</td><td>SCTID</td><td><p>Identifies the reference set to which this reference set member belongs.</p><p>In this case, a subtype descendant of: <a href="http://snomed.info/id/900000000000506000">900000000000506000 |Language type|</a></p></td><td><strong>NO</strong></td><td><strong>NO</strong></td></tr><tr><td>referencedComponentId</td><td>SCTID</td><td>A reference to the SNOMED CT component to be included in the reference set.<br>Refers to the description to which the acceptability value is being applied.</td><td><strong>NO</strong></td><td><strong>NO</strong></td></tr><tr><td>acceptabilityId</td><td>SCTID</td><td>A subtype of <a href="http://snomed.info/id/900000000000511003">900000000000511003 |Acceptability|</a> indicating whether the description is acceptable or preferred for use in the specified language or dialect .</td><td><strong>YES</strong></td><td><strong>NO</strong></td></tr></tbody></table>

{% hint style="info" %}
PK\* indicates if the attribute is part of the primary key for that file/table.
{% endhint %}

***

## Language Reference Rules and Guidance

In a Language reference set:

* No more than one description of a specific description type associated with a single concept may have the acceptabilityId value [900000000000548007 |Preferred|](http://snomed.info/id/900000000000548007) .
* Every active concept should have one preferred synonym in each language.
  * This means that a language reference set should assign the acceptabilityId [900000000000548007 |Preferred|](http://snomed.info/id/900000000000548007) to one synonym (a description with typeId value [900000000000013009 | synonym|](http://snomed.info/id/900000000000013009) ) associated with each concept .
  * This description is the preferred term for that concept in the specified language or dialect.
* Any description which is not referenced by an active row in the reference set is regarded as unacceptable (i.e. not a valid synonym in the language or dialect ).
  * If a description becomes unacceptable, the relevant language reference set member is inactivated by adding a new row with the same id, the effectiveTime of the change and the value active=0.
  * For this reason there is no requirement for an "unacceptable" value.

## Metadata

The following metadata supports this reference set :

**Language References Sets in the Metadata Hierarchy**

> [900000000000454005 |Foundation metadata concept|](http://snomed.info/id/900000000000454005)\
> [900000000000506000 |Language type|](http://snomed.info/id/900000000000506000)\
> [900000000000507009 |English|](http://snomed.info/id/900000000000507009)\
> [900000000000508004 |GB English|](http://snomed.info/id/900000000000508004)\
> [900000000000509007 |US English|](http://snomed.info/id/900000000000509007)

***

The immediate children of [|Language type|](http://snomed.info/id/900000000000506000) will represent languages. This level may be used to represent the "formal approved" language, where a language authority is formally recognized. In most cases, this level will not identify a specific reference set. Subtype of the language level are used to represent different dialects, national or regional variants.

## Reference Set Descriptor and Example Data

{% hint style="info" %}
**Notes on the tables used to show descriptors and examples**

The reference set example tables on this page have been revised as follows to aid clarity and understanding:

* The first four columns which are present in all release files are not shown. The omitted columns (id, effectiveTime, active, moduleId) are used in the same way in all referenced sets to support identification, versioning and packaging. They do not directly affect the specific features of a particular reference set or reference set type.
* Reference set columns that contain SNOMED CT identifiers are expanded to show details of the concept or description referenced by that identifier. In some cases, the term is shown in the same column using the expression syntax, in other cases an additional column with a name suffix '\_term' has been added. In the standard reference set files only the identifier is present in the column and there is no added column for the term. When using reference sets, the term and other details of the component are looked up from the relevant component release files.
  {% endhint %}

#### Language Reference Descriptor

The table below shows an example of the descriptor for a specific reference sets that follows the [|Language type reference set|](http://snomed.info/id/900000000000506000) pattern.

**Refset Descriptor rows for a language reference set**

<table data-full-width="true"><thead><tr><th width="228.25863647460938">refsetId</th><th width="237.31329345703125">referencedComponentId (Referenced component)</th><th width="240.94610595703125">attributeDescription (Attribute description)</th><th width="262.35308837890625">attributeType (Attribute type)</th><th width="102.7249755859375">attributeOrder (Attribute order)</th></tr></thead><tbody><tr><td><a href="http://snomed.info/id/900000000000456007">900000000000456007 |Reference set descriptor|</a></td><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/900000000000510002">900000000000510002 |Description in dialect|</a></td><td><a href="http://snomed.info/id/900000000000462002">900000000000462002 |Description type component|</a></td><td>0</td></tr><tr><td><a href="http://snomed.info/id/900000000000456007">900000000000456007 |Reference set descriptor|</a></td><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/900000000000511003">900000000000511003 |Acceptability|</a></td><td><a href="http://snomed.info/id/900000000000461009">900000000000461009 |Concept type component|</a></td><td>1</td></tr></tbody></table>

***

#### Language Reference Set Examples

**Sample content from the US English language reference set**

<table data-full-width="true"><thead><tr><th>refsetId</th><th>referencedComponentId (Description)</th><th>accetabilityId (Accetability in dialect)</th></tr></thead><tbody><tr><td><a href="http://snomed.info/id/900000000000509007">900000000000509007 |US English|</a></td><td><a href="http://snomed.info/id/42969009">42969009 |Cauterization of skin {id:71693012}|</a></td><td><a href="http://snomed.info/id/900000000000548007">900000000000548007 |Preferred|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000509007">900000000000509007 |US English|</a></td><td><a href="http://snomed.info/id/42969009">42969009 |Fulguration of subcutaneous tissue {id:71695017}|</a></td><td><a href="http://snomed.info/id/900000000000549004">900000000000549004 |Acceptable|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000509007">900000000000509007 |US English|</a></td><td><a href="http://snomed.info/id/80146002">80146002 |Appendectomy {id:132967011}|</a></td><td><a href="http://snomed.info/id/900000000000548007">900000000000548007 |Preferred|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000509007">900000000000509007 |US English|</a></td><td><a href="http://snomed.info/id/80146002">80146002 |Excision of appendix {id:132972019}|</a></td><td><a href="http://snomed.info/id/900000000000549004">900000000000549004 |Acceptable|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000509007">900000000000509007 |US English|</a></td><td><a href="http://snomed.info/id/271737000">271737000 |Anemia {id:406636013}|</a></td><td><a href="http://snomed.info/id/900000000000548007">900000000000548007 |Preferred|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000509007">900000000000509007 |US English|</a></td><td><a href="http://snomed.info/id/271737000">271737000 |Absolute anemia {id:406640016}|</a></td><td><a href="http://snomed.info/id/900000000000549004">900000000000549004 |Acceptable|</a></td></tr></tbody></table>

***

**Sample content from the GB English language reference set**

<table data-full-width="true"><thead><tr><th>refsetId</th><th>referencedComponentId (Description)</th><th>accetabilityId (Accetability in dialect)</th></tr></thead><tbody><tr><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/42969009">42969009 |Cauterisation of skin {id:493493018}|</a></td><td><a href="http://snomed.info/id/900000000000548007">900000000000548007 |Preferred|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/42969009">42969009 |Fulguration of subcutaneous tissue {id:71695017}|</a></td><td><a href="http://snomed.info/id/900000000000549004">900000000000549004 |Acceptable|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/80146002">80146002 |Excision of appendix {id:132972019}|</a></td><td><a href="http://snomed.info/id/900000000000549004">900000000000549004 |Acceptable|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/80146002">80146002 |Appendicectomy {id:132973012}|</a></td><td><a href="http://snomed.info/id/900000000000548007">900000000000548007 |Preferred|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/271737000">271737000 |Anaemia {id:406638014}|</a></td><td><a href="http://snomed.info/id/900000000000548007">900000000000548007 |Preferred|</a></td></tr><tr><td><a href="http://snomed.info/id/900000000000508004">900000000000508004 |GB English|</a></td><td><a href="http://snomed.info/id/271737000">271737000 |Absolute anaemia {id:406641017}|</a></td><td><a href="http://snomed.info/id/900000000000549004">900000000000549004 |Acceptable|</a></td></tr></tbody></table>

***

{% hint style="info" %}
In the above examples, [80146002 | Excision of appendix|](http://snomed.info/id/80146002) is acceptable in both US and GB English. However, [80146002 | Appendectomy|](http://snomed.info/id/80146002) is preferred in US English and [80146002 | Appendicectomy|](http://snomed.info/id/80146002) is preferred in GB English.
{% endhint %}

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