SNOMED CT® Release Format 1 (RF1) Guide - ihtsdo

334 | SNOMED CT Release Format 1 (RF1) Guide July 2012
There are some underlying subtleties to this table however.
The LinkedID field is only valid for:
• Navigation Subsets, where it specifies the navigational children of the subset member;
• Duplicate Terms Subsets, where it refers to the Description which is most highly prioritized.
The field MemberStatus has a different significance depending on the type of subset specified in the Subset
Table.
A brief description of the significance of the MemberStatus in each type of subset is given below.
4.4.3.2.1. Significance of MemberStatus in a Language or Realm Description Subset
The MemberStatus specifies the role of the reference Description in this Language or Realm.There are three
roles.
1 = Preferred Term
2 = Synonym
3 = Fully Specified Name
Note that the following rules apply to each Subset:
• A Description cannot be assigned the role Fully Specified Name unless its DescriptionType is also "Fully
Specified Name.";
• Only one Description of each Concept may be assigned as the Fully Specified Name;
• If no Description of a Concept is assigned the role Fully Specified Name, the FullySpecifiedName in the
Concepts Table assumes this role;
• A Description cannot be assigned the role Preferred Term or Synonym if its DescriptionType is "Fully
Specified Name.";
• One and only one Description of each Concept must be assigned the role "Preferred Term.";
• Any number of Descriptions of a Concept may be assigned the role "Synonym.".
4.4.3.2.2. Significance of MemberStatus in a Realm Concept or Context Concept Subset
The MemberStatusspecifies the priority of the Concept within the Subset, with lower numbers denoting higher
priority. The priority may be used to determine order of display. Concepts with priority status of "0" would
appear at the top of the list.
4.4.3.2.3. Significance of a MemberStatus in a navigational Subset
The MemberStatus specifies the order of the child concepts within the navigational hierarchy. This may be
used to determine the display order of children when displaying a navigational Subset.
4.4.3.2.4. Significance of MemberStatus in a Realm Relationship (for future use) or Context Description
Subset
The MemberStatus has no particular significance in these types of subsets, and will be set to the value of
"1,"meaning include this table row in the subset.
4.4.3.3. Using subset definition files (future use)
Subset definition files are the preferred way of specifying the content of subsets. The subset definition file is
a series of logical clauses, expressed as XML mark-up, which defines what should be included in the subset.
While all subsets released by the IHTSDO are currently distributed in the relational file format, there are plans
to provide these subsets as XML definition files. This method of specifying subsets has several advantages:
• It is less verbose as many members can be included by a single clause.
• It is likely to be resilient to the effects of applying updates and Extensions.
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