Reference sets use a range of different attributes depending on the reference set type. While a detailed discussion of all reference set attributes is outside the scope of this document, this section briefly reviews some of the key attributes. Please refer to Reference Set Types in the Practical Guide to Reference Sets for more information on reference set types and their specific attributes. Please refer to 5.4.5 Authoring Reference Sets and 5.4.6 Authoring Reference Set Members for more information on the principles and processes for authoring reference sets and their members.
All reference sets share six common attributes:
The following subsections explain how these attributes are used in an extension.
The first attribute of every extension reference set member is 'id'. Unlike the id of a SNOMED CT component, the id of a reference set member is a UUID (Universally Unique Identifier). UUIDs are 128-bit unsigned integers, which are uniquely generated using widely available algorithms. This avoids the need to track the issuing of SCTIDs for thousands of reference set rows. When used in a reference set, the id identifies the reference set member or row.
The second attribute of every extension reference set member is 'effectiveTime'. This attribute specifies the date on which the specific version of the reference set member was released, using the ISO 8601 YYYYMMDD format. When a reference set member is added or modified in an extension, the effectiveTime of the member version will match the version date of the release.
The third attribute of every extension reference set member is 'active'. This attribute specifies whether or not the specific version of the reference set member is active at the given effectiveTime. The data type of this attribute is Boolean, with a value of "1" indicating that the member is active at the given effective time and a value of "0" indicating that the member is inactive at the given effectiveTime. New reference set members in an extension will use an active value of "1".
The fourth attribute in every extension reference set member is 'moduleId'. This attribute specifies the module in which the member is being maintained at the given effective time. The value of this attribute is the SCTID of a module concept that is created and maintained by the extension producer. Please refer to 4.2.1 Module Definition for more information on this topic.
The fifth attribute in every extension reference set member is 'refsetId'. This attribute refers to the id of the reference set concept that is used to represent the meaning of the reference set to which the given member belongs. The reference set concept must be a subtype of |Reference set|. The descriptions associated with this concept help to name the reference set. For more information, please refer to 184.108.40.206 Reference Set Example.
The sixth attribute of every extension reference set member is 'referencedComponentId'. This attribute uses a SCTID to identify the component that is referenced by this member of the reference set. For example, the referencedComponentId may refer to a member of a subset represented by a |Simple type reference set|, to the description whose acceptability is being defined in a |Language type reference set|, or to the source of map in a |Simple map type reference set| ..