CTS2 provides services to manage the resources listed below. Each specification contains sections, and the sections provide functional service definitions—for read, query, history, and maintenance services for all structural resources, and additional update, temporal, and specialized services for some. Each resource description below also indicates the CTS2 section in which it is specified.
For more detail about how CTS2 is derived from the HL7 SFM, see these traceability pages.
Code System Catalog – a list of code systems with defined metadata. Code System Catalog services publish information about what sort of terminological resources are available, who maintains them, what they are intended to be used for, how often they are released, what copyrights pertain to them, etc. CTS2 Section: Code System and Code System Version Catalog Services
Code System Version Catalog – a list of versions of code systems with defined metadata. Implement Code System Version Catalog services to provide information about specific versions of code systems – when they were released, what format they are in, when they were intended to become active, which version they replace, etc. CTS2 Section: Code System and Code System Version Catalog Services
Entity Description – identifiers and descriptions for a member of a value set or code system; i.e., a concept, term, association, class, predicate, property, or individual (e.g., state or province). The entity description service focuses on the lexical aspect of entity identifiers – providing access to the designations, definitions, descriptions, examples, usage notes and other artifacts used to represent the meaning of the entity to human consumers. Implement this section to publish information about the codes described in various versions of code systems along with their intended meanings. CTS2 Section: Entity Description Services and Association Services
Association – sets of “semantic” assertions about entity identifiers, in which the entity identifier may play the role of subject, predicate (verb) or object in the assertions. This area represents the formal machine interpretable aspects of code systems; implement this section to support classification, reasoning or other computational logic systems built on terminological content. CTS2 Section: Entity Description Services and Association Services
Value Set Catalog – a list of value sets with defined metadata. Value Set Catalog services publish information about these collections such as who created them, who maintains them, what is their purpose, what code systems do they depend on, how they are updated, etc. CTS2 Section: Value Set Services
Value Set Definition – information specifying how a value sets is constructed. A value set definition can be a simple enumeration of its elements, or it can contain instructions about how the elements are assembled from aspects of entity descriptions and associations. A value set definition may be coupled to a specific version of a code system, or it may be defined in a way that they could be applied to different versions, potentially with different results. Implement this section to publish the rules on the construction of value sets. CTS2 Section: Value Set Services
The value set definition section includes an optional sub- section (Resolved Value Set) that enables the publication, loading and use of the results of applying value set definitions. Services would implement this section when they needed to consume and use value sets without having access to the underlying code systems. CTS2 Section: Value Set Services
Concept Domain Catalog – a list of abstract “concept domains” that each represent a collection of possible meanings. Concept domains are intended to represent the intended meaning of a data element (a field on a form, a column in a database, a field in a message, etc.). The CTS2 specification focuses on enumerated concept domains – fields that represent discrete collections of “meanings”, each of which is represented by a permissible value. Implement this section to provide a list of generic fields that would be used in data interchange. CTS2 Section: Concept Domain and Concept Domain Binding Services
Concept Domain Binding – an association between a concept domain and a value set intended to provide valid values for the domain in a particular context. CTS2 Section: Concept Domain and Concept Domain Binding Services
Map Catalog – a list of cross-maps or rule sets for transforming values from one value set or code system into values from another. Map Catalog services publish information about which rule sets are available, which code systems or value sets they map between, their intended purpose, how often they are published, what formats they are in, etc. CTS2 Section: Map Catalog and Map Version Services
Map Version – an instance of a map, including the specific value set definitions that and code systems that they are based on and the actual rules. Implement this section to publish the content of maps. This section includes an optional sub-section (Map Resolution) that provides access to the machine-aided interpretation of map versions – a service that does the actual map transformation. CTS2 Section: Map Catalog and Map Version Services
Statement – a bridge between the information contained in the various sections described above and the actual assertions made by the information providers. Implement this section to provide additional provenance about assertions made in catalogs or resource versions including what was actually said, how it mapped to the CTS2 service representation, the provenance of the assertion, etc. Statement is also intended to act as a bridge between the structured CTS2 model and simple subject/predicate/target systems as represented by OWL and RDF.