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There are some pertinent questions terminology users are asking about CTS2 as it relates to available terminology servers. As you will see, this guide addresses these important questions in an attempt to steer users in the proper direction when they need to choose terminology services. If there are additional CTS2 areas where guidance would help, please let us know using the General VKC forums.

Contents of this Page

What is CTS2?

Developed through the Healthcare Services Specification Project (HSSP), Common Terminology Services Release 2 (CTS2) has been created as a standard as a shared semantic model and application programming interface (API) for the query, interchange and update of terminological content. As an API specification, CTS2 is a blueprint for building and using software which enables interoperability between CTS2 clients and services.

How is CTS2 important in vocabulary management?

Structured terminologies have some common ‘resources’ such as Code Systems, Domains, and Value Sets, and access to these resources is enabled usually through a service interface. CTS2 strives to provide a consistent representation and flexible service interfaces to structured terminologies. This enables us to accurately represent and manage a wide variety of vocabularies and other lexically-based resources in a common way.

The CTS2 Platform Independent Model (PIM) provides standard service information model and a computational model. The information model specifies the structural definition, attributes and associations of these common terminology ‘resources’ and the computational model specifies the service descriptions and interfaces needed to access and maintain structured terminologies.

The detailed description of the CTS2 PIM specifications can be found on the OMG site Exit Disclaimer logo . The following tables provide a concise look at its structure. CTS2 organizes resources in terms of coding schemes, entities and value sets and provides various functional areas to access these resources using CTS2 modules and services.

Depiction of the core model and domains of CTS2

Where can I learn more about CTS2? Are there some existing implementations or examples available?

This page helps with the choices one must make in regards to terminology services revolving around LexEVS and CTS2. In answer to the question, you may look here for other information on the VKC:

The CTS2 specification allows (and encourages) modular implementation of its model components and service interfaces. A CTS2 service instance (a particular implementation of the CTS2 specifications) may choose to implement only a subset of the model and services that it needs.

The CTS2 development team has a home site Exit Disclaimer logo built around the implementation and use of CTS2. They also provide a developer's toolkit called CTS2 Development Framework Exit Disclaimer logo for rapidly building CTS2 compliant applications.

I was planning to use LexEVS to manage my ontologies and terms? Should I switch to CTS2-based implementation? What is the difference?

LexEVS 6.0 has been very close to functionally equivalent to CTS2 specifications. Note that the LexEVS 6.0 APIs are not fully CTS2 compliant (refer to LexEVS 6.0 CTS2 API) but offer identical functionality as compared to most CTS2 services. The following table shows the functions that CTS2 specifies and whether they are available in the LexEVS 6.0 release. Please note that there are additional functions LexEVS 6.0 makes available in addition to what are listed here, but they are not listed since they do not coordinate with CTS2. To find more about those, please refer to the LexEVS 6.x Documentation.

HL7 SFM Section

Functions / Considerations

CTS2 Availability

LexEVS 6.0 Availability

6.1

Administration Operations

Used to categorize functions

Used to categorize functions

6.1.1

Import Code System

Available

Available

6.1.2

Import Code System Revision

Available

Available

6.1.3

Import Value Set Version

Available

Available

6.1.4

Import Association Version

Available

Available

6.1.5

Export Association

Available

Available

6.1.6

Export Code System Content

Available

Available

6.1.7

Change Code System Status

Available

Available

6.1.8

Register for Notification

Not Available

Available

6.1.9

Update Notification Registration

Not Available

Available

6.1.10

Update Notification Registration Status

Not Available

Available

6.2

Search / Access Operations

Used to categorize functions

Used to categorize functions

6.2.1

Code System Search / Access

All functions in category are available

All functions in category are available

6.2.1.1

List Code Systems

Available

Available

6.2.1.2

Return Code System Details

Available

Available

6.2.1.3

List Code System Concepts

Available

Available

6.2.1.4

Return Concept Details

Available

Available

6.2.1.5

List Association Types

Available

Available

6.2.1.6

Return Association Type Details

Available

Available

6.2.2

Value Set Search / Access

All functions in category are available

All functions in category are available

6.2.2.1

List Value Sets

Available

Available

6.2.2.2

Return Value Set Details

Available

Available

6.2.2.3

List Value Set Contents (Expand value set)

Available

Available

6.2.2.4

Check Value Set Subsumption

Available

Available

6.2.2.5

Check Concept Value Set Membership

Available

Available

6.2.3

Concept Domain and Usage Context Search / Access

All functions in category are available

All functions in category are available

6.2.3.1

List Concept Domains

Available

Available

6.2.3.2

Return Concept Domain Details

Available

Available

6.2.3.3

List Usage Contexts

Available

Available

6.2.3.4

Return Usage Context Details

Available

Available

6.2.3.5

List Concept Domain Bindings

Available

Available

6.2.3.5.1

Check Concept to Concept Domain Association

Available

Available

6.2.4

Association related queries

All functions in category are available

All functions in category are available

6.2.4.1

List Associations

Available

Available

6.2.4.2

Determine Transitive Concept Relationship

Available

Available

6.2.4.3

Compute Subsumption Relationship

Available

Available

6.2.4.4

Return Association Details

Available

Available

6.3

Authoring/Curation Operations

Used to categorize functions

Used to categorize functions

6.3.1

Code System Authoring/Curation

All functions in category are available

All functions in category are available

6.3.1.1

Create Code System

Available

Available

6.3.1.2

Maintain Code System Version

Available

Available

6.3.1.3

Update Code System Version Status

Available

Available

6.3.1.4

Create Code System Supplement

Available

Available

6.3.1.5

Maintain Code System Supplement

Available

Available

6.3.1.6

Create Concept

Available

Available

6.3.1.7

Maintain Concept

Available

Available

6.3.1.8

Update Concept Status

Available

Available

6.3.1.9

Create Association Type

Available

Available

6.3.1.10

Maintain Association Type

Available

Available

6.3.2

Value Set Authoring/Curation

All functions in category are available

All functions in category are available

6.3.2.1

Create Value Set

Available

Available

6.3.2.2

Maintain Value Set

Available

Available

6.3.2.3

Update Value Set Status

Available

Available

6.3.3

Concept Domain and Usage Context Authoring/Curation

All functions in category are available

All functions in category are available

6.3.3.1

Create Concept Domain

Available

Available

6.3.3.2

Maintain Concept Domain

Available

Available

6.3.3.3

Create Usage Context

Available

Available

6.3.3.4

Maintain Usage Context

Available

Available

6.3.4

Association Authoring Operations

Some functions in category are available

Some functions in category are available

6.3.4.1

Update Association Status

Available

Available

6.3.4.2

Create Association

Available

Available

6.3.4.3

Create Lexical Association between Coded Concepts

Available

Available

6.3.4.4

Create Rules Based Association between Coded Concepts

Not Available

Not Available