Available Formats

The NCTS terminology products are available in a variety of formats to improve accessibility and adoption by a broad range of users spanning business, clinical and technical.

This section provides an overview of each format type including what it contains, features, limitations and typical use cases to assist users in determining their most suitable format.

SNOMED CT-AU RF2 Release

Release Format 2 (RF2) is the current release format developed by SNOMED International to support the creation of reference sets.

What is included?

  • A Full release is a complete view including every version of every SNOMED CT-AU component ever released. It allows an implementer to fully populate a database which can be used to view the state of SNOMED CT-AU at any given point in time (e.g. before or after any particular release). Therefore, a Full release is ideal for initial installation of SNOMED CT-AU content or a complete replacement of an earlier installation.
  • A Delta release consists of only the entries that have changed from the previous release. It can simply be added to an existing database containing the Full view of the previous version. This provides a lightweight way to update SNOMED CT-AU without changing existing content. It is particularly useful, as it provides a simple way to apply updates to individual extensions without any impact on the International release or any other installed extension.
  • A Snapshot release provides the latest state (active or inactive) of every SNOMED CT-AU component at the time that the release is available. It is useful for those implementers who do not need to provide access to earlier versions.

What are the benefits?

A consistent and unambiguous versioning mechanism is critical for the effective maintenance and implementation of SNOMED CT-AU. The RF2 approach to versioning simplifies the task of maintaining SNOMED CT-AU content. RF2 also provides a simple mechanism that allows implementers to access and compare different versions in real time. As all the distributions represent versioning in exactly the same way, it is no longer necessary to write table-specific code for processing updates. Instead common code can be used to provide version-specific views of concepts, descriptions, relationships and reference sets that represent subsets, maps and language preferences.

The RF2 versioning mechanism allows application developers and implementers to:

  • Unambiguously identify which version of SNOMED CT-AU is in current use;
  • Determine what changed between two versions or between two points in time;
  • Determine what will change when a new version is installed;
  • Evaluate the impact of version updates on a running system; and
  • Allow dependencies between different releases and components to be recognised and resolved.

Are there any limitations?

At this point in time there are no limitations for implementation beyond a vendor’s capability to deal with the size and scope of the terminology.

What is the common use case?

For implementers who wish to use the full power of SNOMED CT-AU to enable features such as complex querying or using the data for secondary use.

How do I access the files?

Registered users can download the RF2 files by selecting SNOMED CT-AU > Release Bundles from the ACCESS tab.

FHIR® Resources

The HL7 Fast Health Interoperability Resources (FHIR®) standard is an interoperability specification (and eventual standard) for exchanging healthcare information based on proven web technologies and the extensive experience of HL7 in standards development. It defines a set of resources that may be represented using XML or JSON formats during exchange.

Included in FHIR is the specification of a terminology service. A FHIR terminology service provides a set of functions which relies on code system, value set and concept map resources. Each of these resources support particular uses. A code system resource can define a set of codes and their meanings, a value set resource specifies a set of codes belonging to one of more code systems, and a concept map states relationships from one set of concepts to one or more other concepts.

Learn more about FHIR here https://www.hl7.org/fhir/terminology-service.html

What is included?

The NCTS makes available national FHIR Resources through a registry. The registry currently allows users to browse or search FHIR value set representations of active SNOMED CT-AU simple type reference sets and their metadata.

What are the benefits?

Terminology use with FHIR resources leverages the benefits of the FHIR specification. These are described here https://www.hl7.org/fhir/summary.html

In addition to these, FHIR provides a mechanism to interact with and represent many different code systems in a similar way. In enables simplification of both implementation and the management of terminology.

Are there any limitations?

The limitations of using FHIR Resources for terminology are bound to the specification itself. Representations and interactions are defined by FHIR, thereby restricting the scope of terminology use.

It may not be suitable for those who wish to undertake rich analytics using the semantics of code systems not exposed by FHIR.

What are the common use cases?

Within a terminology service, FHIR resources can be used to:

  • present to a user a list of search results matching certain criteria;
  • validate a code belongs to specified set of codes (i.e. value set);
  • translate a coded value to a code in another code system; and
  • look up the details of individual codes.

How do I access the files?

Registered users can download the FHIR value set representations by selecting SNOMED CT-AU > Reference Sets from the ACCESS tab. They may also be obtained via the Integration Interface of the National Terminology Server.

TSV Value Sets

TSV (Tab Separated Values) is a table-oriented file format that is easily imported into common spreadsheet applications.

What is included?

These downloads are a convenient form of simple type reference set and value set content, containing precomputed values for Concept ID and the related Fully specified Name, Preferred Term and Synonym descriptions for each concept. The downloaded file will contain all active members of the value set. Inactive historical members of the set are omitted.

What are the benefits?

These downloads are a convenient form of value set content, well suited for inspection and review by clinicians and other non-technical users.

Are there any limitations?

TSV value sets only contain limited information in comparison to other available formats.

What is the common use case?

For implementations that do not require the full power of the terminology to be implemented and can only consume limited amounts of data.

How do I access the files?

Registered users can download the TSV value sets by selecting SNOMED CT-AU > Reference Sets from the ACCESS tab.