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Native SNOMED CT RF2 files

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We distribute native SNOMED RF2 files for software developers who would like to integrate SNOMED CT within their existing infrastructure. This enables customisation and sophisticated queries but requires advanced technical expertise with SNOMED CT. Developers will gain a comprehensive understanding of file formats, relationship types, extension mechanisms and the interaction between the terminology and the information model.

What is the RF2 format?

Release Format 2 (RF2) is the current release format developed by SNOMED International. It supports terminology versioning and the creation of reference sets. These are published as tab-delimited text files encoded by Unicode UTF-8.

A sample schema is provided as a learning tool to understand the release format in a relational database environment. Implementers should not take the sample as the suggested approach for their implementation.

This entity-relationship diagram shows the schema design for the core SNOMED CT tables within the sample scripts for SNOMED CT-AU

What are the benefits of using the RF2 files?

  • check mark Optimally designed for relational database management systems.
  • check mark Compatible with non-relational (e.g. document- oriented) databases but requires more effort in transformation.
  • check mark Greater flexibility when using SNOMED CT for research and advanced analytics.
  • check mark Easier access to complex reference sets such as AMT concrete domain reference sets.

How is it packaged?

A Full release is a complete view including every version of every SNOMED CT-AU component ever released. It can be used to view the state of SNOMED CT-AU at any given point in time but should not be exposed to clinicians for data entry at the point of care. 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.

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 implementers who do not need to provide access to earlier terminology versions.

The Snapshot release is a good option for most clinical information systems, filtering on active components for data entry and but also containing inactive components for data validation and retrieval. Applications that query historical patient records may require access to the Full release to understand the meaning of data captured at a given point in time.

Visit SNOMED International for more guidance about release type options.

See also:

Common tasks when working with native SNOMED RF2 files

Download SNOMED CT-AU release bundles