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This section includes information about general topics related to SNOMED CT release file including:

The detailed specification of release file is provided in the two section that follow this one:

  • 3. Component Release Files Specification
    • Files that represent the main SNOMED CT components

      • Concepts

      • Descriptions

      • Relationships
  • 4. Reference Set Release Files Specification
    • Files that can be used to customize and enhance SNOMED CT by representing
      • Subsets
      • Maps to other code systems
      • Language and dialect preferences for different terms
      • Annotation of components
      • Associations between components
      • Other forms of configuration and extensibility

Related Terminology Service Documentation


Historical Note

Current and Previous Release File Formats

The standard format in which  SNOMED CT has been distributed since 2012 is known as  Release Format 2(RF2). It was developed in response to extensive feedback on the original release file format, now known as Release Format 1(RF1), in which SNOMED CT was distributed between its first release in 2002 and 2012. The SNOMED CT International Edition no longer supported or distributed in RF1. However, a conversion tool to general RF1 style files from the RF2 release files is available.

The key enhancements in RF2 were:

  • More robust and consistent version representation;
  • Inclusion of a moduleId and module dependency mechanism, which together enable modularization of releases while representing dependencies between modules;
  • Reference sets to provide an extensible and versionable way to configure  SNOMED CT. Including support for subsets, maps, annotations, alternative hierarchies, etc.;

  • Use of an added hierarchy to represent metadata about the structure of SNOMED CT itself.

In common with the earlier release format RF2 specifies files that: