Introduction

SNOMED CT terminology provides a common language that enables a consistent way of indexing, storing, retrieving, and aggregating clinical data across specialties and sites of care.

The International Health Terminology Standards Development organisation (IHTSDO^®), trading as SNOMED International, maintains the SNOMED CT technical design, the content architecture, the SNOMED CT content (includes the concepts table, the descriptions table, the relationships table, a history table, and ICD mappings), and related technical documentation.

The SNOMED CT Irish Extension - packages these components for release every April and October, to be used with the latest SNOMED CT International Edition release.

The same content can be viewed online using the SNOMED CT browser, and eHealth Ireland website

Background

This document provides a summarized description of the content changes included in the April 2025 Production release of the SNOMED Clinical Terms^® Managed Service Ireland Extension package.

It will also include technical notes detailing the known issues which have been identified (should any of these exist). These are content or technical issues where the root cause is understood, and the fix has been discussed and agreed, but has yet to be implemented.

This Ireland Extension package is dependent upon, and should therefore be consumed in conjunction with the SNOMED CT® September 2024 International Edition release.

2.1 Scope

This document is written for the purpose described above and is not intended to provide details of the technical specifications for SNOMED CT or encompass every change made during the release.

Content Development Activity

Summary

Content from the SNOMED CT® March 2025 International Edition release has been included, alongside additional components for use in Ireland. 

This extension contains concepts, relationships and reference sets for healthcare professionals. 

New and Updated Content

This is the 10th SNOMED CT Irish Edition Production release.

IE National Drug Extension:

The National Drug Extension continues to be developed. This includes content development across the SNOMED International Drug Model and the Irish Drug Extension.

Please note that content development work is occurring in relation to medicinal products in the national SNOMED Irish Drug Extension.

This release contains concepts in the Pharmaceutical / biologic product (product), Qualifier value (qualifier value), and Substance (substance) hierarchies related to this ongoing work. Due to the volume of content, this will occur across several releases and release notes will be updated when this work reaches stability/maintenance levels. Ahead of this, please note that content in the Irish drug extension should be considered partial against the range of medicinal products available to be used in clinical care in Ireland. 

IE National Drug Extension – April 2025 Summary

New and updated content

Concept statistics

The SNOMED Irish National Release Centre published 16 new concepts, and these are available in the Irish Extension April 2025  release.

Table 1. New concepts in the Irish Edition April release

1 new refsets was developed 

3 refsets were updated

New Authoring by Irish NRC

Reference Set changes

Table 3.3 Content Sent from Irish NRC to SNOMED International for promotion

Table 1.3 Content sent from Irish NRC to SNOMED International for authoring

4 Technical notes

4.1 Known Issues

Known Issues are content or technical issues where the root cause is understood, and the resolution has been discussed and agreed but has yet to be implemented.  This can be due to a number of reasons, from lack of capacity within the current editing cycle, to the risk of impact to the stability of SNOMED CT if the fix were to be deployed at that stage in the Product lifecycle.  

For the SNOMED CT Managed Service - Ireland Extension Release, no Known Issues were identified, 

4.2 Resolved Issues

Resolved Issues are those where the resolution has been discussed and agreed, and has been implemented in time for this release. 

4.3 Notice of changes to the International Edition Release Schedule

As you may already know SNOMED International have transitioned to a monthly delivery schedule for the International Edition of SNOMED CT. The move towards more frequent releases of SNOMED CT will realize several benefits, including:

• The potential to be able to get content changes into the terminology in a shorter time frame.

• The fostering of better interoperability, as a result of entities being able to consume release content that is more aligned with other organizations.

• The prevention of circular dependencies that occur in longer projects, due to the move towards smaller, more manageable authoring projects.

• More automated validation services, as a result of the inherent removal of the Alpha/Beta stages in the Release cycle.

Whilst most users will continue unaffected (as they can simply continue to download the releases every 6 months as always), this transition will necessarily involve a few changes to process/packages:

• Delta files have been removed from both International and Managed Service release packages, including the Ireland Extension.  A Delta Generation service will be provided for those who need it. The Delta Generation Tool allows users to create their own Delta between two fixed release dates - you can find it here:

  • https://github.com/IHTSDO/delta-generator-tool/releases

• The ICD-O/ICD-10 Maps will continue to be published in each Monthly International Edition release package (in line with that month's content) for the foreseeable future, unless we experience issues with the new process in Production, and they need to be removed at a later date.

The first monthly Release of the SNOMED CT International Edition was published on the 28th February 2022 with the Delta files having been removed, and therefore they will be removed from the Ireland Extension from the October 2022 Release onwards.

Please note - While the SNOMED CT International Edition is moving to monthly releases, the Ireland Extension of SNOMED CT will remain on the current bi-annual release schedule of April and October for 2024.

4.4 Changes for October 2025

Monthly Releases

The NRC is moving to monthly releases after October 25 and as a result of preparation for this, please be aware that the 21st October 2025 release will contain "multiple/additional" effective times between April and October. 

Refset naming changes

The refset file name will change from October 2025 with an example below

 IE Release the refset filename for "74921000220101 |Antimicrobial Stewardship Performance Indicator Measurement System Apims DataSet reference set|" would change from:

• "der2_Refset_AntimicrobialStewardshipPerformanceIndicatorMeasurementSystemApimsDataSetSimpleRefsetFull_IE1000220_20250421.txt"

•  

  • to:

• "der2_Refset_74921000220101SimpleRefsetFull_IE1000220_20250421.txt"

4.5 Notice of changes to the IE Extension Release package

In line with the refined implementation of Annotations, we are updating all Extensions in order to align them with the updated version of the refsets in the International Edition Release package (which were first published in June 2024).

The languageCode field was specified as the two characters of ISO-639-1 code for the language of the annotation text. The change includes support for specifying dialect when it is applicable by adhering to RFC 5646, which allows the combination of two characters of ISO 639-1 code and two uppercase letters of country code (ISO 3166) separated by a hyphen.  The changes apply to both the Member Annotations String Value Reference Set + Component Annotation String Value reference set:

4.6 Notice of Changes for October 2025