1 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

2 Background

This document provides a summarized description of the content changes included in the October 2023 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 2023 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.

3 Content Development Activity

3.1 Summary

Content from the SNOMED CT® September 2023 International Edition release has been included, alongside additional components for use in Ireland. 

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

3.2 New and Updated Content

New content in this release:

This is the 7th 8th SNOMED CT Irish Edition Production release.

New and updated content

Concept statistics

The SNOMED Irish National Release Centre published 156 new concepts, and these are available in the Irish Extension October 2023 release.

Table 1. New concepts in the Irish Edition October release

3 new refsets were developed 

Health Status Questionnaire Ireland Reference set

Irish national document Residential Facilities For Older People Reference set

National Rehabilitation Hospital  Allergy Nature Of Reaction Reference set

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

3.3 Inactivated concepts in Irish Edition and their replacements:

Inactive Concepts with their suggested Replacement Concepts

Breastcheck Screening Ireland Refset: 

Retraction of nipple32280000Lymphoid leukemia1172709000Lymphoid leukemia373150000pNX: Regional lymph nodes cannot be assessed (e.g., previously removed, or not removed for pathologic study) (breast)1229945006pNX373151001pN0: No regional lymph node metastasis histologically (i.e., none greater than 0.2 mm), no additional examination for isolated tumor cells (breast)1229947003pN0373156006pN1: Metastasis in 1 to 3 axillary lymph nodes, and/or in internal mammary nodes with microscopic disease detected by sentinel lymph node dissection but not clinically apparent (breast)1229951001pN1373157002pN1mi: Micrometastasis (greater than 0.2 mm, none greater than 2.0 mm) (breast)1229952008pN1mi373158007pN1mi(i+): Micrometastasis detected only by IHC (breast)1229952008pN1mi373159004pN1a: Metastasis in 1 to 3 axillary lymph nodes (at least one tumor deposit greater than 2.0 mm) (breast)1229954009pN1a373160009pN1b: Metastasis in internal mammary lymph nodes with microscopic disease detected by sentinel lymph node dissection but not clinically apparent (breast)1229955005pN1b373161008pN1c: Metastasis in 1 to 3 axillary lymph nodes and in internal mammary lymph nodes with microscopic disease detected by sentinel lymph node dissection but not clinically apparent (breast)1229956006pN1c373162001pN2: Metastasis in 4 to 9 axillary lymph nodes, or in clinically apparent internal mammary lymph nodes in the absence of axillary lymph node metastasis (breast)1229957002pN2373163006pN2a: Metastasis in 4 to 9 axillary lymph nodes (at least one tumor deposit greater than 2.0 mm) (breast)1229959004pN2a373164000pN2b: Metastasis in clinically apparent internal mammary lymph nodes in the absence of axillary lymph node metastasis (breast)1229960009pN2b373165004pN3a: Metastasis in 10 or more axillary lymph nodes (at least one tumor deposit greater than 2.0 mm), or metastasis to infraclavicular lymph nodes (breast)1229963006pN3a373166003pN3c: Metastasis in ipsilateral supraclavicular lymph nodes (breast)1229965004pN3c373167007pN3b: Tumor of breast with metastasis as per AJCC 6th Edition definition (breast)1229964000pN3b373169005pM0: No distant metastasis (breast)1229901006cM0373170006pMX: Distant metastasis cannot be assessed (breast)1229901006cM0373171005pM1: Distant metastasis (breast)1229916009pM1373172003pT1: Tumor 2 cm or less in greatest dimension (breast)1228957006pT1373173008pTX: Primary tumor cannot be assessed (breast)1228950008pTX373175001pTis: Carcinoma in situ (breast)1228953005pTis373176000pTis: Ductal carcinoma in situ (breast)1228954004pTis(DCIS)373177009pTis: Lobular carcinoma in situ (breast)1228953005pTis373178004pTis: Paget disease without invasive carcinoma (breast)1228956002pTis(Paget)373179007pT1mic: Microinvasion 0.1 cm or less in greatest dimension (breast)1228958001pT1mi373180005pT1a: Tumor more than 0.1 cm but not more than 0.5 cm in greatest dimension (breast)1228959009pT1a373182002pT2: Tumor more than 2 cm but not more than 5 cm in greatest dimension (breast)1229852009pT2373183007pT1c: Tumor more than 1 cm but not more than 2 cm in greatest dimension (breast)1229846008pT1c373184001pT3: Tumor more than 5 cm in greatest dimension (breast)1229859000pT3373185000pT4: Tumor of any size with direct extension to chest wall or skin (breast)1229864001pT4373186004pT4a: Tumor of any size with extension to chest wall, not including pectoralis muscle (breast)1229865000pT4a373187008pT4b: Tumor of any size with edema (including peau d'orange) or ulceration of the skin of the breast or satellite skin nodules confined to the same breast1229866004pT4b373189006pT4c: Tumor of any size with direct extension to chest wall (not including pectoralis muscle) and edema (including peau d'orange) or ulceration of the skin of the breast or satellite skin nodules confined to the same breast1229867008pT4c373204007pT1b: Tumor more than 0.5 cm but not more than 1 cm in greatest dimension (breast)1228962007pT1b406088001pN0(i-): No regional lymph node metastasis histologically, negative morphologic findings for isolated tumor cells (breast)1229947003pN0406089009pN0(i+): No regional lymph node metastasis histologically, positive morphologic findings for isolated tumor cells, no cluster greater than 0.2 mm (breast)1229949000pN0(i+)406090000pN0(mol-): No regional lymph node metastasis histologically, negative nonmorphologic (molecular) findings for isolated tumor cells (breast)1229947003pN0406091001pN0(mol+): No regional lymph node metastasis histologically, positive nonmorphologic (molecular) findings for isolated tumor cells (breast)1229950000pN0(mol+)86049000Neoplasm, malignant (primary)1240414004Malignant neoplasm91512002Diagnostic procedure on breast392089008Breast procedure93194002Malignant lymphoma of lymph nodes of axilla AND/OR upper limb1255906008Malignant lymphoma of lymph nodes of upper limb93523009Hodgkin's disease of lymph nodes of axilla AND/OR upper limb1255905007Hodgkin disease of lymph nodes of upper limb

Dentistry Ireland Refset: 

10775006Root canal therapy, retreatment of molar, by report1231801002History of revision of root canal treatment of molar tooth10775006Root canal therapy, retreatment of molar, by report1231800001Revision of root canal treatment of molar tooth56289008Root canal therapy, retreatment of bicuspid, by report1231805006History of revision of root canal treatment of premolar tooth56289008Root canal therapy, retreatment of bicuspid, by report1231796007Revision of root canal treatment of premolar tooth58814005Root canal therapy, retreatment, anterior, by report1231799000History of revision of root canal treatment of anterior tooth58814005Root canal therapy, retreatment, anterior, by report1231798008Revision of root canal treatment of anterior tooth

Adult Safeguarding Refset: 

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, some no Known Issues were identified, and agreed to be resolved in the next editing cycle:

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. 

For the SNOMED CT Managed Service - Ireland Extension Release, the some Issues were Resolved: 

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 2023.

4.4 Changes to the Identifier file format

In line with the proposals documented here:  https://confluence.ihtsdotools.org/mag/snomed-international-proposal-to-change-the-rf2-identifier-file-specification - the Ireland Extension Release will from now on include the following changes to the format of the Identifier files:

• < identifierSchemeId    alternateIdentifier    effectiveTime    active    moduleId    referencedComponentId           ...to
• > alternateIdentifier    effectiveTime    active    moduleId    identifierSchemeId    referencedComponentId

These improvements are introduced in the October 2023 Ireland Extension release, and will be used in all future Ireland Extension releases until further notice.