1. Introduction

1.1. Background

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.

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.

1.2. Purpose

This document provides a summarized description of the content changes included in the October 2024 release of SNOMED Clinical Terms^® (SCT) International Edition.

It also includes notes detailing the known content or technical issues where the root cause is understood, the fix has been discussed and agreed to, but has yet to be implemented.

The SNOMED International release notes are available alongside the October 2024 International Edition.

1.3. 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.

1.4. Audience

The audience includes National Release Centers, WHO-FIC release centers, vendors of electronic health records, terminology developers and managers who wish to have an understanding of changes that have been incorporated into the October 2024 International Edition.

Please note, you may have to register for a Confluence user account in order to access the links included in these release notes.

2. Content Development Activity

2.1. Summary

Continuous quality improvement and enhancement of existing content is an ongoing process undertaken by SNOMED International in preparation for every release. The October 2024 International Edition has seen a continuation of the work driven by contributions from: Kaiser Permanente i.e. Convergent Medical Terminology (CMT), Global Medical Device Nomenclature Agency (GMDNA), Orphanet and other domain specific collaborations as well as requests received via the Content Request System (CRS). 

Additionally quality improvement activities are advanced via project driven initiatives summarized below.  Additional work items impacting every release are updates to the SNOMED CT derived maps such as ICD-10 and ICD-O; details are included in these release notes.  

Information about editorial decisions may be found in the SNOMED CT Editorial Guide; mapping guidance for ICD-10 can be found here.

2.2. Quality Initiative

The Quality Initiative (QI) project is the implementation of the Quality Strategy. After a successful pilot project for the July 2018 Edition release, the next stage has been implemented for subsequent releases including October 2024. 

Quality improvement tasks are being deployed to improve internal structural consistency and ensure compliance with editorial policy related to the stated modeling of content. Additionally, correction or addition of defining relationships is being carried out to accurately reflect current clinical knowledge and ensure the semantic reliability of descriptions associated with a concept.  

2.2.1. Inactivation of 264274002 |Endoscopic operation (procedure)| 

264274002 |Endoscopic operation (procedure)| has been inactivated and replaced by 363687006 |Endoscopic procedure (procedure)|. Please see the Editorial Guide for further information about endoscopy and endoscopic procedures.

2.2.2. Review Hierarchy 1287742003 |Radiotherapy (procedure)|

Review and remodeling of the 1287742003 |Radiotherapy (procedure)| hierarchy is in progress. The 260686004 |Method (attribute)| value has been normalized to 129445006 |Administration - action (qualifier value)|. 424244007 |Using energy (attribute)| value has been normalized to 125576007 |Ionizing radiation (physical force)|. A number of changes have been made to 424226004 |Using device (attribute)| values to improve classification results.

Number of concepts edited (approx): 104

2.2.3. Review Hierarchy 152198000 |Brachytherapy (procedure)|

152198000 |Brachytherapy (procedure)| hierarchy has been reviewed and remodeled. The main changes relate to the Method (attribute) value, which has been updated to << 129445006 |Administration - action (qualifier value)|; and Using energy (attribute) value has also been updated to 125576007 |Ionizing radiation (physical force)|.

To ensure that brachytherapy procedures performed by implantation, application or insertion of different brachytherapy devices and implants are subsumed by the top level concept 152198000 |Brachytherapy (procedure)|, the concept has been remodeled with GCI.​

Number of concepts edited (approx): 95

2.2.4. Review Hierarchy 399315003|Radionuclide therapy (procedure)|

399315003|Radionuclide therapy (procedure)| has been updated to include two role groups, the first modeling the administration of ionizing energy and the second modeling the administration of radioactive substances.

Number of concepts edited (approx): 62

2.2.5. Inactivation of Complication Disorder Concepts 

The inactivation of concepts that reference “complication” without specifying the nature of the complication is in progress, please see this briefing note for further information.

The primitive “Complication (disorder)” grouper was inactivated in 2022 due to a lack of consistency or definition of what would properly be assigned as a subtype. The concepts in scope for this review are in the process of being inactivated with inactivation reason “Classification derived concept” and replacement by the parent concept.

2.3.  Body Structure 

2.3.1. SEP and Laterality Anatomy Reference Sets

The release file for the lateralizable body structure reference set has been updated and validated.

The release file for the SEP reference set has been updated and validated.

2.4. Clinical Finding

2.4.1. Substance Abuse/Use

There has been a shift from the term "substance abuse" to a more nuanced understanding of substance use disorders in this domain which is reflected in both ICD-11 and DSM-5 indicating a greater emphasis on the spectrum of substance-related problems.  Several members have expressed the need for content updates to incorporate this change and to simplify the translation process.  Consequently, the content associated with 66214007 |Substance abuse (disorder)| has been updated to reflect these changes. 

An example of the content structure and terming for opioid use is shown below:

Specifically, descriptions have been added with “harmful pattern of X substance use” replacing the term “abuse” in the FSN and PT however the “abuse” descriptions have persisted as synonyms to facilitate searching.  In most cases there is no change in meaning, therefore the concepts have not been inactivated.

Approximately 100 existing concepts relating to “abuse” were affected together with the addition of 82 new concepts to represent “episode of harmful use”, “harmful pattern of use” and the higher level “X substance use disorder.

This work has been undertaken with clinical input from members of the Mental and Behavioral Health Clinical Reference Group.

2.4.2. Inactivation of 302081005|Finding of sex of baby (finding)| and Subtypes

302081005|Finding of sex of baby (finding)| and subtypes have been inactivated, 'baby' may mean fetus, neonate, infant.

New observable entity concepts have been added to represent ‘Sex of fetus’ and ‘Sex of neonate’.

The existing observable entity concepts 268476009 Sex of baby (observable entity) and 281053000 Sex of baby at delivery (observable entity) have been inactivated with historical associations to the new observable concepts.

2.4.3. New Concept - Pain of hip joint (finding)

A new concept 1348356003 Pain of hip joint (finding) has been created to describe pain of the hip joint. This is distinguished from its supertype, |Pain of hip region|, which includes the joint but also other sites outside the joint itself but still within the hip region.

2.5. Procedure

2.5.1. Radiographic Imaging

Work is progressing for this content tracker for information please see the informational briefing note here.

As part of this project << 241686001|Dual energy X-ray absorptiometry (procedure)| has been remodeled along with associated finding and situation concepts.

A new imaging action has been added 1345096008 |Dual energy X-ray absorptiometry imaging - action (qualifier value)|

These concepts have been inactivated:

• 241685002 |X-ray photon absorptiometry (procedure)|
• 277458000 |Single energy X-ray photon absorptiometry (procedure)|

The editorial guide will be updated to reflect these changes.

2.5.2. Update Hierarchy 35202002|Scanning or imaging with vascular flow (procedure)|

The 35202002 |Scanning or imaging with vascular flow (procedure)| hierarchy has been updated. The value for the 260686004 |Method (attribute)| has been modified to align with the fully specified name.

Number of concepts edited (approx): 22

2.6. Qualifier Value

2.6.1. Inactivation of Descriptions with Asterisk

Eight concepts containing an asterisk instead of a superscript to represent "power of," e.g. 277288007 |10*9/liter (qualifier value)|, have been inactivated with reason ambiguous. New replacement concepts have been created, e.g. 1348323004 |10^9/liter (qualifier value)|.

The concepts that have been inactivated and replaced were all subtypes of 282409001 |Nominated concentrations (qualifier value)|).

Editorial guidance is available here.

2.7. Collaboration/Harmonization Agreements

2.7.1. Convergent Medical Terminology (CMT)

37 CMT concepts were added for the October 2024 release. The main focus areas were musculoskeletal disorders and 'history of' content.

2.7.2. Orphanet

Working in collaboration with Orphanet efforts are ongoing to update rare disease concepts in SNOMED CT to maintain alignment with Orphanet for the annual update of the SNOMED CT to Orphanet Maps. Work has commenced to annotate content added for the Orphanet project with attribution to Inserm Orphanet.

All of the concepts added for the Orphanet project have been mapped to ICD-10.

2.7.3. Cancer Synoptic Reporting

Cancer synoptic reports are used by many member countries to record pathology examination of cancer specimens including the College of American Pathologists (US and Canada), Royal College of Pathology (UK), Royal College of Pathology Australasia (Australia, New Zealand), PALGA (The Netherlands), Swedish Society of Pathology, and others.

For more information about this project, please see Cancer Synoptic Reporting Clinical Project Group 

2.7.4. International League Against Epilepsy (ILAE)

In line with approved harmonized terminology, this project is working on alignment including restructuring to update the hierarchy  << 313307000 |Epileptic seizure (finding)|.

Changes have been made in the area of focal anatomical epilepsy. This includes the addition of one new concept, the updating of descriptions on current concepts, the addition of definitions and inactivation of outdated concepts. Work in the area is continuing.

Further information about the project is available here

2.7.5. Social Care

65 concepts have been promoted from national extensions and 3 new concepts added to support the Social Care Project work. The main content areas were assessments, counseling procedures, sleep disorders and findings regarding medication use and caring for a child.

2.7.6. Nursing

6 procedure concepts were added to support the nursing domain.

2.8. Internal Quality Improvement

2.8.1. Machine Readable Concept Model (MRCM) Changes

There are no changes for the MRCM in the October 2024 International Edition.

Future changes that are currently in progress can be viewed via the MRCM Daily Build Browser

Please see early visibility for future planned changes to MRCM.

2.8.2. Annotation Reference Set

The addition of content for the Annotations refset was commenced in the July 2024 International Edition release and is ongoing for attribution of text definition to organizations with a collaboration agreement, starting with Inserm Orphanet.

2.9. SNOMED CT derived products

2.9.1. ICD-10 map

The SNOMED CT to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (© World Health Organization 1994) 2016 Version map (SNOMED CT to ICD-10 Map) is included in the SNOMED CT International Edition as a Baseline. The SNOMED CT to ICD-10 Map was created to support the epidemiological, statistical and administrative reporting needs of SNOMED International member countries and WHO Collaborating Centers.

The SNOMED CT to ICD-10 Map is released in Release Format 2 (RF2) only. It is located in the file der2_iisssccRefset_ExtendedMapFull_INT_20200731.txt, which is in the Map folder under Refset, in each of the three RF2 Release Type folders. 

The SNOMED CT to ICD-10 Map is released as Refset 447562003 |SNOMED CT to ICD-10 extended map (foundation metadata concept).

The ICD-10 Mapping Technical Guide (including exemplars) is hosted here https://confluence.ihtsdotools.org/display/DOCICD10

2.9.2. Content Development Activity Summary

The map is a directed set of relationships from SNOMED CT source concepts to ICD-10 target classification codes.  The SNOMED CT source domains for the MAP are limited to subtypes of 404684003 |clinical finding|, 272379006 |event| and 243796009 |situation with explicit context|.  The target classification codes are ICD-10 2016 release. 

Mapped content for October 2024

The map provided for the October 2024 International Edition has been updated, and now represents a complete map from SNOMED CT International Edition to ICD-10 2016 version.

• 256 newly authored concepts have been added and mapped.

• The SNOMED to ICD-O (morphology) map has 1 additional concept added as a result of the ICD-O 3.2 review or added due to CRS requests. 

We would welcome feedback on any issues that users of the map may detect when using the map. Issues should be submitted via mapping@snomed.org

2.9.3. SNOMED CT to OWL conversion and classification

The repository containing the toolkit enabling simple SNOMED CT to OWL conversion and classification can be found here, including documentation on its use: https://github.com/IHTSDO/snomed-owl-toolkit

Please contact SNOMED International at support@snomed.org if you would like to provide any feedback on ways to extend and improve the new toolkit.

3. Technical notes

3.1. 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 time within the new monthly editing cycles, 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 current SNOMED CT International Edition, the following Known Issues were identified, and agreed to be resolved in future editing cycles:

3.2. Resolved Issues

Resolved issues are Known Issues which were not fixed as part of the previous release lifecycle, but which have now been resolved in the latest release.  They can also be issues found during testing of the current release, which were resolved before the final deployment of the Production release.  Finally they can be issues which were reported or found during the testing phase, but which have been closed without any action taken.  

The Resolved Issues for the current SNOMED CT International Edition can be found here:

3.3. Technical updates

3.3.1. RF2 package format

The RF2 package convention dictates that all relevant files are included, regardless of whether or not there is content to be included in each release.  Therefore, the package contains a mixture of files which contain both header rows and content data, and files that (intentionally) include only header records.  The reason that these "empty" files are included in the package is to draw a clear distinction between:

1. ...files that have been deprecated (and therefore removed from the package completely), due to the content no longer being relevant to RF2 in future releases 

2. ...files that happen to contain no data in this particular release (and are therefore included in the package with just a header record), but are still relevant to RF2, and could therefore contain content in future releases.

This allows users to easily distinguish between the two scenarios, as otherwise if files in option 2 were left out of the package it could be interpreted as an error, rather than an intentional lack of content in that release.

3.3.2. Changes to the Annotations Refset format

3.3.3. Changes to the RefsetDescriptor records

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3.3.4.  Proposal to increase the maximum length of Description Types

Please find below the link to the recent announcement on the proposal to increase the limit of characters allowed in Descriptions:

• https://confluence.ihtsdotools.org/pages/viewpage.action?pageId=238158325

A community consultation has been launched to solicit feedback on a proposal to increase the size limits of SNOMED CT concept descriptions to 4096 from the current limit of 255 characters. While this change does not represent a modification of the existing specification, it could be disruptive to implementers who have coded fixed length limits into their systems.  

Please read the full proposal, along with the latest Q&A blog post which details the proposed change, its potential benefits, the feedback process and timelines, and the issues that may need to be considered in such an update:

• https://confluence.ihtsdotools.org/mag/community-consultations/snomed-international-proposal-to-increase-description-length-limit
• https://www.snomed.org/news/blog%3A-snomed-international-seeks-community-feedback-on-proposed-description-character-limit-increase

As always, SNOMED International greatly appreciates any thoughts or opinions that you would like to raise.  If you would like to provide any feedback, please do so as soon as possible, at the very latest before the deadline on Dec 31, 2024.

3.3.5. Early visibility of impending changes in the upcoming 2024 Monthly International Edition releases

Please see the early visibility Confluence page for details of forthcoming changes.