Introduction

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.

Purpose

This document provides a summarized description of the content changes included in the June 2023 release of SNOMED Clinical Terms^® (SCT) International Release.

It also includes technical 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 June 2023 International release.

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.

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 June 2023 International release.

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

Content Development Activity

Summary

Continuous quality improvement and enhancement of existing content is an ongoing process undertaken by SNOMED International in preparation for every release. The June 2023 International Release 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.

Quality Initiative

The Quality Initiative (QI) project is the implementation of the Quality Strategy. After a successful pilot project for the July 2018 release the next stage has been implemented for subsequent releases including June 2023. 

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. 

Update Descriptions for Sperm/Spermatozoa

Update of approximately 112 concepts which had the term ‘sperm’ in the FSN, this has been expanded to spermatozoa.

Body Structure 

 Revision of Ligaments

Revision of 26 ligaments in the shoulder region, elbow joint, and upper limb, which improved the classification results of 60 concepts in the disorder hierarchy.

The key issues that have been addressed are:

1. Improved relationships by distinguishing the ligaments of a joint from the ligaments of a body region. The "ligament of upper limb" represents ligaments within the upper limb region. It includes ligaments between bones, and ligaments of joints within the upper limb.

2. New concepts for ligament of the shoulder region have been added to support modeling disorders, which subsume ligaments of the shoulder joint, acromioclavicular joint, sternoclavicular joint etc.

3. Resolved incorrect hierarchical arrangement of the annular ligament of the radius and its ancestors.  

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.

Qualifier Value

Inactivation of Concepts for Whole Body Structure

Six qualifier value concepts for whole body structures (qualifier value) have been inactivated and replaced by the concepts in the anatomy hierarchy.

New Content - American Joint Committee on Cancer (AJCC)

New subtypes added to 1222584008 |American Joint Committee on Cancer allowable value (qualifier value)|.

Based on requests from several member countries through the Content Managers Advisory Group (CMAG), AJCC approved the addition to SNOMED CT of new cancer staging content as part of a joint collaborative process agreed between both organizations.

Following an AJCC review of the requested new content, 248 new concepts have been added to SNOMED CT.

 Clinical Finding

Updates for Range of Ankle Movement

Following a member query relating to range of ankle flexion, outdated content has been identified in this area along with confusion over synonymy.

Content has been updated to reflect current practice, for example:

• 299432004 |No passive range of ankle flexion (finding)| had a synonym of No passive range of ankle dorsiflexion.
• 299443007 |No passive range of ankle extension (finding)| had a synonym of No passive range of ankle plantarflexion.

A review to verify the synonymy of this historical content was undertaken. In discussion with domain experts for this area, 28 concepts have been inactivated and replaced with concepts reflecting current practice, for example:

• 1285256004 |No passive range of ankle dorsiflexion (finding)|
• 1285275009 |No passive range of ankle plantar flexion (finding)|

Pressure Injury

Inactivation of synonym 'Pressure ulcer' on Pressure Injury concepts Stage I and unstaged has been undertaken to align with editorial guidance and National Pressure Injury Advisory Panel staging guidelines.

Tumor Staging Finding

385379008 |Tumor-node-metastasis (TNM) tumor staging finding (finding)| and its 13 subtypes have been inactivated.

Following agreement with the American Joint Committee on Cancer (AJCC), and based on the current TNM classification, and in collaboration with the experts at the AJCC the relevant information can now be found in the hierarchy of 1222584008 |American Joint Committee on Cancer allowable value (qualifier value)|.

Procedure

Endoscopy of Multiple Body Sites

A number of endoscopy procedures have been remodeled. Naming individual scopes for procedures that involve multiple body sites leads to inconsistent inferences. Therefore 37270008|Endoscope, device (physical object)| has been implemented in the model as the value for 424226004|Using device (attribute)| to improve subsumption. For example, this change has been implemented for 76009000|Esophagogastroduodenoscopy (procedure)|.

Update for Administration of substance via X specific route (procedure)

Instances of “Administration of substance via X specific route (procedure)” have been replaced with concepts of type “Administration via X specific route (procedure)”.

This change is part of the Substance-Drug project and will allow for the unambiguous subsumption of the subtypes, if and once instances of 363701004 |Direct substance (attribute)|are modeled with subtypes of 373873005 |Pharmaceutical / biologic product (product)|. The only remaining concept of this type is the parent concept 433590000 - Administration of substance via specific route (procedure). The change for this concept is is pending required MRCM changes, and will be applied once the required MRCM change is complete and in one of the future releases.

Collaboration/Harmonization Agreements

Convergent Medical Terminology (CMT)

351 new clinical finding concepts have been added across several domains including gastrointestinal, neurological, gynaecological, otological, cardiovascular, obstetrics and injury.

Orphanet

Working in collaboration with Orphanet (http://www.orpha.net/consor/cgi-bin/index.php), content development is ongoing for rare disease concepts in SNOMED CT. Content in scope for this project is published in the annual update of the SNOMED CT to Orphanet Maps.

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

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 

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)|.

Further information about the changes is available here. 

Gravity Project

Work is ongoing for this content area.

Internal Quality Improvement

Machine Readable Concept Model (MRCM) Changes

The domain and proximal primitive refinement have been updated to the MRCM of situations of findings and procedures. The existing exclusion constraints for domains are removed. The "associated finding" and "associated procedure" have been added as mandate requirements, and the contexts have been removed. The details can be found in the JIRA tickets:

Update cardinality domain constraints for Procedure with explicit context

Update cardinality domain constraints for Finding with explicit context

Changes that are in progress can be viewed via the MRCM Daily Build Browser

Please see early visibility for future changes to MRCM.

SNOMED CT derived products

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 release 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 |ICD-10 complex map reference set (foundation metadata concept)|.

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

2.10.2. 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 June 2023

The map provided for the June 2023 release has been updated, and now represents a complete map from SNOMED CT International release to ICD-10 2016 version.

• 732 newly authored concepts have been added and mapped.

• The SNOMED to ICD-O (morphology) map has 2 additional concepts 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

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.

Technical notes

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:

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:

Technical updates

RF2 package format

For future reference, the RF2 package convention dictates that it contains all relevant files, regardless of whether or not there is content to be included in each particular release.  Therefore, the package contains a mixture of files which contain both header rows and content data, and also files that are intentionally left blank (including only a header record).  The reason that these files are not removed from the package is to draw a clear distinction between files that:

• have been deprecated (and therefore removed from the package completely), due to the content no longer being relevant to RF2 in this or future releases, and 

• happen to contain no data in this particular release (and are therefore included in the package but left blank, with only a header record), but are still relevant to RF2, and could therefore potentially contain data in future releases.

This allows users to easily distinguish between files that have purposefully been removed or not, as otherwise if files in option 2 above were left out of the package it could be interpreted as an error, rather than an intentional lack of content in that release.

Configuration file in the RF2 package, containing Release Metadata 

A new file has been included since the July 2020 International Edition, containing metadata about the Release package itself.  This has been created in conjunction with feedback from the community, and as such initially contains the following fields:

• effectiveTime
  

• previouslyPublishedPackage

• languageRefset(s)

• licenceStatement

The file is in .JSON format, to ensure that it is both machine-readable and human-readable, and is named "release_package_information.json".

The metadata will be extended and refined going forward, in order to ensure that it contains the most useful information possible. If you have any ideas about any other useful information to include, please send them to info@snomed.org, along with a business case explaining how the information would benefit stakeholders.  Please be aware that this use case will then be assessed by SNOMED International, and the new metadata will only be included in the configuration file if the business case is strong enough.  

Early visibility of impending changes in the upcoming 2023 Monthly International Edition releases

Please see the early visibility page below for details of forthcoming changes:

• https://confluence.ihtsdotools.org/display/RMT/2023+Early+Visibility+Release+Notifications

Plan to move the International Monthly release date to the first of each month

After consultation with the community, SNOMED International are planning to change the dates of the International Edition from the end of each month, to the first of each month.  This will mean that in addition to all of the other months, the “January” release would move from 31st January to the 1st January, and the “July” release would move from 31st July to 1st July each year.  Further details of this proposal can be found in the Q&A blog post below, however if you have any concerns please provide feedback to release@snomed.org as soon as possible. 

• https://www.snomed.org/news/blog%3A-the-snomed-ct-international-edition-to-be-published-on-first-day-of-each-month