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 July 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 July 2023 International release.

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 during the release.

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 July 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.

1.5. Important Information

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 July 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.

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 release the next stage has been implemented for subsequent releases including July 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. 

2.2.1. Dental "Fit X" 

Dental procedure concepts in the format "Fit X” e.g. 234856007 |Fit removable orthodontic retainer (procedure)| have been inactivated with reason “ambiguous". This change has been agreed with the Dentistry Clinical Reference Group and approximately 50 concepts were included in this update.

This work is part of Content Tracker IHTSDO-122

2.3. Body Structure 

2.3.1. Review of 410784007|Structure of tendon sheath within lower limb (body structure)

The hierarchical relationships for 410784007|Structure of tendon sheath within lower limb (body structure)| and descendants have been updated to align with the model for tendon here.

2.3.2. Update for 29143008 |Structure of alveolar process (body structure)

After discussion with the Dentistry Clinical Reference Group, 29143008 |Structure of alveolar process (body structure)| has had one of its parents changed from 28035005 |Tooth, gum, and/or supporting structure (body structure)| to 54308001 |Structure of gum and supporting structure of tooth (body structure)|.

2.3.3. 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. Update hierarchy 398114001|Ehlers-Danlos syndrome (disorder)

A review of 398114001|Ehlers-Danlos syndrome (disorder) and subtypes has been undertaken to remove overlap, duplication and outdated concepts.

2.5. Collaboration/Harmonization Agreements

2.5.1. Convergent Medical Terminology (CMT)

80 new concepts have been added for the July 2023 release. These are predominately oncology disorder concepts.

2.5.2. 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.

2.5.3. 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 

2.5.4. 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)|.

Further information about the changes is available here. 

2.5.5. Gravity Project

Work is ongoing for this content area.

2.6. Internal Quality Improvement

2.6.1. Machine Readable Concept Model (MRCM) Changes

There have been no changes made to the MRCM for the July 2023 international release. Changes that are in progress can be viewed via the MRCM Daily Build Browser

Please see early visibility for future planned changes to MRCM.

2.7. SNOMED CT derived products

2.7.1. 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 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 July 2023

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

• 334 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

2.7.2. 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. Configuration file in the RF2 package, containing Release Metadata 

A configuration file ("release_package_information.json") is now included in the International Edition, containing metadata about the Release package itself, including:

• effectiveTime
  

• previouslyPublishedPackage

• languageRefset(s)

• licenceStatement

The metadata will be continually refined going forward, so if you have any ideas about useful information to include please send them to release@snomed.org, along with a business case explaining how the information would benefit stakeholders.  Please be aware that use cases will then be assessed by SNOMED International, and new metadata will only be added for strong business cases.  

3.3.3. 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