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 January 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 January 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 January 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.

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 January 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 January 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. Inactivation of Concepts that Specify Delivery Status of Mother 

As detailed in this briefing note approximately 250 concepts that specify the delivery status of the mother within the FSN have been inactivated, for example:

• 198905007 |Placenta previa with hemorrhage - delivered (disorder)|
• 198906008 |Placenta previa with hemorrhage - not delivered (disorder)|

The above concepts are classification derived and were used to record whether the baby was or was not delivered during that inpatient stay for the care of the mother who has placenta previa with a hemorrhage.

Concepts of this type are derived from ICD-9. Both ICD-10 and ICD-11 have ceased to conflate the condition for admission with the delivery status at discharge and therefore mapping to these classifications is not impacted by the inactivation of this SNOMED CT content.

2.2.2. Inactivation of Descendants of 229984009 |Arm position finding (finding)|

Concepts related to arm position which were descendants of 229984009 |Arm position finding (finding)| have been inactivated after diligent investigation could not determine the meaning of the concepts.

2.2.3. Review of 444107005|Exposure to communicable disease (event)|

The concept 444107005|Exposure to communicable disease (event)|has been reviewed and moved to the subhierarchy of navigational concepts because of a lack of agreement on the definition. The concept FSN is now 444107005 |Exposure to communicable disease (navigational concept)|.

Classification results have been improved after the remodel of related 40 concepts. Many lists of communicable diseases are developed by individual public health agencies, it is recommended that diseases of public health significance in specific countries are arranged by relevance in national extensions.

2.3. Body Structure 

2.3.1. Remodel of Tendons of Wrist and Hand

Work has been undertaken to update the relationship between segments of tendons within certain regions e.g. hand, finger and the entire tendon which may transit one or a number of regions e.g. flexor pollicis longus. Where necessary the allocation of the exact tendon for the modeling of findings or procedures has been updated improving the logical classification.

2.3.2. Remodel 79561009 |Structure of right side of heart (body structure)|

79561009 |Structure of right side of heart (body structure)| has been remodeled to a more general class and equivalent to the status/position of left side of heart - the impact of this change is minimal but it improves the classification of the few concepts which depend on the anatomy.

2.3.3. Update Anal Canal

The relationships of a small number of concepts related to the anal canal, particularly the venous supply, have been updated.

2.3.4. New Concepts for Entire

The previously omitted 'entire' versions for a small subset of arterial concepts have been added. 

2.3.5. Updates for Lateralizable Structures

Update for lateralizable structures such as 299717005 |Structure of carotid and/or cerebral and/or subclavian artery (body structure)|, 51416005 |Structure of central branch of circle of Willis (body structure)| and their subconcepts. A new GCI axiom is added to the "lateral half of body" to capture potential missing lateralizable subtypes.

2.3.6. 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. New Metastatic Morphologic Abnormality Concepts and Disorders

Metastatic disorders are being defined by their specific metastatic neoplastic morphologic abnormality concepts, and new metastatic morphologies have been added and will continue to be added as needed.

In cooperation with the Netherlands extension of SNOMED CT, SNOMED International have begun promoting metastatic morphology concepts to the International release to be used to model new and existing metastatic disorder concepts.

2.5. Procedure

2.5.1. Update for 399248000 |Procedure related to anesthesia and sedation (procedure)|

745638006 |Injection of anesthetic agent (procedure)| and its 283 subtypes have been remodeled to add a supertype of 399097000 |Administration of anesthesia (procedure)|.

2.6. Organism

2.6.1. Inactivation of 415360003 |Severe acute respiratory syndrome-related coronavirus (organism)|

To resolve ambiguity for 415360003 |Severe acute respiratory syndrome-related coronavirus (organism)|, this concept was inactivated as ambiguous. New concepts have been created to represent the associated strain and species. 840533007 |Severe acute respiratory syndrome coronavirus 2 (organism)| is now a sibling of the “Severe acute respiratory syndrome (SARS) coronavirus” strain and a subtype of the “Severe acute respiratory syndrome-related coronavirus” species.

Children of 415360003 |Severe acute respiratory syndrome-related coronavirus (organism)|, which represent SARS strain subtypes have been inactivated using "Outdated component" as the inactivation reason with a "Replaced by" association to the concept representing “Severe acute respiratory syndrome (SARS) coronavirus".

2.7. Qualifier Value

2.7.1. Inactivation of 260299005 |Number (qualifier value)| and Descendants

Following the deployment of the concrete domain functionality in SNOMED CT, concepts in the 260299005 |Number (qualifier value)| hierarchy are no longer necessary and these concepts have been inactivated to align with the briefing note published in 2022.  Concepts have been inactivated with reason “Non-conformance to editorial policy” and no historical relationship or replacement concept provided.

Exceptions:

• 118586006 |Ratio (property) (qualifier value)| and descendants have been relocated to 118598001 |Property (qualifier value)| hierarchy
• 272070003 |Ordinal number (qualifier value)| and descendants have been relocated to 362981000 |Qualifier value (qualifier value)|

2.7.2. Update for Clinical Course Recurrent

255227004 |Recurrent (qualifier value)|is no longer a subtype of 90734009 |Chronic (qualifier value)| as conditions end and then recur; chronic conditions do not end. The Recurrent course can now be found as a direct subtype of 288524001 |Courses (qualifier value)|.

2.8. Collaboration/Harmonization Agreements

2.8.1. Convergent Medical Terminology (CMT)

The January 2023 release has seen a continuation of work for this project.

2.8.2. 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.

2.8.3. ICD-11 Update

The January 2023 release has seen continued addition of content for this project.

2.8.4. 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 

2.8.5. 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. 

2.9. Internal Quality Improvement

2.9.1. Machine Readable Concept Model (MRCM) Changes

There have been no changes for the January 2023 release.

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

Please see early visibility notification for change to MRCM.

2.10. SNOMED CT derived products

2.10.1. 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)|.

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 forJanuary 2023

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

• 395 newly authored concepts have been added and mapped.

• The SNOMED to ICD-O (morphology) map has one 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

2.10.3. Technical Guide Exemplars

The Technical Guide Exemplars document has now been moved from the International Edition release package to a Confluence page.  This page can be found as part of the ICD-10 Mapping Technical Guide (see Appendix B), which is hosted here:  http://snomed.org/icd10map

2.10.4. 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

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.  

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

Please see https://confluence.ihtsdotools.org/display/RMT/2023+Early+Visibility+Release+Notifications for details of forthcoming changes.