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 November 2022 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 November 2022 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 November 2022 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 November 2022 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 November 2022. 

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 Disjunctive Concepts in 363346000 |Malignant neoplastic disease (disorder)| Hierarchy

Descendants of 363346000 |Malignant neoplastic disease (disorder)| that include a disjunctive "and/or" in the FSN have been inactivated.

• 15 concepts containing " extranodal AND/OR solid organ site" e.g., Malignant lymphoma of extranodal AND/OR solid organ site (disorder) have been inactivated with a historical association target to the parent concept (or the relevant concept without 'extranodal AND/OR solid organ site'). The origin of these concepts has been traced to ICD-9 grouper codes.
• 14 malignant neoplastic concepts containing 'head, face AND/OR neck' Example: 93533001 |Hodgkin's granuloma of lymph nodes of head, face AND/OR neck (disorder)| have been inactivated and 3 new replacement concepts created for the 3 sites of head, neck and head and neck. Also, the inactivation of 1 benign concept: 109920008 |Benign neoplasm of peripheral nerve of head, face AND/OR neck (disorder) | and creation of 3 new replacements.
• 15 concepts containing 'lymph nodes of axilla AND/OR upper limb' e.g., 93185008 |Malignant histiocytosis of lymph nodes of axilla AND/OR upper limb (disorder)| have been inactivated and new replacement concepts created for 'lymph nodes of upper limb'. Where these concepts had primitive subtypes for 'lymph nodes of axilla and upper limb' (11 concepts) these concepts were also inactivated.
• 12 malignant neoplastic concepts containing 'lymph nodes of inguinal region AND/OR lower limb' Example: 93516008 |Hodgkin's disease, nodular sclerosis of lymph nodes of inguinal region AND/OR lower limb (disorder)| have been inactivated and new replacement concepts created for 'lymph nodes of lower limb'. This work includes inactivation of their primitive subtypes for 'lymph nodes of inguinal region and lower limb' (12 concepts). Also, inactivation of 188044004 |Malignant melanoma of scalp and /or neck (disorder)| and 3 new replacements created.

2.2.2. Primary and Metastatic Project - Inactivation of Neoplastic Morphologies Stated as 'Primary' in the FSN

86049000 |Malignant neoplasm, primary (morphologic abnormality)| and 367651003 |Malignant neoplasm of primary, secondary, or uncertain origin (morphologic abnormality)| have been inactivated. The reason for inactivation is Nonconformance to Editorial Policy, and the replacement is new concept 1240414004 |Malignant neoplasm (morphologic abnormality)|.

Similarly, other neoplastic morphologies with 'primary' in their FSN have been inactivated:

• 1187469002 |Squamous cell carcinoma of primary, secondary, or uncertain origin (morphologic abnormality)|
• 450594004 |Primary malignant adenomatous neoplasm (morphologic abnormality)|
• 252988009 |Malignant squamous tumor, primary (morphologic abnormality)|
• 400156001 |Malignant blood vessel neoplasm, primary (morphologic abnormality)|
• 719952009 |Primary sarcoma (morphologic abnormality)|
• 734095001 |Primary solid type intraosseous squamous cell carcinoma (morphologic abnormality)|
• 733913003 |Primary intraosseous squamous cell carcinoma derived from keratocystic odontogenic neoplasm (morphologic abnormality)|
• 278411006 |Primary intra-osseous carcinoma (morphologic abnormality)|
• 733912008 |Primary intraosseous squamous cell carcinoma derived from odontogenic cyst (morphologic abnormality)|
• 720346009 |Primary seminoma (morphologic abnormality)|
• 133850008 |Primary synovial chondromatosis (morphologic abnormality)|

These inactivations impact around 2,400 concepts in the disorder hierarchy, and approximately 1200 observable entity concepts (2,000 disorders impacted following inactivation of 86049000 |Malignant neoplasm, primary (morphologic abnormality)|) and all primary malignancy disorder concepts have been restructured with an attribute-value relationship i.e. 370135005 |Pathological process (attribute)| and 704321009 |Characterizes (attribute)| in the Observable entity hierarchy, with a target value of 1234914003 |Malignant proliferation of primary neoplasm (qualifier value)| .

Note: As this large project develops, certain inconsistencies carried forward from current content may still be in evidence, including certain adenocarcinoma disorders that are modeled with 1186968006 |Malignant adenomatous neoplasm (morphologic abnormality)| in order to ensure that there is no change to the current hierarchical subsumption and the assignment of subtypes by the classifier. As the project develops these inconsistencies will be addressed, and in particular the members of the pathology group give their expert input to update the neoplastic morphologies in SNOMED CT and align with ICD-O-3.2.

2.2.3. Content Update Parasitic Process

Around 200 concepts were updated by adding a relationship with 370135005 |Pathological process (attribute)| and value 442614005 |Parasitic process (qualifier value) into the role group with the 246075003 |Causative agent (attribute)|. Most of the content updated were descendants of 17322007 |Disease caused by parasite (disorder)|; a few clinical findings concepts were updated as part of this process.

2.3. Body Structure 

2.3.1. New Concepts for Dural Sinus

New concepts for marginal and petrosquamous dural sinuses have been added - synonyms of the inferior and superior anastomotic veins have been corrected.

2.3.2. Changes to Organization of Veins

• Corrections and improvements have been made to the organization of veins of intercostals; hemorrhoidal plexus; bronchial and lung.
• The concept of ‘venulae rectae‘ has been inactivated as being equivalent to ‘venulae rectae of medulla of kidney’.
• The relationships of veins related to the vertebral column have been rationalized - the concept Vertebral venous system structure (body structure) has been inactivated as it is potentially ambiguous referring to Batson plexus, which actually relates to the Structure of external vertebral venous plexus (body structure) - Structure of suboccipital venous plexus (body structure) has also been relocated as a venous network of the head.

2.3.3. Description Change Left Main Coronary Artery

The descriptions have been updated for the "Left main coronary artery" and new segmental parts, ostium, mid- segment, and distal segment have been added.

2.3.4. Change for Diploic Vein

The anomalous synonym 'diploic vein' on the concept 153824004|Structure of vein of skull (body structure)| has been inactivated. A new concept 'Structure of diploic vein' has been added to subsume the more specific cranial bone diploic structures.

2.3.5. 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. Congenital and Acquired Atrioventricular Septal Defects

New concepts for congenital and acquired atrioventricular septal defects (AVSD) have been added.

Subconcepts have been remodeled following the pattern for congenital diseases.  

The "associated with" relationship in the concept model has been inactivated and represented as a co-occurrent of AVSD.

2.4.2. Update to 128105004|von Willebrand disorder (disorder)| and Descendants

Descendants of 128105004|von Willebrand disorder (disorder)| have been reviewed and remodeled.

Duplicate concepts that were descendants of 234446004|Congenital von Willebrand's disease (disorder)| have been inactivated.

2.5. Qualifier Value

2.6. Substance

2.7. Pharmaceutical/Biological Product

2.8. Physical Object

2.8.1. Inactivation of 705404007 |Walker/Walking frame (physical object)| and 705406009 |Walker (physical object)|

Concepts 705404007 |Walker/Walking frame (physical object)| and 705406009 |Walker (physical object)| have been inactivated as ambiguous as the term 'walker' is being used to represent both walking frames and wheeled walkers (rollators).

A new concept 1255320005 |Wheeled walker (physical object)| has been created with a clear definition added to both that and 266731002 |Walking frame (physical object)|.

Concepts that were previously subtypes of 705406009 |Walker (physical object)| have been inactivated with an inactivation replacement value to a new explicit wheeled version of those concepts and where applicable a pre-existing subtype of 266731002 |Walking frame (physical object)| in addition.

2.9. Collaboration/Harmonization Agreements

2.9.1. Convergent Medical Terminology (CMT)

71 new CMT concepts with a focus on the injury domain have been added for the November 2022 release.

2.9.2. 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.

2.9.3. ICD-11 Update

The November 2022 release has seen continued addition of content for this project.

2.9.4. 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 

2.9.5. Social Determinants of Health - Gravity Project

25 new concepts have been added for the November 2022 release with a focus on referral and education procedures.

2.9.6. International League Against Epilepsy (ILAE)

Work is ongoing to content in the hierarchy << 313307000 |Epileptic seizure (finding)| for this project, the next scheduled publication of these changes will be in the February 2023 release.

Further information about the changes is available here. 

2.10. Internal Quality Improvement

2.10.1. Machine Readable Concept Model (MRCM) Changes

There have been no changes for the November 2022 release.

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

Please see early visibility notification for details of future changes to the MRCM.

2.11. SNOMED CT derived products

2.11.1. 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)|.

2.11.2. 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 November 2022

The map provided for the November 2022 release has been updated, and now represents a complete map from SNOMED CT International release to ICD-10 2016 version.

• 465 newly authored concepts have been added and mapped.

• The SNOMED to ICD-O (morphology) map has 9 additional concepts added as a result of the ICD-O 3.2 review or added due to CRS requests. Of the 9 newly authored concepts 2 can be mapped however 7 are unclassifiable in ICD-O version 3.1. The intention is to map them in version 3.2 if a target map exists.

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

2.11.3. 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

2.11.4. 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 2022 Monthly International Edition releases

Please see the following page for details of all upcoming changes planned for 2022: 

•  https://confluence.ihtsdotools.org/display/RMT/2022+Early+Visibility+Release+Notice+-+Planned+changes+to+upcoming+SNOMED+International+Release+packages