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 September 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 September 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 September 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 September 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. Updates for Concept Inactivation Values

Please see editorial guidance for changes to concept inactivation values here.

2.3. 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 September 2022. 

Quality improvement tasks were 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 was carried out to accurately reflect current clinical knowledge and ensure the semantic reliability of descriptions associated with a concept.

2.3.1. Lesion

Concepts with Associated morphology values using 52988006 |Lesion (morphologic abnormality)| and its subtypes have been inconsistently modeled as either Disorders or Clinical findings. As part of the Quality Improvement project for SNOMED CT, an evaluation of these concepts has found that the majority of these concepts have been modeled as disorders.

To improve modeling consistency and taxonomic relationships, many “Lesion” concepts and subtypes originally modeled as Clinical findings have been remodeled as disorders.

Exceptions to this general remodeling include concepts using the ASSOCIATED MORPHOLOGY = Mass and ASSOCIATED MORPHOLOGY = 400157005 |Scratch (morphologic abnormality)| and those using a lesion morphology that are no longer considered diseases (e.g. Fibrocystic changes of breast).

2.3.2. Primary and Metastatic Project - Inactivation of Certain Metastatic Disorders

7 concepts termed ‘Malignant tumor involving an organ by separate metastasis from X’ and 20 concepts termed ‘Metastasis from malignant neoplasm of X’ have been inactivated.

Metastasis ‘involving an organ’ and metastasis concepts that are unspecified as to site of the metastatic neoplasm are not clinically useful as in most cases there will already be a record of the site of the primary malignant tumor and the actual site of the metastasis will also be recorded as a separate concept.

Going forward, metastatic malignant neoplasm ‘to X site’ and ‘from X site’ will not be precoordinated in one concept but recorded separately as 2 concepts.

2.4. Body Structure 

2.4.1. Inactivation of 371415005 |Abnormal retraction (morphologic abnormality)

The morphologic abnormality concept 371415005 |Abnormal retraction (morphologic abnormality)| has been inactivated and replaced with 1237295003 |Retracted structure (morphologic abnormality)|.

This has led to changes to the descriptions and/or modelling of approximately 50 concepts.

2.4.2. 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.

2.5. Clinical Finding

2.5.1. Update for Subtypes of 13197004 |Uses contraception (finding)| 

Improvement has been made to the descriptions for subtypes of 13197004 |Uses contraception (finding)| the changes have been made to align with the logical definition.

2.5.2. Remodel of 410812005|Dupuytren's disease (disorder)| Hierarchy

Content relating to Dupuytren disease has been remodeled.

The following concepts have been inactivated for the September 2022 Release:

410812005 |Dupuytren's disease (disorder)| 
203052004 |Dupuytren's disease of palm and finger (disorder)| 
203046000 |Dupuytren's disease of palm, nodules with no contracture (disorder)|
203047009 |Dupuytren's disease of palm, with contracture (disorder)|
203050007 |Dupuytren's disease of finger(s), nodules with no contracture (disorder)|
203053009 |Dupuytren's disease of palm and finger(s), nodules with no contracture (disorder)|
203051006 |Dupuytren's disease of finger, with contracture (disorder)|
203054003 |Dupuytren's disease of palm and finger, with contracture (disorder)|
16216861000119107 |Dupuytren's contracture (morphologic abnormality)|

2.6. Procedure

2.6.1. Inactivation and Replacement of 76981001|Discogram (procedure)| and Subtypes

76981001|Discogram (procedure)| and subtypes have been inactivated and replaced with concepts that explicitly state the use of contrast and injection into the intervertebral disc.  

The replacement concepts follow the pattern 'Discography with injection of contrast into intervertebral disc'.

2.7. Qualifier Value

2.8. Substance

2.8.1. Inactivation of 360215002 |Pharmaceutical excipient (substance)| Hierarchy

The 360215002 |Pharmaceutical excipient (substance)| hierarchy has been inactivated with descendant grouper concepts (e.g. 418403001 |Drug preservative (substance)|, 412307009 |Drug vehicle (substance)|) being inactivated as duplicates of existing or new concepts in the 43747001 |Drug excipient (product)| hierarchy.

Concepts representing discrete substances remain in the Substance hierarchy. One concept, 438784000 |Adverse reaction caused by pharmaceutical excipient (disorder)|, was remodeled using the corresponding product concept, with classification results consistent with the pattern for vaccine products.

2.9. Pharmaceutical/Biological Product

2.10. Physical Object

2.11. Collaboration/Harmonization Agreements

2.11.1. Convergent Medical Terminology (CMT)

61 new concepts have been added for the September 2022 release, predominantly relating to skin disorders, respiratory disorders and injuries.

2.11.2. Orphanet

Working in collaboration with Orphanet (http://www.orpha.net/consor/cgi-bin/index.php), creation of new concepts for the original set of prioritized rare diseases has been completed. All of the concepts added for the Orphanet project have been mapped to ICD-10.

The Production release of the SNOMED CT to Orphanet Simple Map was published in October 2021. Work is now underway to add further content to the SNOMED CT to Orphanet Simple Map for future releases starting with the next Production release in October 2022.

2.11.3. ICD-11 Update

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

2.11.4. Cancer Synoptic Reporting

Around 30 concepts representing cancer synoptic reporting content have been added to the September 2022 International release.

Included were observable entity concepts and supporting concepts for representing tumor budding, tumor deposits, dysplasia, and immunohistochemistry testing for neoplasm of breast.

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 

2.12. Internal Quality Improvement

2.12.1. Machine Readable Concept Model (MRCM) Changes

One change has been made for the September 2022 release:

• Extend the range 370135005 |Pathological process (attribute)| to include < < 1495041000004108 |Proliferation of neoplasm (qualifier value)|

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

2.13. SNOMED CT derived products

2.13.1. 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)|.

2.13.2. 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 September 2022

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

• 297 newly authored concepts have been added and mapped.

• The SNOMED to ICD-O (morphology) map has no 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

2.13.3. 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

2.13.4. 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. New Association References

In order to support the Content changes above in section 2.3, the following Association Reference set members have been added to the International Edition from the April 2022 release onwards:

• 1186921001|POSSIBLY REPLACED BY association reference set
  
• 1186924009|PARTIALLY EQUIVALENT TO association reference set

3.3.3. 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