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 July 2020 release of SNOMED Clinical Terms^® (SCT) International Release.

It also includes technical notes detailing the known issues which have been identified and agreed to be released. These are content or technical issues where the root cause is understood, and the fix has been discussed and agreed, but has yet to be implemented.

The SNOMED International Release Notes are available alongside the July 2020 International Edition 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 July 2020 International Edition release.

Content Development Activity

Summary

Continuous quality improvement and enhancement of existing content is an ongoing process by SNOMED International for every release. The July 2020 International Release has seen a continuation of the work driven by contributions from: Kaiser Permanente 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 in progress for new and enhanced content through project driven initiatives which are also summarized below.  Also included as work items for every release are various updates to SNOMED CT derived maps such as ICD-10 and ICD-O and details are also 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 at this link https://confluence.ihtsdotools.org/display/DOCICD10

Content Quality Improvement

Body structure 

New body structure concepts: 306

Completion of the revision of hierarchical relationships provides stable anatomy content and improves the quality of classification results in other hierarchies.

The plan is to implement the new anatomy concept model over forthcoming releases. There are approximately 35,000 anatomy concepts to be modeled by different types of 'part of' relationships. The new model will enable the automatic generation of hierarchies to further improve quality and consistency. The concept model for over 14,000 structure concepts has been tested by batch import of axioms into the authoring platform. In order to gather feedback and evaluate the potential impact on the classification to content in extensions, a demonstration release of the anatomy model changes is planned for January 2021.

Quality Improvement in the Body Structure Hierarchy

Updated modelling for diagnostic imaging procedures related to the changes for abdomen terminology, e.g. CT, MRI, SPECT CT have been implemented.

The notion of ‘abdomen’ in clinical practice can vary between different specialties and circumstances; for example, ‘abdomen’ in natural language can be used to refer to, but is not limited to, the following concepts:

• Abdominopelvic cavity
• Abdominopelvic cavity excluding the true pelvic cavity (Abdomen proper cavity)
• Abdominopelvic cavity and/or content (Intra-abdominopelvic structure)
• Intra-abdominopelvic structure excluding intra-pelvic structure of true pelvis
• Intra-abdominopelvic structure and/or anterior abdominal wall
• Intra-abdominopelvic structure and/or anterior abdominal wall, excluding intra-pelvic structure of true pelvis (Abdomen proper)
• Abdominal segment of trunk
• Abdominal cross-sectional segment of trunk

SNOMED International considers the most commonly used clinical variant referred to as ‘abdomen’ to be 818983003 |Structure of abdominopelvic cavity and/or content of abdominopelvic cavity and/or anterior abdominal wall (body structure)|, which in SNOMED CT is now the only concept using ‘Abdomen’ as a synonym.
Further detail can be found at https://docs.google.com/document/d/1gxkcEYf89eJl0RJG8-S2w4zOdpF8R2sn5SHx7InWxZI/edit?usp=sharing

Revision of the inguinal region, anal structures and vaginal structures have been implemented in order to address some historical sub-optimal classification results.

Updated left coronary arteries following the pattern for branches of blood vessels.

Updated the 17 segments of left cardiac ventricle and eliminated the term 'posterior' from anatomy according to the standard from the American Heart Association.

The missing relationship between jaw and tooth that was reported by the Dentistry Clinical Reference Group has been resolved.

The peripheral arterial anatomy hierarchy has been augmented to improve a number of dependant sections including that of peripheral arterial diseases. The update has addressed over 100 incorrect classification results.

Disorders of mediastinum are modeled by a new anatomy concept |Structure of space and/or soft connective tissue within mediastinal cavity (body structure)|. This has addressed nearly 300 incorrect classifications, such as myocarditis being classified as a type of mediastinitis.

Planned revision of Cell hierarchy in the January 2021 release

The content under 4421005 |Cell structure (cell structure)| will be updated according to the SEP model and description patterns. Descendants of 362837007 |Entire cell (cell)| will be updated to include the word ‘entire’ in all descriptions. The semantic tag ‘(cell)’ will be changed to ‘(cell structure)’. Descriptions for the rest of the concepts will be updated to include the word ‘structure’.
This improvement will reduce the potential misuse of cell concepts.

Please contact info@snomed.org with any inquiries or to submit feedback.

Reference set updates

Updated and validated release file for the lateralizable body structure reference set.
Updated and validated release files for the SEP refsets.

Clinical finding

New concepts added for clinical finding hierarchy: 2073

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 2020. 

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.

Total count of changes for the QI project: 

• Stated: A total of 6835 concepts had changes made to the Stated relationships in the model. 
• Inferred: A total of 10731 concepts affected by inferred changes.

Quality Improvement in the Clinical Finding Hierarchy 

Revision of 129156001|Traumatic dislocation of joint (disorder)|

Traumatic dislocation concepts have been remodeled according to the new representation using DUE TO "traumatic event".  This work was commenced in the January 2020 release and has been completed for the July 2020 release.

Disorder due to birth injury

These concepts have been remodeled according to the new representation using DUE TO 'traumatic event' to be consistent with the new traumatic injury model.

Traumatic brain injury

Traumatic brain injury concepts with specified concrete ranges relating to 'loss of consciousness' have been inactivated due to their limited clinical value and lack of historical usage.

Revision of Spinal Cord Syndrome

A new concept 840721004| Incomplete spinal cord syndrome (disorder) has been created as a grouper parent to the four major subtypes of this syndrome: 

• 282785008 |Anterior cord syndrome (disorder)| 
• 27982003|Brown-Séquard syndrome (disorder)|
• 282786009 |Posterior cord syndrome (disorder)|
• 282787000 |Central cord syndrome (disorder)|

In prior releases these syndromes had been modeled with an ASSOCIATED MORPHOLOGY = 19130008|Traumatic abnormality (morphologic abnormality)|; however, these syndromes may present due to non-traumatic etiologies such as space filling lesions (tumors, etc.) or vascular compromise (occlusions, ruptures, etc.). These syndromes have been remodeled with ASSOCIATED MORPHOLOGY = 52988006|Lesion (morphologic abnormality)|.

Incomplete cord syndromes with a traumatic cause have been remodeled to specifically represent 773760007 |Traumatic event (event)| as the DUE TO value as well as any other relationships to describe associated disorders (e.g. fractures or dislocations).

Malignant neoplasm

The content relating to Primary and secondary malignant neoplasms excluding Malignant tumours of lymphoid, hemopoietic and related tissues have been updated in line with the QI project objectives. This has resulted in an increase in sufficiently defined content and minor movement of previously incorrectly placed content into their appropriate hierarchies. Malignant tumours of lymphoid, hemopoietic and related tissue concepts will be addressed in the next release cycle along with any residual malignant neoplasm content.

Content Tracker Project Updates

Work continues on the following Content Project:

IHTSDO- 393 Diabetes Complications

Other Areas of Quality Improvement in the Clinical Finding Hierarchy

Update 404177007|Angioedema and/or urticaria (disorder)| and descendants

Remodel 404177007|Angioedema and/or urticaria (disorder)| and descendants.
New morphology concept added 846575004 |Angioedema (morphologic abnormality)|

Changes for 'On Examination' and 'Complaining of' concepts

The 'on examination' and 'complaining of' content is being returned to the UK as part of the work for the January 2021 release. As part of this work, where no suitable replacement concept existed (without the examination or complaint component of the meaning) and the clinical meaning met editorial guidelines new concepts were added. This work was done over the January 2020 and July 2020 releases.  For the July 2020 release this included the addition of 230 new concepts.  

Update 17602002 Amyloidosis (disorder) and descendants

The modeling and terming of many amyloidosis disorder concepts were updated in the 17602002 Amyloidosis (disorder) sub-hierarchy.

Reactivation of 419952004 |Dermoid cyst (disorder)|

Existing concepts using the fully specified name "Cystic dermoid choristoma" have been inactivated and replaced with new concepts using the fully specified name "Dermoid cyst of X". 

These concepts have all been inactivated:

• 441459009 |Cystic dermoid choristoma (disorder)| and all subtypes
• 416529009 |Cystic dermoid choristoma (morphologic abnormality)|
• 417137001 |Dermoid choristoma (morphologic abnormality)|

Rename FSN for concepts using 'Ecstasy' to Methylenedioxymethamphetamine

For example 296318001 |Overdose of ecstasy (disorder)|. Ecstasy is not synonymous with Methylenedioxymethamphetamine (MDMA). Where “Ecstasy” is used in FSN and Causative agent is MDMA the concept has been replaced with a new or existing concept with FSN that contains MDMA. When “Ecstasy type drug” is used in FSN, regardless of causative agent the concept is replaced with a concept with FSN for “Amfetamine and amfetamine derivative (substance).”

Remodel 397803000 |Impotence (disorder)

Due to the potentially negative connotation of the wording 'impotence' the concept 397803000 |Impotence (disorder) has been inactivated and replaced with a new concept 860914002 |Erectile dysfunction (disorder). Subtype concepts that used the word 'impotence' have also been replaced with concepts that use the term 'erectile dysfunction.'

Convergent Medical Terminologies (CMT)

New CMT concepts: 714

• Injury - 162 concepts added.
• Ophthalmology - 552 concepts added.

Procedure

New concepts for procedure hierarchy: 105

Areas of Quality Improvement for the Procedure Hierarchy

Implantation and Insertion procedures

Work commenced on content tracker IHTSDO-175. There are ongoing structural changes for the Procedure concepts related to the content tracker: It was agreed that not all Insertion and Implantation procedures are surgical. As a result, further work in the hierarchy under 129284003 |Surgical action (qualifier value)| has been undertaken for the January 2020 release and this includes:

• • Reactivation of 129338005 |Surgical implantation - action (qualifier value)|
  • Addition of a new concept 788288006 |Surgical reimplantation - action (qualifier value)|
  • Remodel of 'Reimplantation procedures' replaced METHOD = 129337000 |Reimplantation - action (qualifier value)| with new 788288006 |Surgical reimplantation - action (qualifier value)|

Work on this project will continue for future releases after January 2020.

Evaluation Procedures

• • Inactivated four duplicate concepts.
  • Inactivated six ambiguous concepts.
  • Inactivated one erroneous concept.
  • Created one new concept to replace an ambiguous concept.
  • Inactivated descriptions of sixteen concepts.
  • Removed incorrect parent for two concepts.
  • Added descriptions to fourteen concepts.

Changes to Existing Concepts in the Procedure Hierarchy

The following concepts and/or areas in the procedure hierarchy were remodeled:

• • Osteopathic manipulation techniques
  • Emergency coronary artery bypass graft
  • Tylectomy
  • Neck excision
  • Procedure on brain ventricular shunt
  • Change of diaper
  • Removal of leeches
  • Dermabrasion of facial scars
  • Triennial health exam
  • Detoxification therapy (regime/therapy)
  • Hormone therapy replacement
  • Transplantation of dura
  • Cervical biopsy
  • Excisional biopsy of cerebral meninges, percutaneous, needle
  • Suture of plexus
  • Oral fluorescence imaging
  • Administration of heavy metal antagonist

Collaboration/Harmonization Projects

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. 

The mapping and validation process has begun for an alpha release after the January 2020 International release of SNOMED CT. 

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

Global Medical Device Nomenclature Agency (GMDNA)

21 new device concepts were added to the physical object hierarchy for GMDN.

4 device concepts were inactivated.

For the GMDN mapping equivalence tables: 

• • 21 New concepts have been added to inscope and mapped.
  • 161 concepts have been modified and removed from the mapping tool as out of scope.
  • 92 concepts ave been deemed obsolete and removed from the mapping tool and flagged as out of scope.
  • 334 concepts were identified as no longer in scope for the map and have been removed. These concepts were identified as part of the Quality Improvement of the mapping equivalence tables and the monthly submissions from GMDN.

ICD-O-3.2 Update

For the January 2020 release, and based on the recent release of ICD-O-3.2 the priority has being adding new content for updated morphologies; this refers to additions to the 400177003 |Neoplasm and/or hamartoma (morphologic abnormality)| sub-hierarchy. Approximately 63 changes in the sub-hierarchy are related to the ICD-O-3.2 update analysis, including the direct addition of 25 new morphology concepts that were identified from analysis of the ICD-O-3.2 preview as missing from SNOMED CT.

Impacted concepts in the disorder hierarchy have been revised to align with any new ICD-O-3.2 morphology changes, and in many cases the addition of a relationship to the new morphology concept has resulted in the neoplasm disorder concept being defined fully. This work has included the creation of a small number of new neoplasm disorder concepts to match the new morphologies.

Descriptions with [obs] have been inactivated as outdated because they are artefacts of descriptions from the ICD-O-3 print version for their history tracking. There are two concepts and one synonym with [obs] that remain and will be addressed for the July 2020 release.

Event

New concepts added: 16

Qualifier Value

New concepts added: 88

Situation with explicit context 

New concepts added: 31

This includes 17 new concepts for 'History of X'.

Observable Entity 

New concepts added: 136

This includes 8 new concepts for insulin dose observables.

Organism

New organism concepts added: 185

• • Added new descriptions for 10 organism concepts.
  • Inactivated 9 organism concepts as duplicates.
  • Changed descriptions of two organism concepts.
    

Pharmaceutical / biologic product

Changes for Pharmaceutical / biologic product 

Inactivation of 'Over the Counter'

Concepts referring to “over the counter” status have been inactivated.

Concepts referring to regulatory status or characterization (e.g. over the counter) are out of scope for the International Release since the meaning may vary by jurisdiction and is not consistent internationally.

Vaccine Poisoning

Concepts referring to vaccine poisoning have been inactivated from the January 2020 International release and moved to the NHS extension per their request.

The notion of vaccine poisoning has persisted in ICD 10 under T50 but it is not included in ICD-11; the poisoning aspect seemingly referred to the adjuvants and carriers that are included in the vaccines as opposed to the biological component itself.

Veterinary Extension

7 concepts were moved to the Veterinary Extension. 

Social Context

New concepts added: 1

Specimen

New concepts added: 3

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 January 2020

The map provided for the January 2020  release has been updated, and now represents a complete map from SNOMED CT International release to ICD-10 2016 version.

• 1501 new concepts added
  
• Quality improvement continues and Map QA project 51 resulted in revision of 27 concepts to represent sclerosis of bypass grafts.
• Map QA project 55, Fractures without external cause advice, was completed resulting in revision of 70 concepts.
• Map QA project 60, 328 concepts have been reviewed for inconsistent map advice. The focus was the SNOMED to ICD-10 Chapter X1V Diseases of the genitourinary system (N00-N99).
  
  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

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

ICD-O Map

The maps to ICD-O-3.1 are being updated only for error correction purposes for the January 2020 release. The maps to ICD-O-3.2 are out of scope for the January 2020 release and are planned for a future release when the ICD-O-3.2 classification has been published by WHO (IARC).

As part of the initial QA process 34 ICD-O-3.1 morphology maps to grouper concepts with "- category" in the FSN were removed and assigned a 'no target' map in preparation for the ICD-O-3.2 update.

For the January 2020 release a total of 69 morphology concepts in the 400177003 Neoplasm and/or hamartoma (morphologic abnormality) sub-hierarchy were mapped. 31 were mapped to ICD-O-3.1 morphology codes and 38 assigned a 'no target' map (consisting mainly of new morphology concepts) awaiting the ICD-O-3.2 update and availability of new codes in the mapping tool. For example new concept 788565009: Indolent T-cell lymphoproliferative disorder of gastrointestinal tract (morphologic abnormality) has no target map until ICD-O-3.2 is available but the new morphology has been used to fully define the disorder concept 783565007 Indolent T-cell lymphoproliferative disorder of gastrointestinal tract (disorder).

SNOMED CT to OWL conversion and classificationThe 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 capacity within the current editing cycle, 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 SNOMED CT January 2020 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 the Alpha and Beta testing of the current release, which were resolved before the final deployment of the associated Member 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 Snomed CT January 2020 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.

Early visibility of impending change in the January 2020 International edition

Please see the following page for details of all upcoming changes planned for January 2020 and beyond:  January 2020 Early Visibility Release Notices - Planned changes to upcoming SNOMED International Release packages.

Release Notes naming convention

The Release notes naming convention has been refined to bring it in line with other documentation standards - from this release onwards the files will have the following naming format:

• • doc_SnomedCTReleaseNotes_Current-en-US_INT_[date].pdf

   Instead of the previous underscore after "Current":

• • doc_SnomedCTReleaseNotes_Current_en-US_INT_[date].pdf

Document links

All links provide information that is correct and current at the time of this Release.  Updated versions may be available at a later date, but if so these will need to be requested from the relevant SNOMED International teams.