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 2020 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 2020 International Edition 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 2020 International Edition release.

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 2020 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 at this link https://confluence.ihtsdotools.org/display/DOCICD10

2.2. Important - Content Changes Introduced After the July 2020 Member Release, and before the July 2020 Production Release

Two additional concepts (plus their related components) were added to the July 2020 release after the Member release on 30 June 2020.  They are therefore included in the final, Public release of the July 2020 International Edition.

The two new concepts are detailed elsewhere in these release notes however for information the new concepts are:

• 895231008|Not detected in pooled specimen (qualifier value)|
• 890195008|International Health Terminology Standards Development Organisation Global Patient Set module (core metadata concept)|
  
  
  

2.3. COVID-19

An INTERIM International Edition Release was produced in March 2020 as part of the ongoing global effort to tackle the Coronavirus outbreak and included the updated Coronavirus descriptions for Members and implementers.

A further set of new concepts have been added for the July 2020 release

Updates about content relating to COVID-19 can be found here SNOMED CT COVID-19 Related Content 

Any concepts in scope for SNOMED CT to ICD-10 mapping have been mapped and adhere to the World Health Organization current guidelines.

2.4. Content Quality Improvement

2.4.1. 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.

2.4.1.1. Abdomen/Pelvis

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. Revision of the inguinal region, anal structures and vaginal structures have been implemented in order to address some historical sub-optimal classification results.
Further detail can be found at https://docs.google.com/document/d/1gxkcEYf89eJl0RJG8-S2w4zOdpF8R2sn5SHx7InWxZI/edit?usp=sharing

2.4.1.2. Coronary artery

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

2.4.1.3. Cardiac ventricle

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

2.4.1.4. Jaw region

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

2.4.1.5. Peripheral artery

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.

2.4.1.6. Mediastinum

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.

2.4.1.7. 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.

2.4.1.8. Reference set updates

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

2.4.2. Clinical finding

New concepts added for clinical finding hierarchy: 2064

2.4.2.1. 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.

2.4.2.2. 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.

2.4.2.3. 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.

2.4.2.4. 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.

2.4.2.5. 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).

2.4.2.6. 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.

2.4.2.7. Update Allergy to substance (finding)

As part of the QI project review of the 419199007 |Allergy to substance (finding)| sub-hierarchy and per the Allergies Clinical Reference Group recommendation, the concepts in this sub-hierarchy that represent allergy to "role groupers" and "Structure + role groupers" are being  inactivated starting from the July 2020 release. Examples of these concepts are provided below:

• • 294450008 Allergy to anthelmintic agent (finding)
  • 294461000 Allergy to antibacterial drug (finding)

2.4.2.8. Content Tracker Project Updates

Work on hold on the following Content Project:

• IHTSDO- 393 Diabetes Complications - The Diabetes Project Group comprises practicing clinicians. As a result of the COVID-19 pandemic the majority of the participating clinicians have been drafted into supporting the response to this health care crisis. Consequently this project has been put on temporary hold until the pandemic is under control and healthcare staff are able to return to their normal duties. 

Work completed for the following Content Project: 

• IHTSDO-1157 Distinction between Pain and Tenderness. Improvement in the modeling of the Tenderness (finding) sub-hierarchy. 

2.4.2.9. Improve modeling for 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)|

2.4.2.10. 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.  

2.4.2.11. Update 17602002 Amyloidosis (disorder) and descendants

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

2.4.2.12. 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)|

2.4.2.13. Rename FSN for concepts using 'Ecstasy' to Methylenedioxymethamphetamine

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).”

2.4.2.14. Remodel 397803000 |Impotence (disorder) and descendants

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.'

2.4.2.15. New concept 840358001 |High body weight (finding)| and realignment of subtypes

A new concept 840358001 |High body weight (finding)| has been added and has 2 subtypes that are siblings:

• 414915002 |Obese (finding)|
• 238131007 |Overweight (finding)|

The two latter findings of 'Obese' and 'Overweight' are mutually exclusive terms in the classification of BMI. 

2.4.2.16. New concepts - Mental health

2 new concepts have been added after liaison with the Mental and Behavioural Health Clinical Reference Group:

• 'Depressive episode' has been removed as a synonym on 35489007 |Depressive disorder (disorder)|.
• New concept has been added 871840004 |Episode of depression (finding)|.
• New concept added: 833326008 |Cortical vascular dementia (disorder)|

2.4.3. Convergent Medical Terminologies (CMT)

New CMT concepts: 714

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

2.4.4. Procedure

New concepts for procedure hierarchy: 299

2.4.4.1. Implantation and Insertion procedures

Work continues on content tracker IHTSDO-175. There are ongoing structural changes for the Procedure concepts related to the content tracker. Work on this project will continue for future releases after July 2020.

2.4.4.2. Content Inactivation - Anesthesia

These concepts have been inactivated from the International release and moved to the US extension:

• 67902001 |Anesthesia for a normal healthy patient (procedure)|
• 23102000 |Anesthesia for a patient with mild systemic disease (procedure)|
• 22211001 |Anesthesia for a patient with severe systemic disease (procedure)|
• 112989003 |Anesthesia for a moribund patient requiring operation (procedure)|
• 71191009 |Anesthesia for a patient with severe systemic disease, life threatening (procedure)| 
  

2.4.4.3. Content Inactivation - Monitoring

These concepts have been inactivated from the International release and moved to the UK extension:

• 391023009|Osteoporosis - no treatment (regime/therapy)|
• 391030003|Osteoporosis - no treatment response (regime/therapy)|
• 391028000|Osteoporosis - treatment response (regime/therapy)|
• 391003008|Osteoporosis monitoring administration (regime/therapy)|
• 391004002|Attends osteoporosis monitoring (regime/therapy)|
• 391006000|Osteoporosis monitoring default (regime/therapy)|
• 391012005|Osteoporosis monitoring deleted (regime/therapy)|
• 391007009|Osteoporosis monitoring first letter (regime/therapy)|
• 391008004|Osteoporosis monitoring second letter (regime/therapy)|
• 391011003|Osteoporosis monitoring telephone invitation (regime/therapy)|
• 391009007|Osteoporosis monitoring third letter (regime/therapy)|
• 391010002|Osteoporosis monitoring verbal invitation (regime/therapy)|

2.4.4.4. Evaluation Procedure

• New evaluation procedure concepts - 10 (respiratory procedures, specimen processing and laboratory panels).
• Concept inaction - 13 (inactivated due to duplication or ambiguity).

2.4.5. Collaboration/Harmonization Projects

2.4.5.1. 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 alpha release is now available for feedback, for more information please see April 2020 SNOMED CT Orphanet Simple Map package ALPHA release available

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

2.4.5.2. ICD-11 Update

A total of 593 new concepts were added for the July 2020 release.

2.4.5.3. Global Medical Device Nomenclature Agency (GMDNA)

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

 For the GMDN mapping equivalence tables: 

• 62 new concepts have been added to in scope and mapped.
• 156 concepts have been modified and removed from the mapping tool as out of scope.
• 95  concepts have been deemed obsolete and removed from the mapping tool and flagged as out of scope.

2.4.5.4. ICD-O-3.2 Update

A full Impact analysis of both updating the existing SNOMED CT content and updating the current ICD-O-3.1 map has been carried out. In particular this relates to changes to the 400177003 |Neoplasm and/or hamartoma (morphologic abnormality)| sub-hierarchy in SNOMED CT. The impact analysis utilized the final IACR ICD-O-3.2 (WHO IARC) morphology code listing and the new pdf changes documents on their website (http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577).

For the July 2020 release only minor changes have been made, and 14 new morphologies have been added to the 108369006 |Neoplasm (morphologic abnormality)| sub-hierarchy.

Note - The published maps to ICD-O-3.1 are being updated only for maintenance purposes for the July 2020 release. The maps to ICD-O-3.2 are out of scope for the July 2020 release and are planned for a future release.

2.4.6. Event

New concepts added: 4

2.4.7. Qualifier Value

New concepts added: 65

2.4.8. Occupation

Concepts representing "other" occupations e.g. 79445009 |Other clerk (occupation)| have been inactivated as ambiguous as these represent classification constructs.

2.4.9. Situation with explicit context 

New concepts added: 129

2.4.10. Physical object

New concepts added: 89

• Approximately 200 device concepts in the physical object hierarchy were modeled with the new device attributes in the areas of breast implants, shunts, stent, and cardiac valve prosthesis. Some of these concepts also had FSN and description changes.
• 25 concepts in the physical object hierarchy were inactivated.
• Approximately 630 attribute-value relationships were added to the physical object hierarchy including device characteristic such as sterility, absorbability, and custom-made.
• Editorial guidelines developed and documented and noted content updated accordingly. The guidelines are found on the project space: Reference Documentation - Devices (Please note, you may have to register for Confluence user account in order to access this project and the relevant link).
  

2.4.11. Specimen

New concepts added: 8

Concepts inactivated: 2

2.4.12. Observable Entity 

New concepts added: 117

• 30 new concepts were added in the areas of novel coronavirus detection, insulin rates and doses, test due dates, minimum alveloar concentration.
• Estimate intake of X = 30 concepts new concepts
• Measured intake of X = 30 concept new concepts
• Proportion of X  = 3 new concepts
• Target = 4 new concepts

2.4.13. Organism

New organism concepts added: 135.

Updated descriptions for 60 concepts.

2.4.14. Pharmaceutical / biologic product

2.4.15. Veterinary Extension

23 concepts were moved to the Veterinary Extension.

2.4.16. Metadata concept

In order to support the upcoming RF2 version of the GPS (Global Patient Set) refset, the GPS requires its own moduleID.

A new concept has been added to support this use case 890195008|International Health Terminology Standards Development Organisation Global Patient Set module (core metadata concept)|

2.6.1.1. 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. 

2.6.1.2.  Mapped content for July 2020

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

• 2223 new concepts added
  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

2.6.1.3. 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

2.6.2. ICD-O Map

For the July 2020 release only minor changes have been made, and 14 new morphologies have been added to the 108369006 |Neoplasm (morphologic abnormality)| sub-hierarchy.
The published maps to ICD-O-3.1 are being updated only for maintenance purposes for the July 2020 release. The maps to ICD-O-3.2 are out of scope for the July2020 release and are planned for a future release.

2.6.3. 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 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 July 2020 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 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 July 2020 International edition can be found here:

3.2.1. Technical updates

3.2.1.1. 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.

3.2.1.2. New Configuration file in the RF2 package, containing Release Metadata 

A new file will be included in the July 2020 International Edition (and all subsequent releases), containing metadata about the Release package itself.  This has been created in conjunction with feedback from the community, and as such will initially contain the following fields:

• effectiveTime
  
• deltaFromDate
  
• deltaToDate
  
• languageRefset(s)
  
• humanReadableLanguageRefset(s)
  
• licenceStatement
  

The file will be in .JSON format, to ensure that it is both machine-readable and human-readable.  It will be 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 anyone has 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.  

3.2.1.3. Additional Rollup Delta Release package

For those users who did NOT use the March 2020 Interim International Edition release in their systems, the advise on bringing systems up to date is as follows:

1. The best option is to first apply the March 2020 Interim release Delta files (relative to the January 2020 release), and after that apply the official July 2020 Delta files (relative to the March 2020 Interim release).
2. If this is not feasible, then please use the July 2020 International Edition additional Rollup Delta package - please see the Release Notes for full details:
   1. https://confluence.ihtsdotools.org/display/RMT/SNOMED+CT+July+2020+International+Edition+additional+Rollup+Delta+package+-+SNOMED+International+Release+notes

3.2.1.4. Early visibility of impending change in the July 2020 International edition

Please see the following page for details of all upcoming changes planned for July 2020 and beyond:  https://confluence.ihtsdotools.org/display/RMT/July+2020+Early+Visibility+Release+Notice+-+Planned+changes+to+upcoming+SNOMED+International+Release+packages.

3.2.1.5. 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

3.2.1.6. 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.