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.
This document provides a summarized description of the content changes included in the July 2018 release of SNOMED Clinical Terms® (SCT) International Release.
It also includes technical notes detailing the known issues which have been identified. 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.
This document is available alongside the July 2018 International Edition release.
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.
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 2018 International Edition release.
Continuous quality improvement and enhancement of existing content is ongoing based on requests received via the Content Request System (CRS). A review of pre-coordination patterns has been undertaken to assist with the progression of CRS tickets that had been placed on hold. 35 patterns have had final decisions made and the corresponding CRS tickets progressed accordingly. Information on the pattern decisions may be found in the SNOMED CT Editorial Guide
The July 2018 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) and Orphanet to add new content to SNOMED CT.
Additionally a process of Quality Improvement and project-driven changes have resulted in new content additions and enhancements to existing content detailed below.
Reminder Inactivation reason of LIMITED/WAS A will no longer be allowed for any content after the July 2018 release. The WAS A association refset will not be updated thereafter. Background In 2015, a proposal was made to inactivate 159083000 |WAS A (attribute)| relationship and stop updating the 900000000000528000|WAS A association reference set (foundation metadata concept)| at the Editorial Advisory Group. Since these recommendations were made, a formal proposal for the technical approach to batch updating the terminology was created and a notice of the proposed inactivation sent to the Community of Practice. The implementation of changes was postponed following feedback on utility for implementation and the potential impact to customers who were still using RF1. The matter was discussed again at the meeting of the Editorial Advisory Group in Bratislava in October 2017. Since the requirements and potential issues can be addressed by deriving such information from the RF2 release format, the recommendation is to proceed the decision after the July 2018 release. |
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A total of 6494 new concepts were added
SCT Statistics | New concept additions |
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SNOMED CT Concept (SNOMED RT+CTV3) | 6494 |
Body structure (body structure) | 357 |
Clinical finding (finding) | 1203 |
Event (event) | 2 |
Observable entity (observable entity) | 60 |
Organism (organism) | 182 |
Pharmaceutical / biologic product (product) | 3053 |
Physical object (physical object) | 88 |
Procedure (procedure) | 659 |
Qualifier value (qualifier value) | 224 |
Record artifact (record artifact) | 5 |
SNOMED CT Model Component (metadata) | 10 |
Situation with explicit context (situation) | 64 |
Social context (social concept) | 27 |
Specimen (specimen) | 2 |
Staging and scales (staging scale) | 21 |
Substance (substance) | 537 |
A total of 32889 changes were made to existing content
SCT Improvement Statistics to Existing Concepts | Number |
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Total number of changes | 32889 |
Change to stated concept definition | 20126 |
Change to inferred concept definition | 27970 |
Change in concept definition status from Primitive to Sufficiently Defined | 7997 |
Description change | 10691 |
Inactivated concepts | 6955 |
Inactivated descriptions | 9256 |
Reactivated concepts | 16 |
Advance Notice Planned inactivation of 123005000 |Part of (attribute)| attribute and relationships in the January 2019 release |Part of| relationships have only been included in the inferred relationship file. They are not actively maintained because they are additional relationships rather than defining relationships. The new anatomy concept model has introduced different kinds of 'part of' relationships, e.g. |All or part of|, |Constitutional part of|, |Lateral half of|, |Regional part of|, and |Systemic part of|. The modeling Advisory Group has recommended inactivation of 123005000 |Part of (attribute)| attribute and relationships in the January 2019 release. It will be replaced by a new attribute |Proper part of| to represent defining relationships where 'part is not equal to whole'. The new anatomy model will be implemented in future releases when the required description logic enhancements are implemented. |
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New anatomy concepts: 357
Updates have been made to 109 concepts to conform with the new editorial guidance on the naming convention for digits of hand and foot.
Updates have been made to concepts for skin and/or subcutaneous tissue to conform to the editorial guidance on the naming convention for conjunction and disjunction.
New concepts for clinical findings and disorders: 1203
Work completed on the following Content Projects:
IHTSDO-451 - Has definitional manifestation.
Work commenced on the following Content Projects:
Other content quality improvements:
Added a new sufficiently defined concept of 763597000|Hereditary ataxia (disorder)| resulting in changes to 40 concepts.
36 new concepts added for genetic diseases which were not part of the Orphanet project.
Remodeling and re-terming of 110288007 |Joint tenderness (finding)|. Redefined Joint tenderness as IS_ A Tenderness (finding) + finding site=joint structure and all of the specific joint tenderness concepts using the same pattern. Renamed all joint tender(ness) concepts as Tenderness of x joint (finding).
Inactivated 202936005 |Ganglion and cyst of synovium, tendon and bursa (disorder) and used an analogous approach to inactivate the descendants with new replacement concepts.
Remodel 63491006 |Intermittent claudication (finding)| hierarchy. Added due to 86341008 |Vascular insufficiency (disorder)|. Removed parent of 22253000 |Pain (finding)| and added parents of 427935006 |Pain relief by rest (finding)| and 427341007 |Pain provoked by exertion (finding)|.
Review and remodel 11 viral disorder and related concepts.
Inactivated out of scope |Allergy to X (disorder)| concepts, as identified by the Allergy/Hypersensitivity and Intolerance Clinical Reference Group.
Review and remodel of 520 fracture of lower limb concepts using a proximal primitive parent and creating stated defining relationships for those which were previously inferred relationships.
Intussusception disorder concepts were remodeled using the proximal primitive parent modeling approach with two relationship groups capturing the invagination and obstruction morphologic abnormalities of this disorder. The concept Intussusception (morphologic abnormality) was inactivated as a duplicate of Invagination (morphologic abnormality).
New CMT concepts: 215
These were added across 3 domains:
New concepts for procedure hierarchy: 659
Diagnostic imaging - 32 requests were received for new imaging procedure concepts with various imaging modalities.
Work completed on the following Content Projects:
Other content quality improvements:
Implemented changes related to 208 client requests mainly in the area of laboratory procedure and microbiology reporting. Changes are implemented in the following hierarchies: Organism (including creation of 133 new organism concepts), Specimen, Evaluation procedure, Finding, Substance, and Technique.
Updated naming for Streptococcus pneumoniae serotypes by specifying the nomenclature system (Danish vs. American) which resulted in changes for 214 concepts (including addition, inactivation or change in description) in the following hierarchies: Organism, Substance, and Evaluation procedure.
As a result of collaboration with Orphanet (http://www.orpha.net/consor/cgi-bin/index.php) 473 new SNOMED CT concepts have been created to represent rare diseases in the disorder hierarchy.
64 new SNOMED CT concepts created and mapped in the Physical object hierarchy to support the GMDN collaboration agreement.
New concepts added: 2
Work commenced on the following Content Projects:
New concepts added: 224
Content quality improvements:
Replaced existing ambiguous top-level concept 258666001 |Unit (qualifier value)| with new 767524001 |Unit of measure (qualifier value)| concept. To support modeling of clinical drug concepts in the 763158003 |Medicinal product (product)| hierarchy, created new 767525000 |Unit (qualifier value)| concept as descendant of 259026009 |Miscellaneous unit (qualifier value)|.
New organism concepts added: 182
Work commenced on the following Content Projects:
Other content quality improvements:
For further details on the planned changes in this area, please refer to the Drug Model Working Group Directory section. Please note, you may have to register for Confluence user account in order to access this project and the relevant links below. |
The following changes will be included in the 2018-July International Release.
New hierarchies |
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New semantic tags |
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New attribute types |
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Grouper concepts representing disposition, intended site, and/or structure |
New high level grouper concepts created as an incremental improvement with additional subtypes to be added in future releases:
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Product role concepts |
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Medicinal product (MP) concepts |
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Medicinal product form (MPF) concepts |
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Clinical drug (CD) concepts | CD-containing precisely concepts sufficiently defined by modeling to proximal primitive concept, adding defining attributes, and updating descriptions per editorial guidelines (n≈ 4850). Includes the following attributes:
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Documentation |
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15 concepts were moved to the Veterinary Extension.
New concepts added : 64
143 concepts using the pattern 'OFFERED' or 'NOT OFFERED' were inactivated.
Addition of new concepts for transplant donor and recipient Epstein Barr virus status.
Work continuing on the following Content Projects:
26 new concepts were added as a subtype of 14679004|Occupation (occupation)|.
Review of 11 of assessment scale concepts for duplicates or correctness.
Addition of 96 assessment scale, observable entity and procedure concepts to support use of assessment scales.
The following changes will be included in the 2018-July International Release.
Disposition groupers |
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Structural groupers |
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Chemical element groupers |
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Combined groupers |
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Is modification of attribute |
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Role groupers |
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General content updates |
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Documentation |
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Other content quality improvements:
Inactivation of 417881006|Radiopharmaceutical agent (substance)| which was a primitive concept with three stated subtypes and not a substance but a role of a substance. After the inactivation, there was a hierarchy review starting at 33638001|Isotope (substance)| involving approximately 850 concepts.
Creation of new terming document, use of INN terming where possible. Alignment of content with new terming
Removal of caret "^" for superscript
For example:
Before = 24511001|Technetium Tc^99m^ succimer (substance)
After = 24511001|Technetium (99m-Tc) succimer (substance)
Substances were moved under more specific supertypes where possible. Removal of formatting carets
Identified nuclear medicine procedures using a "substance grouper" as an attribute value but refer to a specific substance in the FSN. Remodeled with a specific substance approximately 93 concepts
Concept 371572003|Nuclear medicine procedure (procedure)| has been sufficiently defined. A hierarchy review has been started to review terming, use of correct radioisotopes, and inactivation of concepts containing additional context outside of the actual procedure.
For further details on the planned changes in this area, please refer to the Substances project. Please note, you may have to register for Confluence user account in order to access this project and the relevant links above. |
The first release of the OWL reference sets
As an essential part of SNOMED CT Logic Profile Enhancements, two OWL refsets have been developed to represent logic definitions following the international standard of OWL 2 Web Ontology Language.
The OWL Ontology reference set includes essential metadata information about an ontology, such as, namespaces, ontology URI and ontology version URI.
The OWL Axiom reference set includes only property axioms, such as property chains, transitive properties, and reflexive properties, that cannot be fully represented by the RF2 stated and inferred relationship files. The limited scope of the first release is a response to the Community of Practice Consultation happened early this year, which allows sufficient time for users to develop and update their tooling and systems.
The content from the OWL reference sets must be included for all applications that utilise the description logic (DL) reasoning services to ensure correct inferences. These property axioms are required for classification by DL reasoners to support the drug, substance, and anatomy projects and other clinical content depend on them. Extensions can update the refsets by following the OWL reference sets specification.
Following the recommendation from the Modeling Advisory Group, the full representation of all logical definitions and other key DL features, such as additional axioms and GCIs (General Concept Inclusion), will be included in the OWL axiom refset in the January 2019 release. A reference implementation by SNOMED International was demonstrated at the April business meeting. All software systems implemented DL reasoning services need to be updated to use the OWL axiom refset that is the only source of truth for logic definitions from 2019.
Updates to the RF2 relationship files
There are no changes to the stated relationship file for the July 2018 release. However, the stated relationship file must be used in conjunction with the OWL refsets for the DL reasoning services.
In the January 2019 release, the stated relationship file will be replaced by the OWL axiom refset that includes all logical definitions and other features specified in the SNOMED CT logic profile specification. The stated relationship file will NOT be included in the international release; however, it may still be available on request to support migration to the OWL axiom refset.
The inferred relationship file will maintain the same format and structure, though it is no longer containing all necessary and sufficient conditions. The inferred relationship file is represented in Necessary Normal Form for distribution of relationships. It is a collection of all the necessary conditions and represents a subset of the full semantics from the 2018 July release and onwards. Most users will benefit from the improvements in the inferred relationships without requiring changes to their existing systems.
A set of documentations has been developed to support the Logic Profile Enhancements.
14 new MRCM rules and 10 updates to the existing MRCM in the MRCM refsets and authoring platform.
The SNOMED CT to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (© World Health organisation 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 Centres.
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_20180731.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)|.
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.
The map provided for the July 2018 release has been updated, and now represents a complete map from SNOMED CT International release to ICD-10 2016 version.
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
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
There are 5 updates for the ICD-O Morphological abnormality map in July 2018 release.
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.
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 2018 International edition, the following Known Issues were identified, and agreed to be resolved in the next editing cycle (to be published in July 2018):
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 - in this case the July 2018 International Edition. 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 2018 International edition can be found here:
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
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.
Please see section "2.3.1 Logic Profile Enhancements" above for full details of the reason behind the introduction of these new refsets. The technical implication is that two new files will be included in each section of the International Release package (Full, Snapshot and Delta):
The naming convention was decided upon in order to best describe the content of each refset file. It was thought to be misleading to include ’stated’ at the start of the file names because the OWL Ontology Refset contains only metadata for an ontology, which is always the same no matter whether the ontology contains axioms before or after classification. In addition, the word 'stated' is redundant to 'axiom'. Finally, the 'sct2' filetype is utilised to indicate that the axioms are not a derivative product.
The decision was taken to place the files in the "Terminology" folder in the release package (as opposed to the "Refset" folder), because these files are designed to eventually replace the Stated relationship files, and therefore contain core content which needs to be included in the Terminology folder.
In January 2017 the original OWL conversion script (a.k.a. the "Spackman OWL script") was removed from the International Edition package, and has since been published as a separate artefact alongside each Release.
Because this script does not recognize the two new OWL refsets (see section 3.3.2 of these Release Notes), the Terminology Release Advisory Group has determined that the script should no longer be distributed.
Going forward, Release Notes will now include a link to the new open source OWL conversion toolkit that can be found in the following repository (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.
The Terminology Release Advisory Group has confirmed that there should be no impact from removing this almost entirely static document from the International Edition release package, and hosting it instead in a Confluence Page. From the July 2018 International release then, we will deprecate this file (doc_Icd10MapTechnicalGuideExemplars_[date].xlsx) from the Release package, and instead provide a link in the Release Notes to the new Confluence Page. Please see section 2.4.1.3 above for the relevant link.
Please see the following page for details of all upcoming changes planned for January 2019 and beyond: Early Visibility - Planned changes to upcoming SNOMED International Release packages
Replacement of the Stated Relationship files with the new OWL Axiom refset files
In the January 2019 release, the stated relationship file will be replaced by the OWL Axiom refset files, that will include all logical definitions and other features specified in the SNOMED CT logic profile specification. The stated relationship file will NOT be included in the international release; however, it may still be available on request to support migration to the OWL Axiom refset.
Users should carefully analyse any potential impact to their systems (upload routines, etc) and make provisions for these changes urgently (if not already done), in order to prevent any issues when these changes come into effect in January 2019. Please contact SNOMED International at support@snomed.org with “OWL Axiom refset files implementation question” in the subject line. |
The inferred relationship file will maintain the same format and structure, though it will no longer contain all necessary and sufficient conditions. The inferred relationship file is represented in Necessary Normal Form for distribution of relationships. It is a collection of all the necessary conditions and represents a subset of the full semantics from the 2018 July release and onwards. Most users will benefit from the improvements in the inferred relationships without requiring changes to their existing systems.
A set of documentations has been developed to support the Logic Profile Enhancements.
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.
NOTE: To access any of the links in the pdf document, please visit the Release Notes online here: |
Approvals
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Draft Amendment History
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