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© 2021 International Health Terminology Standards Development Organisation.  All rights reserved.  SNOMED CT® was originally created by the College of American Pathologists.

This document forms part of the International Edition release of SNOMED CT® distributed by International Health Terminology Standards Development Organisation, trading as SNOMED International, and is subject to the SNOMED CT® Affiliate License, details of which may be found at

No part of this document may be reproduced or transmitted in any form or by any means, or stored in any kind of retrieval system, except by an Affiliate of SNOMED International in accordance with the SNOMED CT® Affiliate License. Any modification of this document (including without limitation the removal or modification of this notice) is prohibited without the express written permission of SNOMED International.

Any copy of this document that is not obtained directly from SNOMED International [or a Member of SNOMED International] is not controlled by SNOMED International, and may have been modified and may be out of date. Any recipient of this document who has received it by other means is encouraged to obtain a copy directly from SNOMED International [or a Member of SNOMED International. Details of the Members of SNOMED International may be found at].

Page At A Glance

Table Of Contents



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 2019 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 2019 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 2019 International Edition release.

Content Development Activity


Continuous quality improvement and enhancement of existing content is an ongoing process by SNOMED International for every release. The July 2019 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


Inactivation reason of LIMITED/WAS A is not allowed for any content after the July 2018 release. The WAS A association refset has not been updated thereafter.


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 approved, 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 with the decision for implemenation after the July 2018 release. 

Content Quality Improvement

SCT StatisticsNew concept additions
Body structure (body structure)451
Clinical finding (finding)1206
Event (event)6
Observable entity (observable entity)32
Organism (organism)141
Pharmaceutical / biologic product (product)1929
Physical object (physical object)44
Procedure (procedure)215
Qualifier value (qualifier value)149
Record artifact (record artifact)7
SNOMED CT Model Component (metadata)13
Situation with explicit context (situation)86
Social context (social concept)1
Specimen (specimen)4
Staging and scales (staging scale)2
Substance (substance)125

SCT Improvement Statistics to Existing ConceptsNumber
Total number of changes44638
Change to stated concept definition30254
Change to inferred concept definition25842
Change in concept definition status from Primitive to Sufficiently Defined 2400
Description change2461
Inactivated concepts3142
Inactivated descriptions1700
Reactivated concepts13


New anatomy concepts: 451

The initial review was completed for over 12,000 hierarchical relationships that are different between the production release and new anatomy model for body structures. For this release, the focus for the Anatomy project is quality improvement for the cardiovascular, digestive and genitourinary systems. Review of the remaining systems is planned for the 2020 January release.

    • Changes to hierarchical relationships:
    • Cardiovascular system: 1,363   
    • Digestive system: 906
    • Genitournary system: 510
    • Reviewed potential impact to other hierarchies e.g. disorder, procedure and addressed most issues.
    • Cardiovascular system: over 8,600 
    • Digestive system: over 7,200
    • Genitournary system: over 6,800
    • In the body structure hierarchy a branch of a specified artery is not subordinate to its origin but has an IS_A relationship to a more regional artery. Any relationships that did not fulfil this rule have been corrected.
    • Similarly in the body structure hierarchy a tributary of a specified vein is not subordinate to the vein it drains in to, but has an IS_A relationship to a regional vein that covers the entire anatomical boundaries of every tributary of that vein. Any relationships that did not fulfil this rule have been corrected.
    • In the body structure hierarchy the vascular structure of an organ is composed of vessels that lie within and are part of the organ and the vessels that lie outside which supply it. So the kidney has glomerular arterioles within the kidney and a renal artery and renal vein that supply and drain the kidney. These relationships have been implemented for most organs and the remaining organs e.g. liver, stomach will be rationalized in the subsequent release.
    • In the body structure hierarchy a distinction has been made between the abdominopelvic structure and its constituent components: structures of the abdomen proper and those subsumed by pelvic structure. In general clinical concepts using the word ‘abdominal’ usually mean ‘abdominopelvic’ but in some specific circumstances a distinction is required; for example the uterus is located in the true pelvis (pelvis major) and not within the abdomen proper.
    • Skin appendage structures have been placed under skin structure.
    • Revision made to digital nerves of toe and its subconcepts.
    • Updates to free margin of eyelid and its subconcepts.
    • New additions of lumen concepts for the gastrointestinal tract and joint region concepts to support work for the Quality Initiative.
    • Updated content for the internal part of the mouth region.
    • Revision of subconcepts of lateral half of face.
    • Updated and validated release file for the lateralizable body structure reference set.
    • Updated and validated release files for the SEP refsets.

Clinical finding

Advance Notice 

Planned changes to 'Co-occurrent and due to' pattern.

During the implementation of the new Description Logic features a conflict was uncovered between the modeling of 'Co-occurrent and due to' and General Concept Inclusions (GCIs). This has resulted in the need to reconsider the modeling of "Co-occurrent and due' and update the Editorial Guide for this area.

There are a number of new concepts in the July 2019 release that are based upon the existing guidance for 'Co-occurrent and due to'. The plan is to update the Editorial Guide and all concepts that are currently modeled as 'Co-occurrent and due to' starting from the July 2019 release.

New concepts for clinical findings and disorders: 2114

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 the July 2019 release. 

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.

The following subhierarchies of the Clinical Finding hierarchy were remodelled to the proximal primitive parent resulting in changes to inferred relationships.

      • Fracture 
      • Bacterial infectious disease
      • Disease caused by parasite
      • Sexually transmitted disease
      • Chronic inflammatory disease
      • Aneurysm
      • Arthritis
      • Open wound
      • Closed wound
      • Bite wound
      • Congenital malformation
      • Protozoan infection
      • Closed wound
      • Viral disease
      • Hernia of abdominal cavity - Structural improvement of subtypes of the concept 52515009 |Hernia of abdominal cavity (disorder)|. Further work will be undertaken in a subsequent release on the combined disorders where gangrene and/or obstruction is present due to a hernia as well as incisional hernias.
      • Burn - Inactivation of burn concepts containing "with loss of body part" and "without loss of body part" approximately 161 concepts.
      • Abrasion - As a result of changes made during the QI project, there are now 2 concepts which have the same preferred term. 
        781488002 |Abrasion of foot (finding)
        211402004 |Abrasion of foot (disorder)
        782201009 |Abrasion (finding)|
        399963005 |Abrasion (disorder)|
        These concepts will be addressed as part the QI project for the July 2019 release.

Total count of changes for the QI project:

      • Stated: A total of 12595 concepts had changes made to the Stated relationships in their models.
      • Inferred: This resulted in 20012 concepts affected by inferred changes.
      • Subsequent review of the Fracture hierarchy of 151 concepts identified no impact upon the previously published maps to ICD-10.
      • Subsequent review of the Burn hierarchy of 375 concepts identified no impact upon the previously published maps to ICD-10.

Changes to Allergy Content

Approximately 2,000 concepts relating to hypersensitivity conditions have been remodeled to conform with new editorial guidance (excluding hypersensitivity reaction):

      • Hypersensitivity/Allergy/Non-allergic hypersensitivity condition classes defined using General Concept Inclusion (GCI) axioms in order to encompass disorders, dispositions and processes (reactions).
      • Propensity to adverse reaction and Allergic disposition moved from disorders to findings. The concepts were remodeled using the proximal primitive parents with a role group consisting of 719722006 |Has realization (attribute)| with value of allergic process or its subtype. The new convention for descriptions are Hypersensitivity/Allergy/Non-allergic hypersensitivity to X (finding).
      • New Allergic disorder (disorder) hierarchy representing abnormal structures. The allergic disorders are modeled by associated inflammation morphology + allergic process or subtype + finding site X e.g. Allergic rhinitis).
      • The contact hypersensitivity conditions have been remodeled using the new concepts for Immunoglobin E-mediated allergic contact hypersensitivity process (qualifier value) and Non-immunoglobin E-mediated allergic contact hypersensitivity process (qualifier value).
      • New Intolerance to substance (finding) hierarchy created under Propensity to adverse reaction (finding) as a sibling of Hypersensitivity disposition (finding).
      • 414029004 |Disorder of immune function (disorder)| is remodeled and defined by using a pathological process of 769247005 |Abnormal immune process (qualifier value). As a result, it subsumes allergic disorders and allergic reactions.
      • Pseudoallergy condition and Pseudoallergy disposition renamed to Non-allergic hypersensitivity condition (finding) and Non-allergic hypersensitivity disposition (finding) and they have been remodeled following the new concept model.
      • Inactivation of “Allergy to X" concepts where X is a modification of a base substance and replacement with Allergy to the base substance.

As the result of Allergy project requirements, the following top level groupers/Allergen classes in substance hierarchy were inactivated and their children assigned to appropriate structural and/or functional parents :

      • 414052000 | Drug allergen by structure |
      • 414057006 | Drug pseudoallergen|
      • 414053005 | Drug allergen or pseudoallergen|
      • 414058001 | Drug pseudoallergen by function|

Note: Other top level groupers (as specified in project Allergies-19) will be inactivated in the future releases.

Any maps from SNOMED CT to ICD-10 impacted by this Quality Initiative have been reviewed and updated.

Work commenced on the following Content Projects:

      • IHTSDO- 393 Diabetes Complications: The Diabetes Project Group has begun its work on reviewing the current SNOMED CT Diabetes Mellitus disorder concepts. The group is small but is truly international and each member is currently seeking to engage with diabetes specialists within their geographical zone in order to ensure international interoperability within this domain.
      • IHTSDO-41 Modeling of 'X' in remission - Approximately 170 disorder in remission concepts can now be found in the hierarchy 765205004 | Disorder in remission (disorder) | as well as the hierarchy relating to the underlying disorder.

Other content quality improvements:

      • 371598009 |Heberden's node (finding)| changed to disorder. 201827009 |Heberden's nodes with arthropathy (disorder)| inactivated. 80400009 |External hyperostosis (morphologic abnormality)| moved from under 13814009 |Hypertrophy of bone (morphologic abnormality)| to 4147007 |Mass (morphologic abnormality)| and Heberden node (disorder) remodeled. The result is that Heberden node (disorder) is no longer a subtype of 298745009 |Hypertrophy of upper limb (finding)| but is now a subtype of 416189003 |Exostosis (disorder)|.
      • Intrinsic vs. Extrinsic Asthma - changes made: 
        • 424643009 |Immunoglobulin E-mediated allergic asthma (disorder)| removed synonym "Extrinsic asthma" as semantically non-equivalent and "refers to" 389145006 |Allergic asthma (disorder)|. 
        • 389145006 |Allergic asthma (disorder)| - added preferred term. 
        • "Extrinsic asthma" removed synonyms "Allergic atopic asthma" and "Atopic asthma" and "refers to" 424643009 |Immunoglobulin E-mediated allergic asthma (disorder)|. 
        • 424643009 |Immunoglobulin E-mediated allergic asthma (disorder)| added synonyms "Allergic atopic asthma" and "Atopic asthma".
      • Acquired disorder - Approximately 124 concepts were edited to continue with the work to remove the precoordinated morphology and replace with a single morphology and the occurrence "767023003|Period of life beginning after birth and ending before death (qualifier value)" in the relationship group. 
      • Remodeling of Joint instability - approximately 156 concepts remodeled using approach: FSN: |Instability of X (finding)|, Is a: 404684003|Clinical finding (finding), finding site: X body structure, relationship group: Interprets: 299444001 |Stability of X (observable entity)|/ Has interpretation: 263654008|Abnormal (qualifier value).
      • Additions and improvements in areas of suspected/risk of bullying, abuse, and abandonment in clinical finding hierarchy.
      • Inactivation of 112625008|Cutaneous eruption (morphologic abnormality) in favor of using 1806006|Eruption (morphologic abnormality)| relationship grouped with a finding site, approximately 51 concepts remodeled.
      • Remodeling of joint temperature-related concepts: adding parents, interprets values and sufficiently defining where appropriate.

Convergent Medical Terminologies (CMT)

New CMT concepts: 702

The majority of these newly authored concepts are in scope for mapping to ICD-10 and from the following domains:

        • CMT Ophthalmology - 285
        • CMT Mixed Domains - 410
        • CMT Musculoskeletal - 7

Procedure Hierarchy

New concepts for procedure hierarchy: 215

    • Diagnostic imaging - 72 requests were received for new imaging procedure concepts with various imaging modalities.
        • Plain X-ray 63 new concepts.
        • Magnetic resonance imaging 3 new concepts.
        • Ultrasound 5 new concepts.
        • Computed tomography 1 new concept.

    • Addition of 6 laparascopic pectopexy concepts.

    • Colorectal excision -changes have been made in either modeling, description, or addition of over ten procedure hierarchy concepts concerning the excision/resection of colon and/or rectum, anal anastomosis, colostomy, and/or creation of intestinal pouch.  

    • 121278003 |Drug measurement (procedure)| has been inactivated for the 2019-July Release and descendant concepts have been updated accordingly (n≈150). Because exposure to the substance being measured may or may not be due to the substance being used in a medicinal product, the grouper was inactivated as Ambiguous with Possibly equivalent to relationship to 430925007 |Measurement of substance (procedure)|.

    • 80 descendants of 784396007 |Graft of skin to skin (procedure)| were remodelled to fix issues identified in the previous 304040003|Skin grafting| sub-hierarchy. A consistent modelling plan with one role group was adopted and the FSN and PT terming pattern adapted to match "[skin graft material substance] to [skin structure]." Skin graft procedure concepts were updated and now use the same terming throughout. Subsumptions that were expected but previously did not exist have been achieved through the development of a sub-hierarchy 420934007 Graft of skin (substance) and 32 descendants specifically for use in these procedures. A Template is currently under development.

    • Created new and remodelled Implantation and Insertion qualifier values and procedures:
      • Inactivated: 71861002 |Implantation (procedure)| - replaced with new 782902008 |Implantation procedure (procedure)|; Retained as subtype of introduction for use with non-biological devices.
      • Created new concept: 770651008 |Insertion procedure (procedure)|
      • Reactivated 129336009 |Implantation - action (qualifier value)| as subtype of 424832003 |Surgical introduction - action (qualifier value)
      • Made 129337000 |Re-implantation - action (qualifier value)| a subtype
      • Made 129407005 |Grafting - action (qualifier value)| a subtype
      • Made 129406001 |Transplantation - action (qualifier value)| a subtype

Collaboration/Harmonization Projects


As a result of collaboration with Orphanet ( 306 new SNOMED CT concepts have been created to represent rare diseases in the disorder hierarchy. All of these concepts have been mapped to ICD-10. 

Global Medical Device Nomenclature Agency (GMDNA)

55 new SNOMED CT concepts created and mapped in the Physical object hierarchy to support the GMDN collaboration agreement.


New concepts added: 27

Work continued on the following Content Projects:

        • IHTSDO-1071 - Continued inactivation of transport accidents; movement of all vehicle accidents to children of Transport accidents; Fully-defining some when possible and adding additional parents if appropriate.

Record Artifact

New concepts added: 61

54 new concepts added for care plan.


New organism concepts added: 326

Content quality improvements:

        • 268 New concepts (Including 117 Shiga toxin producing E coli concepts) and 12 changes to the existing concepts' descriptions.
        • Inactivation of 21 ambiguous concepts across multiple hierarchies which had included an animal species when referring to an Influenza virus (e.g., Myocarditis caused by avian influenza (disorder), Influenzavirus type A, avian, H5N1 strain (organism)). 6 new concepts were created in this process.
        • Correction of Influenza virus descriptions: Around 350 corrections/changes were made to Influenza virus descriptions over multiple hierarchies (majority in substance hierarchy but also including disorder, procedure and organism hierarchies). Most of the changes consisted of inactivation of the erroneous description and replacement with a new correct description. In addition, two new concepts were added in the organism hierarchy.
        • Application of consistent case sensitivity to organism descriptions containing "Taxon Rank": Change of the case sensitivity setting for 10282 descriptions (over 4964 concepts).
        • Concepts with descriptions that include the word 'unclassified' were inactivated (7 concepts).
        • Duplicate descriptions were identified and corrected for 11 Concepts.
        • Spelling errors were corrected for 29 concepts.
        • Historical associations were corrected for 32 concepts.

Pharmaceutical / biologic product

Drug model project

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 2019-July International Release.

Clinical drug (CD) concepts
  • PTs updated and synonyms matching FSN removed for existing concepts (n≈4900) in accordance with Editorial Guidelines

  • Inactivated CDs that were modeled with both concentration and presentation strength; replaced with concepts containing concentration strength only (inactivated concepts n≈575; new concentration-only concepts n≈400)

  • Relocated CDs that have not been sufficiently defined to be descendants of 770654000 |TEMPORARY parent for CDs that are not updated (product)|; these concepts will be sufficiently defined or inactivated in future release (n≈2700)
    • Concepts that were not able to be mapped to dm+d but can be mapped to an RxNorm concept will be retained as primitive for the 2019-July Release in the existing location as descendants of 770654000 | TEMPORARY parent for CDs that are not updated (product). These concepts will be sufficiently defined and remodeled in a future release. (n≈1800)
    • Concepts that cannot be mapped to either dm+d or RxNorm concept will be retained as primitive for the 2019-July Release in the existing location as descendants of 770654000 | TEMPORARY parent for CDs that are not updated (product). These concepts will be addressed in a future release. (n≈900)
  • Editorial Guidelines updated, including diagrams showing self-grouped attributes

  • Updated Member Forum Briefing Note - Implications of describing liquid dose form product concepts using presentation strength

Demo release

  • Demo release distributed in 2018-Sep included the following for Medicinal product hierarchy:

    • Updated terming per Ed Guide for existing concepts
    • MP-only (near complete set of concepts to be included in 2019-Jan Release)
    • MPF-only (near complete set of concepts to be included in 2019-Jan Release)
    • Role (subset of content to be included in 2019-Jan Release)

Groupers based on disposition and/or structure
  • Change semantic tag from (product) to (medicinal product) and updated terming for chemical element groupers (n≈30) in accordance with Editorial Guidelines

  • Added new disposition groupers (n≈25)

  • Added new structural groupers (n≈10)

  • Editorial Guidelines updated for disposition, structure, and dose form intended site groupers

  • PTs updated and synonyms matching FSN removed for existing concepts (n≈500) in accordance with Editorial Guidelines
Liposome modifications
  • Create MP-only and MPF-only concepts for liposome products

  • Editorial Guidelines updated to identify these concepts as exceptions to the modification guideline
Medicinal product "containing" (MP-containing) concepts
  • Editorial Guidelines updated, including diagrams showing self-grouped attributes

  • PTs updated and synonyms matching FSN removed for existing concepts (n≈3800) in accordance with Editorial Guidelines
Medicinal product "only" (MP-only) concepts
  • Editorial Guidelines created, including diagrams showing self-grouped attributes

  • Initial deployment of MP-only concepts (n≈3800)
Medicinal product form "containing" (MPF-containing) concepts
  • Editorial Guidelines updated, including diagrams showing self-grouped attributes

  • PTs updated and synonyms matching FSN removed for existing concepts (n≈2800) in accordance with Editorial Guidelines
Medicinal product form "only" (MPF-only) concepts
  • Editorial Guidelines created, including diagrams showing self-grouped attributes

  • Initial deployment of MPF-only concepts (n≈2800)
National Extension model
  • New top level concept added (for use by national extension model but not for International Release)
    • 781405001 |Medicinal product package (product)|

  • New semantic tags added (for use by national extension model but not for International Release)
    • (product name)
    • (packaged clinical drug)
    • (real clinical drug)
    • (real medicinal product)
    • (real packaged clinical drug)
    • (supplier)

  • New attributes added (for use by national extension model but not for International Release)
    • 774158006 |Has product name (attribute)|
    • 774159003 |Has supplier (attribute)|
    • 774160008 |Contains clinical drug (attribute)|
    • 774161007 |Has pack size (attribute)|
    • 774163005 |Has pack size unit (attribute)|

  • New hierarchies added (for use by national extension model but not for International Release)
    • 774164004 |Supplier (supplier)|
    • 774167006 |Product name (product name)|

  • Editorial Guidelines created
  • Created new 773830008 |Consumer product (product)| hierarchy as sibling of 763158003 |Medicinal product (product)|. Relocated descendants of 763087004 |Medicinal product categorized by therapeutic role (product)| as appropriate (e.g. Aftershave, Deodorant, Perfume) (n≈25)

  • Inactivated role concepts representing body site or body system (e.g. Gastrointestinal drug, Genitourinary drug) (n≈15)

  • Relocated 43747001 |Drug excipient (product)| as sibling of 763158003 |Medicinal product (product)|. Relocated descendants of 763087004 |Medicinal product categorized by therapeutic role (product)| as appropriate (e.g. Drug additive, Drug flavoring) (n≈15)

  • Created descendants of 766941000 |Therapeutic role (role)| (n≈80) and remodeled corresponding descendants of 763087004 |Medicinal product categorized by therapeutic role (product)| (n≈80)

  • Populated the following roles:
    • 43927002 |Medicinal product acting as analeptic agent (product)| (additional axiom n≈5)
    • 81839001 |Medicinal product acting as anticoagulant (product)| (additional axiom n≈25)
    • 358926001 |Medicinal product acting as antidementia agent (product)| (additional axiom n≈10)
    • 386757008 |Medicinal product acting as antiglaucoma agent (product)| (additional axiom n≈20)
    • 781514009 |Medicinal product acting as antixerostomia agent (product)| (additional axion n≈5)
    • 96326006 |Medicinal product acting as ceruminolytic agent (product)| (additional axiom n≈5)
    • 15117003 |Medicinal product acting as hemostatic (product)| (additional axiom n≈30)
    • 61621000 |Medicinal product acting as laxative (product)| (additional axiom n≈120)

 Veterinary Extension

10 concepts were moved to the Veterinary Extension. 

Situation with Explicit Context

New concepts added : 50

32 new concepts were added for 'X disease suspected.'

Additions and improvements in areas of suspected/risk of bullying, abuse, and abandonment in situation hierarchy.

22 situation concept FSNs updated in areas of organism examination and samples sent.

Observable Entity

56 new concepts were added.

5 laboratory observable entity concepts added based on request by two member countries; 2 observable entity concepts added in a non-laboratory area.

1 observable entity laboratory concept inactivated.

Assessment Scale

Addition of 11 new assessment scale concepts.


223 new concepts were added.

Case Sensitivity changes:

Improvement of  substance concepts by updating case sensitivity based on editorial guidelines in the following areas - 5000 concepts.

    • Greek alphabetical terms in substance concepts have been made case insensitive.
    • Single word substances incorrectly marked case sensitive have been amended.
    • For substance terms that have a single letter - either a single lower case letter or a single upper case letter - the case sensitivity has been changed so now correctly reflects this.
    • Substance terms containing proper names now reflect this capitalization requirement, and quality checks have been performed on the substance hierarchy based on the file used for automated spell-checking and automated case sensitivity checking. A decision was taken to make the substance hierarchy the 'source of truth' for other hierarchies within SNOMED CT.
    • Rule established that numbers at the beginning of substance terms can be ignored for case significance, and the case sensitivity assignment now starts with the first letter, including batch amendment of incorrect capitalization in terms that include numbers.

Changes in the substance hierarchy as the result of Allergy project requirements:

    • Inactivate top level groupers/Allergen classes in substance hierarchy by reassigning their children to appropriate structural and/or functional parents.
      • 414052000 | Drug allergen by structure | 
      • 414058001 | Drug pseudoallergen by function | 
      • 414057006 | Drug pseudoallergen |
      • 414053005 | Drug allergen or pseudoallergen |

Changes to language acceptability

  • Primarily, but not limited to, Substance terms used in the Products hierarchy, the Preferred Term in the US dialect has been made Acceptable in the GB dialect and vice versa.
  • Also work completed on the removal of some dialect variations (643 concepts): 
    • Acceptability change of the Preferred Term (PT) in US dialect changing from Not acceptable to Acceptable as a GB synonym, and vice versa (GB PT made Acceptable as a synonym in US dialect previously Not acceptable) - 422 concepts.
    • Removed a dialect variation and now the concepts have a single PT that covers both dialects - 221 concepts.

Other content quality improvements:

    • Added/updated “Is modification” attribute where applicable - 630 concepts.
    • Added/updated modeling for existing concepts by adding "has disposition" attribute where applicable - 540 concepts.
    • Added new disposition to model for existing content - 41 concepts.
    • Added new structural grouper concepts to model for existing content - 61 concepts.
    • Update of model for existing concepts by adding missing structural parent(s) - 1500 concepts.
    • Improvement of substance concepts by aligning them to the International Nonproprietary Name (INN) - 380 concepts.
    • Improvement of substance concepts by removing symbols like "[" in substance terms - 30 concepts.
    • Spelling changes - 25 concepts.
    • Missing historical associations found for 4 concepts and issue was resolved.

Release plans, Substance hierarchy

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.

Internal Quality Improvement

Logic Profile Enhancements

Release of partial OWL expression refset

Content updates in the OWL axiom refset:

    • 185 new additional axioms for product roles.
    • 20 new General Concept Inclusion (GCI) axioms.
    • 1 new property axiom for "Proper part of".
    • 1 inactivation of property axiom for "Part of".

A set of documentation has been developed to support the Logic Profile Enhancements: 

Machine Readable Concept Model (MRCM)

6 new MRCM rules and 3 updates to the existing MRCM in the MRCM refsets and authoring platform were made for the July 2019 release:

    • New MRCM for the new attribute 774081006 |Proper part of|
    • New MRCM for new attribute 774160008 |Contains clinical drug (attribute)|
    • New MRCM for new attribute 774161007 |Has pack size (attribute)|
    • New MRCM for new attribute 774163005 |Has pack size unit (attribute)|
    • New MRCM for new attribute 774159003 |Has supplier (attribute)|
    • New MRCM for new attribute 774158006 |Has product name (attribute)|
    • Inactivate MRCM for 363705008|Has definitional manifestation (attribute)|
    • Inactivate MRCM for 123005000 |Part of|
    • Expand the range of 370135005 |Pathological process (attribute)| to include << 769247005 |Abnormal immune process (qualifier value)|

The further details can be found here

Definition Status

Improvements have been made to fully specified names and synonyms to clarify the intended meaning of the existing concepts for definition status. The decision to retain the existing concepts with improved descriptions was made to reduce disruption to users, though the definition status has limited logical value in SNOMED CT since the addition of the OWL Axiom Refset. The revised descriptions are consistent with the advice provided by the majority of SNOMED Modeling Advisory Group members.

The descriptions for the definition status with concept id 900000000000073002 are now:

  • FSN: Sufficiently defined by necessary conditions definition status (core metadata concept)
  • SYN (Preferred): Defined
  • SYN (Acceptable): Sufficiently defined by necessary conditions definition status

The new fully specified name reflects that concepts with this definition status must have a set of necessary relationships that are sufficient to define the concept.

The descriptions for the definition status with concept id 900000000000074008 are now:

  • FSN: Not sufficiently defined by necessary conditions definition status (core metadata concept)
  • SYN (Preferred): Primitive
  • SYN (Acceptable): Not sufficiently defined by necessary conditions definition status

The new fully specified name reflects that concepts with this definition status do not have a set of necessary relationships that are sufficient to define the concept. 

Potential impact:

  • The structural subsumption technique, based on definition status and inferred relationships, should not be used to test subsumption between SNOMED CT Expressions. This is because sufficient but not necessary relationships and other DL enhancements are not represented in the inferred relationship file. Accurate expression subsumption now requires use of the OWL refsets and a DL classifier.
  • The colors and shapes used to represent concept model diagrams should follow the assigned or derived definition status.
  • Some updates will be required to documentation and education materials.

SNOMED CT derived products

 ICD-10 map

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)|.

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. As part of the ongoing quality improvement of the published maps  SNOMED CT concepts mapped to code range Q90 - Q99 Chromosomal abnormalities, not elsewhere classified  have been reviewed and the previously assigned map advice POSSIBLE REQUIREMENT FOR AN EXTERNAL CAUSE CODE has been removed for consistency purposes.

 Mapped content for July 2019

The map provided for the July 2019  release has been updated, and now represents a complete map from SNOMED CT International release to ICD-10 2016 version.

    • 2321 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

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:


       There are 5 updates for the ICD-O Morphological abnormality map in July 2019 release. 

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:

Please contact SNOMED International at if you would like to provide any feedback on ways to extend and improve the new toolkit.

3 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 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):

Key Summary Description

 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 - 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:

Key Summary Description Resolved

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

  1. ...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 
  2. ...files that just 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.

Combination of two new refsets - OWLAxiom and OWLOntology

Please see section "2.3.1 Logic Profile Enhancements" above for full details of the reason behind the introduction of these new refsets.  After the September 2018 Demonstration release, it was agreed to combine these two files into one "OWL Expression" file, which now contains both OWL Axiom + OWL Ontology refsets in the same file, in each section of the International Release package (Full, Snapshot and Delta):

  • sct2_sRefset_OWLExpressionFull_INT_20190131.txt
  • sct2_sRefset_OWLExpressionSnapshot_INT_20190131.txt
  • sct2_sRefset_OWLExpressionDelta_INT_20190131.txt

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 (in July 2019), and therefore contain core content which needs to be included in the Terminology folder.

Replacement of OWL conversion script with a link to the open source directory

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):

Please contact SNOMED International at if you would like to provide any feedback on ways to extend and improve the new toolkit.

Deprecation of the Technical Guide Exemplars document from the International Edition release package

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 above for the relevant link.

Early visibility of impending change in the July 2019 International edition

Please see the following page for details of all upcoming changes planned for July 2019 and beyond:  Early Visibility - Planned changes to upcoming SNOMED International Release packages

IMPORTANT CHANGE in the July 2019 International Edition

Replacement of the Stated Relationship files with the new OWL Axiom refset files

In the July 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 July 2019.  Please contact SNOMED International at 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:


Final Version




0.120190131 ALPHA VersionLesley MacNeilApproved with revsions in blue
June 5, 2018Maria BraithwaiteApproved
June 5, 2018Donna MorganApproved
0.1June 5, 2018Jim Case/Paul AmosApproved

July 31, 2018

Rory DavidsonApproved

July 3, 2018

Maria BraithwaiteApproved

 July 3, 2018

Lesley MacNeilApproved

Draft Amendment History







Andrew Atkinson

First draft for review and comment


20180619Maria Braithwaite / Andrew AtkinsonFinal updates, including map record count update


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