Introduction

The 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. The International Health Terminology Standards Development Organisation (IHTSDO^®) maintains the SNOMED CT technical design, the content architecture, the SNOMED CT content (including the concepts table, the descriptions table, the relationships table, a history table and ICD mappings), and related technical documentation. 

The DEMO release package is distributed for evaluation purposes only.  It must not be used in production clinical systems or in clinical settings. 

Audience for this document

This document should be read by all those who will be reviewing or submitting questions or comments related to the DEMO Release, including participation in any follow up meetings. 

Scope and Purpose

The complete OWL axiom reference set has been developed to replace the stated relationship file following the first release of a partial OWL axiom reference set in the July 2018 International Edition. In this demonstration release, the OWL axiom reference set represents all stated relationships including all new description logic features, such as general concept inclusion (GCI) axioms and additional axioms. The purpose is to provide an early view to help our community to evaluate their tooling, systems and release process.  Please note that the content modeling is still a work-in-progress and these examples are being provided for demonstration purposes only and are not necessarily reflective of content that will be in the January 2019 or July 2019 Releases.

Release content

Content detail

Therapeutic role modeling

• As previously communicated, therapeutic roles associated with concepts in the 763158003 |Medicinal product (product)| will be modeled using additional axioms beginning in the 2019-January Release. 
• For examples of therapeutic role remodeling using the new attribute 766939001 |Plays role (attribute)|, see descendants of:
  • 763087004 |Medicinal product categorized by therapeutic role (product)|
  • 386757008 |Medicinal product acting as antiglaucoma agent (product)|
  • 96326006 |Medicinal product acting as ceruminolytic agent (product)|
  • 61621000 |Medicinal product acting as laxative (product)|
• Medicinal product containing only and Medicinal product form containing only concepts have been added; concepts are sufficiently defined and modeled to proximal primitive

Remodeling of hypersensitive conditions

The new concept model for hypersensitive conditions has been approved for implementation. Hypersensitivity condition is a direct descendant of clinical finding. Allergic and Nonallergic hypersensitivity (pseudoallergic) condition both of which are primitive each have three main sub-hierarchies representing diseases (mostly abnormal structures), processes (allergic and nonallergic hypersensitivity (pseudoallergic) reactions) and findings of propensities to developing allergic and nonallergic hypersensitivity (pseudoallergic) reactions (dispositions).

Hypersensitive condition and allergic condition are modelled by four general concept inclusion axioms. The relationships in the GCIs are sufficient conditions and are excluded from the inferred relationships. The concept model for allergic disposition and allergy concepts with semantic tag (finding) have been updated in the demonstration release. These concepts would not be classified under the allergic condition (finding) without the GCIs. 

Release content

Detailed documentation regarding changes to the Substance and Drug hierarchies that are in scope to be reviewed for this DEMO release are located on the project Confluence sites:

• Drugs Section 3 of Early Visibility July 2019 Release - Planned changes to upcoming SNOMED International Release packages
• Substances Section 4 of Early Visibility July 2019 Release - Planned changes to upcoming SNOMED International Release packages

Please note that comments and questions submitted related to content not specifically identified as in scope for this DEMO release will be rejected.

Effective date

The Demo release will be made available for your review with an effectiveTime of 20180921 20190131 and close on 0501-OCTMarch.

Technical Notes

RF2 package format

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.

Release of OWL reference sets

As an essential part of SNOMED CT Logic Profile Enhancements, the OWL refsets have been developed to represent logic definitions following the international standard of OWL 2 Web Ontology Language. In the 2018 July releasereleases of International Edition in July 2018 and January 2019, the scope for the content in the OWL axiom refset is limited to property chains, transitive properties, and reflexive properties.In this Demo release, the , the general concept inclusion (GCI) axioms and additional axioms that are implemented to support the Drug, Anatomy content projects. 

In this Demo release, the complete OWL expression refset has been developed. In addition to those axioms in the partial OWL axiom refset, all and implementation of the new concept model for hypersensitivity conditions. All active relationships in the stated relationship file have been transformed into the OWL axiom refset. Therefore, the OWL axiom refset represent represents all logical definitions for the entire SNOMED CT International release.There are no changes to the content in the OWL ontology refsetEdition. The files for OWL axiom refset and OWL ontology refset are merged into a single file called OWL expression refset in the January 2019 release.

The OWL Reference sets are expression refset is placed under the Terminology folder in the release file package.

• der2xsct2_sRefset_OWLOntology_DeltaOWLExpressionSnapshot_INT_20180914.txt
• der2_sRefset_OWLAxiom_Delta_INT_20180914.txt
• 20190131

The complete OWL expression The complete OWL axiom refset in this Demonstration release will be available on request in the January 2019 release. The complete OWL axiom refset will be mandatory from the July 2019 release.

Stated relationship file

The stated relationship file will be deprecated after the January 2019 release. As noted in the July 2018 release, the stated relationship file is no longer the complete representation of all logical definitions. The partial OWL axiom refset must be used for description logic classification.

In this Demo release package, all entries are inactivated in the stated relationship file. The purpose is to avoid duplications to the completed OWL axiom refset for preview. We encourage users to utilise this Demo release for evaluating their tooling, systems and release process.

Following the feedback, the normal stated relationship file will still be available in the January 2019 release package and the partial OWL axiom refset will include all description logic features that cannot be represented in the stated relationship file.

Inferred relationship file

The inferred relationship file will maintain the same format and structure, and it is no longer an equivalent to the stated form (containing all necessary and sufficient conditions). It is a collection of all the necessary conditions and represents a subset of the full semantics.

The rules for generating the relationship file are included in the document SNOMED CT OWL Guide. The examples in the document can be used as testing cases for the tooling and systems to produce consistent inferred relationships.

Improvement for the representation of role groups

It is important to clearly indicate if an attribute is grouped or not because role group has impact to semantics and classification results. The majority members of the Modeling Advisory Group recommended explicit representation for role groups. There will be two key improvements for the representation in the July 2019 release. The changes are demonstrated in this release package.

Firstly, role groups are explicitly stated and represented by the concept 609096000|Role group (attribute)| as an object property in the OWL axiom refset.

Secondly, for inferred relationship file, role group 0 will be only applied to attributes that are not logically grouped, e.g. not a value of 609096000|Role group (attribute)| in an OWL axiom or grouped = 0 in the MRCM. This addresses the potential confusion whether an attribute is grouped or not in the role group 0. 

The improvements will provide consistent representation for role groups in the OWL axioms, inferred relationship file, and diagramming of concept model. 

A set of documentations have been developed to support the Logic Profile Enhancements. Please see the detail in the following links.

Documentations

SNOMED CT OWL Guide

SNOMED CT Logic Profile Specification

SNOMED CT Logic Profile Enhancements