Introduction

Background

SNOMED CT terminology provides a common language that enables a consistent way of indexing, storing, retrieving, and aggregating clinical data across specialties and sites of care.

SNOMED International maintains the SNOMED CT technical design, the content architecture, the SNOMED CT content (includes the concepts table, the descriptions table, the relationships table, a history table, and ICD mappings), and related technical documentation.

Purpose

This document provides a summarized description of the content changes included in the July 2020 additional Rollup Delta package 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 additional Rollup Delta package.

Scope

This document is written for the purpose described above and is not intended to provide details of the technical specifications for SNOMED CT or encompass every change made during the release.

Audience

The audience includes National Release Centers, WHO-FIC release centers, vendors of electronic health records, terminology developers and managers who wish to have an understanding of changes that have been incorporated into the July 2020 International Edition additional Rollup Delta package.  Those users who have downloaded and used the March 2020 Interim International Edition in their systems do not need to use this additional Rollup Delta package.

Format of this package

This package contains content in the DELTA files only - the Full and Snapshot files are all intentionally empty.  This is to prevent any confusion with the official, published International Edition Full and Snapshot files.

The Delta files contain all changes from the March 2020 Interim International Edition release plus the July 2020 International Edition release, with the original effectiveTimes as released in the published International Edition files.

Utilisation of this package

For those users who did NOT use the March 2020 Interim International Edition release in their systems, the advise on getting 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 this July 2020 International Edition additional Rollup Delta package.
   1. If you use this package, then please be aware of the multiple effectiveTimes (per ComponentID) in the Delta files.   For example if a concept has been added in March 2020, and then inactivated in July 2020, both 20200309 activation record + 20200731 inactivation record will exist in the same Delta file for this rollup period.
   2. This is not an issue from an RF2 perspective, it simply needs to be accounted for in any upload or import routines used to consume the July 2020 International Edition additional Rollup Delta package.
      
      
3. Please take notice of (and use where required) the new machine readable .JSON metadata file included in the Rollup Delta package.  This will delineate the difference between the fact that the July 2020 release has Delta files relative to the March 2020 release, whereas this Delta Rollup package has Delta files relative all the way back to the January 2020 release (see details in the Technical Notes section below)

Content Development Activity

The July 2020 International Edition additional Rollup Delta package includes ALL changes (in DELTA files only) published across all packages released since January 2020, with the actual, official effectiveTime as at the time of publication.  In this particular case, this includes both the March 2020 Interim International Edition release, plus the July 2020 International Edition release.

Therefore, for example, all of the new Coronavirus content (from the March 2020 Interim International Release) would have an effectiveTime of 20200309, whilst the remainder of the content will have an effectiveTime of 20200731 as it will comprise changes from the July 2020 International Edition release.

Technical notes

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.

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.  

In this case the .JSON file will also be included, and will show the difference between the fact that the July 2020 release has Delta files relative to the March 2020 release, whereas this Delta Rollup package has Delta files relative all the way back to the January 2020 release.  This will be seen in the "DeltaFromDate" field, which will be equal to 20200309 in the July 2020 release, but in this Delta Rollup package will be equal to 20200131, clearly stating that this Delta Rollup package includes ALL changes since the January 2020 International Edition release, and not just those changes since the March 2020 release.

1. In this context the file will show the following for the official July 2020 release, as the Delta files in this package are relative to the previously published March 2020 release:
   

   1. effectiveTime     "20200731"

   2. deltaFromDate   "20200309"

   3. deltaToDate        "20200731"
      
2. Whereas the same metadata file will show the following for the July 2020 Rollup Delta release, as the Delta files in this package are relative to the previously published January 2020 release:
   

   1. effectiveTime     "20200731"

   2. deltaFromDate   "20200131"

   3. deltaToDate        "20200731"

Release Notes naming convention

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

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

   Instead of the previous underscore after "Current":

• • doc_SnomedCTReleaseNotes_Current_en-US_INT_[date].pdf

Document links

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