Introduction

Health New Zealand - Te Whatu Ora works with health agencies and their industry partners to develop SNOMED CT® reference sets, maps, language reference sets and other content for digital health solutions in Aotearoa New Zealand.

The SNOMED CT New Zealand Extension packages these components for release every April and October, to be used with the latest designated SNOMED CT International Edition release.

The content can be downloaded from our member licensing and distribution service, viewed online using the SNOMED CT browser or accessed via a standard FHIR® API using the NZ Health Terminology Service. 

We welcome your feedback and participation. For more information about SNOMED CT implementation in New Zealand, email standards@health.govt.nz, see our website or join our standards channel at ehealthforum.nz.

Background

This document provides a summarized description of the content changes included in the April 2024 production release of the SNOMED NZ Extension package.

It also includes technical notes detailing any known issues.

This SNOMED NZ Extension package is dependent upon and should therefore be consumed in conjunction with the SNOMED CT International Edition February 2024 release.

Content development activity

Summary

Content from the SNOMED CT International Edition February 2024 release has been incremented, using additional components for use in New Zealand. 

The April 2024 release includes updates to the previously released content in the SNOMED NZ Extension and introduces some new content.

This release includes new content in the following areas.

Common route of administration reference set 

The April 2024 release of the SNOMED NZ Edition adds a common route of administration reference set to support coded medicines information in community prescription and dispensing records for the NZ ePrescription Service (NZePS), Medicines Data Repository and all patient records.

• 361531000210107 New Zealand common route of administration reference set

CanShare reference sets

Te Aho o Te Kahu (Cancer Control Agency) has developed a collection of 509 CanShare reference sets for Aotearoa. These reference sets provide standard sets of SNOMED CT concepts to use for recording, sharing and querying cancer data. Each concept in these reference sets has a preferred term in the CanShare language reference set (SCTID 231621000210105), selected by New Zealand clinicians to standardise the way that cancer data is displayed across Aotearoa. These reference sets are designed to support a range of cancer data, including histology, topography, grading, staging, scoring, treatment intents, disease response, cancer streams, and primary cancer types. 

The April 2024 release includes 231 new CanShare reference sets, 203 updated reference sets, and 477 new concepts in the following areas:

• Cancer streams, substreams and primary cancer types to support clinical workflows.
• Topographies for recording the primary site of a cancer. This includes a maximal set of body sites, a high-level set of commonly used body sites, and body sites specific to landmarks (new), lymph nodes (new), and tumours of the thorax, breast, gastrointestinal tract (new), female genital sites (new) and genitourinary sites (new).
• Cancer histologies for haematolymphoid, breast, thoracic, female genital, digestive, genitourinary, and soft tissue & bone (new), based on the WHO Classification of Tumours 5th edition.
• Grading systems for haematolymphoid, breast, female genital (new), and other(new) cancers.
• Staging systems for haematolymphoid, breast, thoracic, female genital (new), gastrointestinal (new) and neuroendocrine (new) cancers, including clinical, pathological, recurrence or retreatment, and post therapy or post neoadjuvant therapy staging.
• Prognostic scoring systems for haematolymphoid and female genital (new) cancers.
• Neoadjuvant therapy response scoring systems for colorectal (new) and breast (new) cancers
• Specimen collection procedures to support all cancer types (new), including colorectal cancers (new).
• Additional data to support systemic anti-cancer therapy treatment plans, including basis of diagnosis, treatment intent, disease response, dose forms, dose units, and ancillary studies for breast tumours.

New and updated content

Concept statistics

The SNOMED NZ National Release Centre promoted 17 new concepts to the SNOMED CT International Edition February 2024 release.

Table 1. New concepts in the SNOMED International February 2024 release by hierarchy

There are 567new concepts in our April 2024 release.

Table 2. New concepts in the SNOMED NZ Extension April 2024 release by hierarchy

Description statistics 

There are 985 new descriptions added to our April 2024 release.

For a statistical breakdown of the content of the SNOMED NZ Extension and the April 2024 release please visit release statistics site.

Reference sets

There are 581 reference sets in the April 2024 release including 232 new reference sets. 

For more information about New Zealand reference sets, please visit our website.

Language reference sets

Language reference sets are created to define preferred terms and synonyms associated with each concept. There are four language reference sets in the April 2024 release.

Maps

Five maps between SNOMED CT and other code systems are contained in the April 2024 release.

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.  

The following known issues were identified, and agreed to be resolved in the next editing cycle:

Notice of changes to the International Edition release schedule

The SNOMED CT International Edition has moved to a monthly release cycle. These more frequent releases of SNOMED CT will realize several benefits, including:

• The potential to be able to get content changes into the terminology in a shorter time frame.
• The fostering of better interoperability, as a result of entities being able to consume release content that is more aligned with other organizations.
• The prevention of circular dependencies that occur in longer projects, due to the move towards smaller, more manageable authoring projects.
• More automated validation services, as a result of the inherent removal of the Alpha/Beta stages in the Release cycle.

Whilst most users will continue unaffected (as they can simply continue to download the releases every 6 months as always), this transition will necessarily involve a few changes to process/packages:

• Delta files have been removed from releases of the SNOMED CT International Edition and SNOMED NZ Extension. A Delta Generation service will be provided for those who need it. The Delta Generation Tool allows users to create their own Delta between two fixed release dates - you can find it here:
  • https://github.com/IHTSDO/delta-generator-tool/releases

• The ICD-O/ICD-10 Maps will continue to be published in each Monthly International Edition release package (in line with that month's content) for the foreseeable future, unless we experience issues with the new process in Production, and they need to be removed at a later date.

The first monthly Release of the SNOMED CT International Edition was published on the 28th February 2022 with the Delta files having been removed, and therefore they will be removed from the New Zealand Extension from the April 2022 Release onwards.

Please note - While the SNOMED CT International Edition is moving to monthly releases, the New Zealand Extension of SNOMED CT will remain on the current bi-annual release schedule of April and October for 2023.

Changes to the Identifier file format

In line with the proposals documented here:  https://confluence.ihtsdotools.org/mag/snomed-international-proposal-to-change-the-rf2-identifier-file-specification - the New Zealand Extension Release will from now on include the following changes to the format of the Identifier files:

• < identifierSchemeId    alternateIdentifier    effectiveTime    active    moduleId    referencedComponentId           ...to
• > alternateIdentifier    effectiveTime    active    moduleId    identifierSchemeId    referencedComponentId

These improvements are introduced in the October 2023 New Zealand Extension release, and will be used in all future New Zealand Extension releases until further notice.

Notice of changes to the NZ Extension Release package

In line with the new implementation of Annotations, two new refsets have been added to the International Edition Release package, from December 2023 onwards:

• • der2_scsRefset_ComponentAnnotationStringValueSnapshot_INT_20231201.txt
  • der2_sscsRefset_MemberAnnotationStringValueSnapshot_INT_20231201.txt

The latest version of the NZ Extension release is based upon the February 2024 International Edition, and therefore these Annotations file types will also be included in the NZ Extension release package from the April 2024 NZ release onwards, until further notice:

• • der2_scsRefset_ComponentAnnotationStringValueFull_NZ1000210_20240401.txt
    
  • der2_scsRefset_ComponentAnnotationStringValueSnapshot_NZ1000210_20240401.txt
    
  • der2_sscsRefset_MemberAnnotationStringValueFull_NZ1000210_20240401.txt
    
  • der2_sscsRefset_MemberAnnotationStringValueSnapshot_NZ1000210_20240401.txt

These refset files are empty for the April 2024 NZ Extension release, whilst content is being authored for future editing cycles. 

Notice of changes to the NZ Extension Release package

The New Zealand NRC has decided to extend the standard International DescriptionType specification, which currently restricts Description term lengths to 255 characters.  The New Zealand extension, from the April 2024 onwards, now specifies term lengths can be created up to 4096 characters.  

This means that users wanting to utilise New Zealand Extension Descriptions, should use the specialised New Zealand DescriptionType.