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@healthnz.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 October 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 August 2024 release.

Content development activity

Summary

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

The October 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.

NZ Breast Device Registry (NZBDR)

A set of SNOMED concepts has been developed to support the New Zealand Breast Device Registry (NZBDR) | Te Rehita Taputapu Uma o Aotearoa.

The purpose of the NZBDR is to provide medical information, reporting, device tracking and auditing for complications for the women of New Zealand and their health professionals. The registry makes it possible to trace patients in the event of a product recall or safety concern related to a specific type of implant.

NZBDR holds a clinical record for all surgically implanted devices including breast prostheses, tissue expanders and alloplastic and biological meshes. It also records all associated surgical procedures including both primary and secondary (revision procedures), the indications for those procedures and all complications.

Health service type reference set

This reference set has been updated in partnership with Healthpoint to further adapt the healthcare services hierarchy to reflect the health system in Aotearoa New Zealand.

Patient friendly terms, selected by Healthpoint, have been included in the SNOMED CT New Zealand edition along with te reo Māori equivalent terms developed by Te Taura Whiri i te Reo Māori | Māori Language Commission accredited translators.

Health occupation reference set

The reference set has been updated in response to a number of requests to add occupation codes relevant to the New Zealand health sector.

Emergency care reference sets

The chief presenting complaint and diagnosis reference sets have been updated out of the six-monthly clinical review cycle.

Systemic Anti-Cancer Therapy Regimen Library

Lists of SNOMED concepts are created to support the ACT-NOW programme to develop a detailed database of information on patients receiving systemic anti-cancer therapy across New Zealand.

MSD translation table map

Updated to include 37 additional rows to meet MSD requirements. 

READ v2 to SNOMED CT map

Updated to improve mappings for smoking-related codes. Following are the approved smoking-related mappings. See also Recording smoking status | Ministry of Health NZ.

Other changes

Eighteen reference sets have been updated to replace inactive concepts with the active concepts.

CanShare reference sets

Te Aho o Te Kahu | Cancer Control Agency has developed a collection of 605 CanShare reference sets for Aotearoa New Zealand. These reference sets provide standard sets of SNOMED concepts to use for recording, sharing and querying cancer data in Aotearoa. Each concept in these reference sets has a preferred term in the CanShare language reference set, 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, prognostic and neoadjuvant scoring, treatment intent, disease response, cancer streams, and primary cancer types.

The October 2024 release of the SNOMED NZ Edition includes 184 new CanShare reference sets, 137 updated reference sets, 284 static reference sets, and 1,965 new concepts to support these in the following areas:

• Cancer streams, substreams and primary cancer types to support clinical workflows for medical oncology and haematology.
• 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 breast, thoracic, gastrointestinal, female genital, genitourinary, soft tissue & bone (new), skin (new), head & neck (new), central nervous system (new), endocrine & neuroendocrine (new), and eye (new) cancers.
• Lymph nodes for recording a lymph node site (for pathology or surgery) for breast, thoracic, gastrointestinal, female genital (new), genitourinary (new), head & neck (new), and eye (new) cancers.
• Cancer histologies for haematologic, breast, thoracic, gastrointestinal, female genital, genitourinary, soft tissue & bone, skin (new), head & neck (new), central nervous system (new), endocrine & neuroendocrine (new), and eye (new) cancers, based on the WHO Classification of Tumours 5th edition.
• Grading systems for haematology, breast, female genital, and other cancers.
• Staging systems for haematology, breast, thoracic, female genital, colorectal, including clinical, pathological, recurrence or retreatment, and post therapy or post neoadjuvant therapy staging.
• Prognostic scoring systems for haematology, female genital and colorectal cancers.
• Neoadjuvant therapy response scoring systems for breast, colorectal, and female genital (new) cancers.
• Specimen collection procedures to support all cancer types, including colorectal cancers.
• Ancillary study tests and results for breast tumours and a wide range of gene mutation genetic tests (new).
• Additional data to support radiation oncology and systemic anti-cancer therapy treatment plans, including basis of diagnosis, treatment intent, disease response, dose forms, and dose units.

New and updated content

Concept statistics

Requests from the SNOMED NZ National Release Centre to SNOMED International has resulted in the promotion of 13 new concepts into the international edition between period of March to August 2024.

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

There are 2224 new concepts added to SNOMED NZ extension October 2024 release.

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

Description statistics 

There are 7571 new descriptions added to our October 2024 release.

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

Reference sets

There are 677 reference sets in the April 2024 release including 184 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 October 2024 release.

Maps

Five maps between SNOMED CT and other code systems are contained in the October 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 refined implementation of Annotations, we are updating all Extensions in order to align them with the updated version of the refsets in the International Edition Release package (which were first published in June 2024).

• • The languageCode field was specified as the two characters of ISO-639-1 code for the language of the annotation text. The change includes support for specifying dialect when it is applicable by adhering to RFC 5646, which allows the combination of two characters of ISO 639-1 code and two uppercase letters of country code (ISO 3166) separated by a hyphen.  The changes apply to both the Member Annotations String Value Reference Set + Component Annotation String Value reference set:
    • The column "languageCode" has therefore been changed to "languageDialectCode".
      • Component Annotations (1292992004)
        • OLD:    id    effectiveTime    active    moduleId    refsetId    referencedComponentId    languageCode    typeId    value
        • NEW:   id    effectiveTime    active    moduleId    refsetId    referencedComponentId    languageDialectCode    typeId    value
      • Member Annotations (1292995002)
        • OLD:   id    effectiveTime    active    moduleId    refsetId    referencedComponentId    referencedMemberId    languageCode    typeId    value
        • NEW:  id    effectiveTime    active    moduleId    refsetId    referencedComponentId    referencedMemberId    languageDialectCode    typeId    value

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.