Table Of Contents

Introduction

Background

SNOMED CT 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 April 2026 release of SNOMED Clinical Terms^® (SCT) International Edition.

It also includes 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 April 2026 International Edition.

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.

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 April 2026 International Edition.

Please note, you may have to register for a user account in order to access the links included in these release notes.

Content Development Activity

Summary

Continuous quality improvement and enhancement of existing content is an ongoing process undertaken by SNOMED International in preparation for every release. The April 2026 International Edition has seen a continuation of the work driven by contributions from: Kaiser Permanente i.e. 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 advanced via project driven initiatives summarized below.  Additional work items impacting every release are updates to the SNOMED CT derived maps such as ICD-10 and ICD-O; details are 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 here.

Quality Assurance

Update Descriptions for Ulcer and Ulceration

A request was received from the Translation User Group to review the descriptions for 429040005 |Ulcer (disorder)| and subtypes. There was inconsistent use of 'ulcer' (morphology) vs. 'ulceration' (process) and the aim of the update was to standardize these concepts. To align with clinical documentation patterns and morphological findings, concepts previously using 'ulceration' have been updated to 'ulcer' where the morphology is the primary focus.

These changes are part of the work for this Content Tracker.

Future changes planned: Alignment of finding site to represent skin of X body structure has been proposed.

Number of concepts edited (approx): 121

Revision of Concepts Using the Term ‘Physiatric’

A review of procedure and regime/therapy concepts containing the term 'physiatric' has been undertaken. The term physiatric has been identified as non-international, outdated and now superseded by nonsurgical manipulation procedures. As part of this work, 12 concepts with physiatric in their FSN have been inactivated with reason outdated and historical association to a nonsurgical manipulation procedure concept. Three synonyms including the term physiatric have also been inactivated.

74251004 |Physiatric mobilization of joint (regime/therapy)| has been updated with the existing synonym retained as PT 'Mobilization of joint', and with no change to modeling. Regime/therapy concepts referring to spinal mobilization have also been updated.

These changes have been implemented for this Content Tracker.

Number of concepts edited (approx): 34

Inactivation of Attention to <device> (procedure) Concepts

Approximately 80 procedure concepts with 'attention to' in the descriptions have been inactivated with reason ‘Nonconformance to editorial policy’ because they do not comply with the precoordination pattern here.

360147003 |Attention - action (qualifier value)| has also been inactivated.

Percutaneous Value for Access

In the procedure hierarchy and where required, the Access attribute with value Percutaneous has been added for concepts where percutaneous is specified in the FSN. Where percutaneous is not specified in the FSN and where it is possible to carry out the procedure by a route other than percutaneous, new concepts have been added with Percutaneous specified in FSN and with modeling ACCESS attribute = PERCUTANEOUS.

The changes are being undertaken for this Content Tracker.

Number of concepts edited (approx): 20

Body Structure 

SEP and Laterality Anatomy Reference Sets

The release file for the lateralizable body structure reference set has been updated and validated.

The release file for the SEP reference set has been updated and validated.

Procedure

Stoma/Ostomy Care Procedure Concepts

Improvements have been made in a small area of content related to stoma/ostomy care procedures. These changes include inactivation of << 1287775006 |Attention to stoma (procedure)| with reason ambiguous together with a review of <<385712009 |Ostomy care (regime/therapy)| and << 225194008 |Stoma care procedure (regime/therapy)| as the terms stoma and ostomy are used interchangeably when relating to care procedures.

Pharmaceutical/Biologic Product

Update Case Significance for Abbreviations of Drug Unit

Descriptions that include abbreviations for the drug unit such as ‘mg’ ‘g’ and ‘mg/’ 'unit/g', 'unit/mg', 'microgram/g' and 'microgram/mg' have been updated to ‘Only initial character case insensitive (core metadata concept)|’ - First character of the description may or may not be capitalized while the case of the rest of the description cannot be changed. For example:

• 3500544012 | Acetaminophen 500 mg oral tablet|

• 3692869013 | Betamethasone (as betamethasone dipropionate) 500 microgram/g and salicylic acid 30 mg/g cutaneous ointment|

• 4550119010 |Cyclophosphamide 500 mg powder for solution for injection vial|

are all now labeled ‘Only initial character case insensitive (core metadata concept)|’.

The Editorial Guide has been updated to align with this change.

These changes have been implemented following consultation, for further information please see this Informational Briefing Note.

Inactivation of 349365008 |Herbal medicine (product)| 

349365008 |Herbal medicine (product)| has been inactivated because it is jurisdictional; its definition varies by country.

Collaboration/Harmonization Agreements

Convergent Medical Terminology (CMT)

36 new CMT disorder concepts have been added for the April 2026 release with a key focus on injuries, together with a small number of other finding and disorder concepts.

Orphanet

Working in collaboration with Orphanet efforts are ongoing to update rare disease concepts in SNOMED CT to maintain alignment with Orphanet for the annual update of the SNOMED CT to Orphanet Maps. This map is at disorder level. In scope content has been annotated with attribution to Inserm Orphanet.

All of the concepts added for the Orphanet project have been mapped to ICD-10.

International League Against Epilepsy (ILAE)

In line with approved harmonized terminology, this project is working on alignment including restructuring to update the hierarchy  << 313307000 |Epileptic seizure (finding)|.

Further information about this collaboration is available here.

Internal Quality Improvement

Machine Readable Concept Model (MRCM) Changes

No changes have been made for the MRCM in the April 2026 International Edition.

Future changes that are currently in progress can be viewed via the MRCM Daily Build Browser

Please see Early Visibility Release Notifications for future planned changes to MRCM.

Annotation Reference Set

The addition of content for the Annotations refset was commenced in the July 2024 International Edition release and is ongoing for attribution of in scope content that is part of a collaboration agreement. Where content with attribution no longer falls into scope for a collaboration agreement, the attribution has been inactivated.

SNOMED CT derived products

SNOMED CT - ICD-10 map

The SNOMED CT to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (© World Health Organization 1994) 2016 Version map (SNOMED CT to ICD-10 Map) is included in the SNOMED CT International Edition 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 Centers.

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_20200731.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 |SNOMED CT to ICD-10 extended map (foundation metadata concept).

The ICD-10 Mapping Technical Guide (including exemplars) is here.

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 constrained to subtypes of 404684003 |Clinical finding (finding)|, 272379006 |Event (event)|, and 243796009 |Situation with explicit context (situation)|. The target classification used is the ICD-10 WHO version 2016 (https://icd.who.int/browse10/2016/en#/).

The map provided for this release has been updated and represents a complete map from the April 2026 release of the SNOMED CT International Edition to the ICD-10 WHO version 2016.

This includes:

Mapped content for April 2026 release

• Addition of 395 new mapped concepts

• Updates to 84 existing mapped concepts

• Retirement of 29 mapped concepts

The SNOMED CT to ICD-O morphology map has zero content changes for this release.

We welcome feedback on any issues that users may detect when deploying the map. Issues can be reported to mapping@snomed.org.

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: https://github.com/IHTSDO/snomed-owl-toolkit

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