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 December 2025 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 December 2025 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 December 2025 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 December 2025 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 Initiative

The Quality Initiative (QI) project is the implementation of the Quality Strategy. After a successful pilot project for the July 2018 Edition release, the next stage has been implemented for subsequent releases including December 2025. 

Quality improvement tasks are being deployed to improve internal structural consistency and ensure compliance with editorial policy related to the stated modeling of content. Additionally, correction or addition of defining relationships is being carried out to accurately reflect current clinical knowledge and ensure the semantic reliability of descriptions associated with a concept.

Body Structure 

New Paraspinal Muscle Concepts

The anatomical region of the back is potentially ambiguous as the word 'back' can sometimes be used to refer to the entire length of the spine from the pelvis to the neck; or, alternatively the word can be used in a more narrow sense referring to the structures of the posterior trunk including those related to the thorax (upper back) and the abdominopelvic region (lower back). The anatomical hierarchy has been reviewed and the structures relating to the posterior region of the trunk given more explicit FSNs to make a clear distinction between this region and that of the combination of the posterior region of the trunk AND neck. A new hierarchy relating to the paraspinous muscles has been created and their regional components also categorized under the appropriate cervical, thoracic and lumbar regions.

The concept 280440001 |Regional skeletal muscle structure (body structure) has been inactivated and a new concept added relating to skeletal muscle of the vertebral column.

Number of concepts edited (approx): 30

Update Lymphoid System

The upper levels of the anatomical class related to the lymphoid system has been rationalized. The relationship between the lymphoid system; the lymphatics (including vessels and lymph nodes); the Mononuclear phagocyte system, and the lymphoreticular system has been established. Lymphoid tissue has been made the preferred term of the concept with lymphatic tissue as a synonym, along with the more archaic term lymphocytic tissue.

Number of concepts edited (approx): 10

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.

Clinical Finding

Update Decompression Sickness

Content changes have been made to align with current published information: Decompression sickness (DCS), is also known by synonymous terms like Caisson disease, the bends, and is a disorder caused by the formation of gas bubbles in the body's tissues from a rapid decrease in surrounding pressure. The condition is clinically categorized into two main types:

• Type I - the milder form, primarily affecting the musculoskeletal system. Symptoms include joint and muscle pain, fatigue, and skin issues.

• Type II - the more severe and potentially life-threatening form. It involves the central nervous system, leading to serious neurological symptoms like paralysis, sensory loss, and cognitive impairment.

Divers palsy, Divers paralysis have been placed as synonyms on 212954004 |Decompression sickness type II (disorder)|

Bends has been retained as a generalized concept for decompression sickness with Caisson disease as synonym.  

Number of concepts edited (approx): 10

Update Stricture of Urethra

Following a member request suggesting duplication between Traumatic stricture of female urethra (disorder) and Post-traumatic female urethral stricture (disorder), all urethral stricture related content has been reviewed. The 'post-traumatic urethral stricture' concepts have been retained, with 5 'traumatic urethral stricture' concepts inactivated and their descriptions retained as a synonym of the 'post-traumatic' concept.

Concepts Inactivated:

• 86347007 |Traumatic urethral stricture (disorder)|

• 367951000119106 |Traumatic anterior urethral stricture (disorder)|

• 367961000119108 |Traumatic bulbous urethral stricture (disorder)|

• 367971000119102 |Traumatic membranous urethral stricture (disorder)|

• 368981000119103 |Traumatic stricture of female urethra (disorder)|

Number of concepts edited (approx): 10

Update Disorder of Keratinization

277905003 |Disorder of keratinization (disorder)| and related concepts have had the finding site value updated to include skin and mucosa structures.

Inactivation of 30041005 |Acute angle-closure glaucoma (disorder)| and Subtypes

Following review and consensus by the Eye Care Clinical Reference Group, 30041005 |Acute angle-closure glaucoma (disorder)| and its subtypes have been inactivated.

The correct representation is 1111451000000106 |Acute angle closure (disorder)|, with new synonyms (acute angle closure attack, acute angle closure crisis) added to reflect clinical usage. This change aligns with international ophthalmology guidelines, which consistently use acute angle closure rather than acute angle-closure glaucoma.

Procedure

Update Hernia Repair and Hernia Related Procedures

A request has been received to review concepts using the terms herniorrhaphy and hernioplasty as synonyms. In literature the distinction is well established:

• Herniorrhaphy refers to the repair of a hernia by suturing the defect in the abdominal wall.

• Hernioplasty refers to hernia repair that incorporates prosthetic material or grafts.

A total of 126 subtypes of 50465008 |Hernia repair (procedure)| where a suture, device, or substance was involved in the repair, have been reviewed to determine alignment with the definitions of herniorrhaphy or hernioplasty.

Two new grouper concepts have been created:

• Herniorrhaphy (procedure)| – The repair of a hernia by suturing the hernial opening.

• Hernioplasty (procedure)| – The repair of a hernia that incorporates the use of a prosthetic material or substance.

Procedure concepts using the terms herniorrhaphy or hernioplasty have been reviewed. Any descriptions inconsistent with the above definitions have been inactivated. Where a procedure concept matches one of the definitions but the appropriate term is not present in its descriptions, a synonym has been added.

After completion of these changes:

• All procedures with descriptions containing herniorrhaphy have been subsumed by new concept - Herniorrhaphy (procedure)|.

• All procedures with descriptions containing hernioplasty have been subsumed by new concept - Hernioplasty (procedure)|.

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

Number of concepts edited (approx): 126

Reconstruction Using Flap

Updates have been undertaken to align content to the editorial guide in the hierarchies 1380226007|Reconstruction of perineum using flap (procedure)| and 315301002|Reconstruction of vagina with flap (procedure)|.

Number of concepts edited (approx): 7

Update to Aqueous Humor Drainage Device and Related Procedures

Following collaboration with the Eye Care Clinical Reference Group (CRG), an update has been made to the SNOMED CT structure for aqueous humor drainage devices. This update reflects advancements in technology and aims to enhance the clarity of device descriptions.

Details of the device hierarchy structure can be found here.

This change also impacts related procedure concepts, specifically 265291005 |Insertion of drainage tube into anterior chamber (procedure)| and subtypes. The published concepts have been inactivated and replaced due to the following reasons:

• The procedures described are implantations, not insertions.

• Earlier devices typically included plates; however, newer technologies include devices without plates.

• Drainage devices can be implanted in additional anatomical locations, such as the posterior chamber and the vitreous cavity/pars plana.

Example change:

• Inactivation of 265291005 |Insertion of drainage tube into anterior chamber (procedure)|, reason outdated and replaced by:

  • Implantation of subconjunctival aqueous humor drainage tube with plate into anterior chamber (procedure)

  • Implantation of subconjunctival aqueous humor drainage tube without plate into anterior chamber (procedure)

Additional new concepts have been created to represent implantation procedures in other anatomical sites.

Situation With Explicit Context

Concepts That Specify “No Known”

Concepts in the situation with explicit context hierarchy which specify "No known" have been updated.  This follows discussion at the Editorial Advisory Group, where it was agreed a new finding context value should be created. The new concept 1381510001 |No known (qualifier value)| has been added with a textual definition of " No evidence of the specified finding has been identified. It reflects the absence of observed or reported findings, not a guarantee of true absence."  Existing subtypes of 413350009 |Finding with explicit context (situation)| that specify "No known" in the FSN have been updated to incorporate this new value.

Pharmaceutical/Biologic Product

Update to Medicinal Product Strength Representation

Adjustments have been made to 11 medicinal product concepts to align with the SNOMED CT Editorial Guide. The guidance specifies that strengths are normalized and, when the value is less than one, converted to a smaller unit (e.g. if the value is less than one milliliter, convert the value to microliter)

Updated concepts:

• 5411000124106 |Product containing precisely ethanol 0.7 milliliter/1 milliliter conventional release cutaneous solution (clinical drug)|

  • Updated to 5411000124106 |Product containing precisely ethanol 700 microliter/1 milliliter conventional release cutaneous solution (clinical drug)|

• 1179480003 |Product containing precisely glycerol 0.05 milliliter/1 milliliter conventional release oral solution (clinical drug)|

  • Updated to 1179480003 |Product containing precisely glycerol 50 microliter/1 milliliter conventional release oral solution (clinical drug)|

• 895696005 |Product containing precisely helium 0.09 milliliter/1 milliliter and nitrogen 0.56 milliliter/1 milliliter and oxygen 0.35 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 895696005 |Product containing precisely helium 90 microliter/1 milliliter and nitrogen 560 microliter/1 milliliter and oxygen 350 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 895694008 |Product containing precisely helium 0.79 milliliter/1 milliliter and oxygen 0.21 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 895694008 |Product containing precisely helium 790 microliter/1 milliliter and oxygen 210 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 895692007 |Product containing precisely carbon dioxide 0.05 milliliter/1 milliliter and oxygen 0.95 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 895692007 |Product containing precisely carbon dioxide 50 microliter/1 milliliter and oxygen 950 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 895691000 |Product containing precisely carbon dioxide 0.1 milliliter/1 milliliter and oxygen 0.9 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 895691000 |Product containing precisely carbon dioxide 100 microliter/1 milliliter and oxygen 900 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 895690004 |Product containing precisely carbon dioxide 0.2 milliliter/1 milliliter and oxygen 0.8 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 895690004 |Product containing precisely carbon dioxide 200 microliter/1 milliliter and oxygen 800 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 895684003 |Product containing precisely air 0.95 milliliter/1 milliliter and carbon dioxide 0.05 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 895684003 |Product containing precisely air 950 microliter/1 milliliter and carbon dioxide 50 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 895680007 |Product containing precisely nitrous oxide 0.5 milliliter/1 milliliter and oxygen 0.5 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 895680007 |Product containing precisely nitrous oxide 500 microliter/1 milliliter and oxygen 500 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 376525002 |Product containing precisely oxygen 0.995 milliliter/1 milliliter conventional release gas for inhalation (clinical drug)|

  • Updated to 376525002 |Product containing precisely oxygen 995 microliter/1 milliliter conventional release gas for inhalation (clinical drug)|

• 1141797004 |Product containing precisely peppermint oil 0.2 milliliter/1 each gastro-resistant oral capsule (clinical drug)|

  • Updated to 1141797004 |Product containing precisely peppermint oil 200 microliter/1 each gastro-resistant oral capsule (clinical drug)|

Number of concepts edited (approx): 11

Description changes: FSN and PT

Substance

Promotion from LOINC Extension

The LOINC ontology project team has developed approximately 700 new substance concepts in the LOINC extension for DNA, RNA, IgE, IgG, and IgG4, to align with associated LOINC parts e.g., 697041010000101 |Immunoglobulin E antibody to Alnus incana subspecies rugosa (substance)|.

These concepts are internationally applicable and have been promoted to the International edition following the scheduled release of the LOINC ontology V.2.0.

Physical Object

Branded Ophthalmology Devices

An exception to the existing editorial guidance, which prohibits branded devices, has been made to include a select number of branded devices used in glaucoma treatment. The Eye Care Clinical Reference Group agreed on the list of these devices, acknowledging their consistent international use. The exception was necessary due to the challenge of describing these devices clearly and unambiguously in the SNOMED FSN. Since the selection of these devices is based on their brand names, it was essential to include them in SNOMED CT. Attribution has been included with these new concepts.

Collaboration/Harmonization Agreements

Convergent Medical Terminology (CMT)

142 new concepts have been added for the December 2025 release with focus on device malfunctions, musculoskeletal conditions and oncology.

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.

Cancer Synoptic Reporting

Cancer synoptic reports are used by many member countries to record pathology examination of cancer specimens including the College of American Pathologists (US and Canada), Royal College of Pathology (UK), Royal College of Pathology Australasia (Australia, New Zealand), PALGA (The Netherlands), Swedish Society of Pathology, and others.

For more information about this project, please see Cancer Synoptic Reporting Clinical Project Group 

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 December 2025 International Edition.

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

Please see Early Visibility 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 December 2025 release of the SNOMED CT International Edition to the ICD-10 WHO version 2016.

This includes:

Mapped content for December 2025 release

• Addition of 222 new mapped concepts

• Updates to 239 existing mapped concepts

• Retirement of 42 mapped concepts

The SNOMED CT to ICD-O morphology map has no additional new content 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.