Increasing SNOMED International description length limits

SNOMED International has confirmed the planned change to increase the maximum length of Fully Specified Name (FSN) and Synonym descriptions from 255 characters to 4,096 characters.

This change will be implemented in the 1 July 2026 International Edition release and will come into effect in the October 2026 UK Edition release.

See the news article on Delen for more information.

NHS England is seeking views from SNOMED CT users in the UK through a survey to help identify if additional information or support may be needed to prepare for the change, and to understand the most effective ways to communicate and share that information.

Your feedback will help NHS England decide whether further guidance or engagement is required to support users beyond that which SNOMED International is providing.

Please complete the survey by 5pm on Wednesday 10 December 2025.

If you have any issues completing the survey, contact: information.standards@nhs.net

Increasing SNOMED International description length limits

Following the Delen news article on the proposal to increase description length limits, SNOMED International has published a briefing note, available on Delen:

MF Briefing Note - Conclusion on Increasing Description Type length limits

A blog post with further information is also available on the SNOMED International website:

Blog: SNOMED International concludes community feedback period on proposed description character limit increase and finalizes next steps

As SNOMED International has outlined, the change to the description length limits will be implemented in the 1 July 2026 International Edition release. It will take effect in the October 2026 SNOMED CT UK release.

If you have any questions or concerns, email information.standards@nhs.net.

Share your views on SNOMED International's proposal to increase description lengths

We want to update you on SNOMED International's proposal to increase the maximum length of Fully Specified Name (FSN) and Synonym descriptions from 255 to 4,096 characters. More information about this proposal is available in the Delen news article.

The change will affect UK users of content from SNOMED International’s Medicinal Product Hierarchy, whether taken from the SNOMED CT International Edition or the SNOMED CT UK Edition. However, it will not affect the NHS dictionary of medicines and devices (dm+d), and we do not plan to make any dm+d changes in response to this proposal.

We are reviewing how this change might affect FSNs in the SNOMED CT UK Drug Extension, but we do not expect it to affect Preferred Terms (PTs) in the UK Drug Extension.

SNOMED International currently plan to implement this change in January 2026, with it taking effect in April 2026 UK releases.

If UK stakeholders need more time to implement this change or have any questions or concerns, contact SNOMED International directly at:

release@snomed.org

We also request that UK stakeholders copy:

information.standards@nhs.net

so NHS England can stay informed of any feedback.

SNOMED CT International Edition: long descriptions

This announcement affects subscribers to the SNOMED CT International Edition item.

SNOMED International included 2 descriptions in the April 2024 release which were longer than 255 characters. The May 2024 release shortened these descriptions to within the current 255-character limit.

Subscribers to items in the SNOMED CT UK Edition category will only see the shortened descriptions in release content. UK users who use the latest 'Snapshot' file of the International Edition will also only see the shortened descriptions.

Read more on Delen.