VetSCT Frequently Asked Questions

Frequently Asked Questions

This page addresses common questions about the use, implementation, and governance of the Veterinary Extension of SNOMED CT (VetSCT). The goal is to clarify how VetSCT is intended to be used, reduce common points of confusion, and support correct implementation for clinical, research, and regulatory purposes.

VetSCT and the SNOMED CT International Release

Who maintains and governs VetSCT?

VetSCT is maintained by Veterinary Terminology & Standards (VTS) at the Virginia-Maryland College of Veterinary Medicine, Virginia Tech. Governance activities are coordinated with SNOMED International to ensure alignment with extension principles, modeling standards, and release policies.

Can VetSCT be used by itself?

No. VetSCT cannot be used as a standalone terminology.

VetSCT is an extension of SNOMED CT and must always be used alongside a compatible SNOMED CT International Release. Many veterinary-relevant concepts are maintained in the Core SNOMED CT content, and a complete view of the terminology requires both.

What content belongs in VetSCT versus the SNOMED CT International Release?

As a general principle, VetSCT is intended to manage veterinary-specific content, while the SNOMED CT International Release manages core concepts intended for broad, cross-domain use. At this time, VetSCT scope includes veterinary-specific concepts, all breeds, and selected macroorganism content needed to support veterinary use cases.

Can content move between VetSCT and the SNOMED CT International Release?

Yes. In some cases, content is created in VetSCT first to meet urgent needs, such as USDA regulatory reporting, and may later be promoted into the SNOMED CT International Release when it is determined to have broader applicability. Conversely, content that is identified as primarily veterinary-specific may be moved from the International Release into VetSCT to keep the International Release focused on globally applicable core content. Moduleids are to used to note the location of the content.

Browsers, Files, and Distribution

What files are included in a VetSCT release?

VetSCT releases include only extension content. They are intended to be loaded alongside the appropriate SNOMED CT International Release and do not duplicate SNOMED CT International Release files.

Why must VetSCT be released in coordination with SNOMED CT International?

VetSCT content depends on concepts and modeling maintained in the SNOMED CT International Release. When VetSCT and the International Release are updated separately, there can be periods where concepts are inactive in one release but not available in the other, causing data inconsistencies. Coordinated releases help prevent mapping errors, loss of access to needed concepts, and downstream issues in clinical, research, and regulatory systems.

How do I know which International Release to use with VetSCT?

Each VetSCT release is compatible with a specific SNOMED CT International Release. Both must be loaded together to reproduce the full content seen in the VTS SNOMED Browser. Compatibility information is provided with each VetSCT release.

Can national editions use VetSCT content?

Yes. National Release Centers and international users may incorporate VetSCT content into their editions. Users should be aware of dependencies between extensions and the potential for duplication if local extensions also contain veterinary-related content. VetSCT is intended to contain veterinary specific concepts, but some content may be staged for future promotion to the International Release. Careful review during implementation helps manage overlap.

Where can the most current VetSCT release be obtained?

VetSCT release files can be obtained on this website by logging in and navigating to Project – VetSCT. Release files are also available through the SNOMED Member Licensing and Distribution Service (MLDS). International users are encouraged to use the MLDS resource for access.

I have the most current VetSCT release loaded, but I see concepts in the Browser that are not in my system. Why?

The VetSCT Browser is updated more frequently than the biannual release files. Therefore, new or changed content may be visible in the browser before it is available in official releases.

While content identifiers are generally maintained, permanence between releases cannot be strictly guaranteed. Caution should be exercised when using interim browser-only content in production systems.

Licensing and Access

Do I need a SNOMED CT license to use VetSCT?

Yes. Because VetSCT is an extension of SNOMED CT, use of VetSCT is subject to SNOMED CT licensing requirements. Users are responsible for ensuring appropriate licensing through their National Release Center.

The National Library of Medicine is the United States release center. US organizations wishing to implement the VetSCT can easily obtain access by obtaining credentials with NLM’s UMLS Terminology Service.

For those outside the US, you can find your national release center by clicking on your country on Snomed’s Member page. If you or your application will be using SNOMED in a country that is NOT a member of SNOMED, you must contact SNOMED directly to discuss licensing.

How do I obtain access to VTS resources?

Much of our site is available for use without credentials. Areas such as the VetSCT Browser (which only requires you to agree to a browser license agreement if you are not logged in), USDA resources, and general information are all available without logging in. If you need to download the files for VetSCT or one of its derivatives (subsets), you will need to log in.

Users in the United States are granted access using their UMLS authentication (see License information above). Users outside of the US must first obtain proof of licensing from their National Release Center or from SNOMED, then contact us to obtain local account for our site if needed. Reminder to International users, the extension files are available via MLDS, however our subsets are managed and distributed locally. If you desire access to downloads of our subsets, then you will need to obtain access to our site.

Implementation and Use

Is VetSCT intended only for veterinary clinical records?

No. VetSCT is intended for use across veterinary clinical records, research datasets, and regulatory or surveillance reporting. Its purpose is to support standardized, interoperable animal health data.

Can VetSCT be used in production systems?

Yes. VetSCT is a maintained SNOMED CT extension and is appropriate for production use when implemented according to SNOMED CT standards and licensing requirements.

Core Usage and Concept Lifecycle

How do I find replacements for retired concepts?

When a SNOMED CT or VetSCT concept is retired, it is not deleted from the terminology. Instead, SNOMED CT provides historical relationships that indicate how an inactive concept should be handled moving forward.

Historical relationships are stored as historical association reference sets in SNOMED CT and can be found in the following file:

der2_crefset_associationreference.txt

Each row represents a relationship between a retired concept and another concept. For example, a REPLACED BY association identifies the concept that should be used in place of the retired one.

Key fields include:

referencedComponentId – the retired concept SCTID
refsetId – the type of historical association
targetComponent – the replacement concept SCTID

Multiple historical association types exist, not just REPLACED BY. The complete list is available as descendants of:

138875005 |Historical association (foundation metadata concept)|

At this time, VTS does not provide an API that allows direct queries for replacement concepts. However, the same historical relationships visible in the VTS SNOMED Browser are available in the SNOMED CT release files.

Why are concepts retired instead of deleted?

Concepts are retired rather than deleted to preserve the integrity of existing data. Retired concepts may still appear in historical datasets, clinical records, or research databases. Historical associations provide guidance for interpretation and transition without invalidating prior data.

What should I do if my system contains retired concepts?

Retired concepts may remain in historical data. For active use, systems should reference historical association data to determine appropriate replacement concepts and update workflows or value sets accordingly.

Requests, Support, and Governance

How do I request new VetSCT content or report an issue?

Requests for new concepts, new descriptions, and concept changes can be submitted via our Content Request System. Issues may also be reported via email at vtsl.info@vt.edu.

Why might a content request be placed on hold or declined?

Requests may be placed on hold or declined due to modeling constraints, overlap with existing SNOMED CT content, or the need for additional clinical or use case justification. VTS aims to maintain alignment with SNOMED CT governance principles.

For additional questions, please contact Veterinary Terminology & Standards (vtsl.info@vt.edu).