This chapter describes how the GPS may be accessed, deployed, and used in practice, while remaining within its intended scope and respecting SNOMED CT licensing requirements.

The guidance in this chapter focuses on safe, predictable, and license-compliant use of SNOMED CT identifiers and terms.

Accessing the Global Patient Set

The GPS is made available by SNOMED International for download under a Creative Commons -NoDerivatives 4.0 International Public License (CC BY-ND 4.0).

Access to the GPS:

• does not require SNOMED CT Membership

• does not require a SNOMED CT Affiliate License

The GPS is accessed via the GPS page on the SNOMED International website.

This distribution mechanism allows SNOMED International to:

• publish authoritative GPS releases

• notify users of updates and changes

The GPS is distributed as a standalone release artifact and may be used independently of the full SNOMED CT release.

Implementation Approaches and Key Considerations

The GPS is designed to enable global access to SNOMED CT identifiers and terms, while preserving the licensing model for SNOMED CT as a semantic terminology.

Implementers should clearly distinguish between:

• identifier-level use, which is supported by the GPS, and

• semantic or ontology-based use, which requires licensed access to the full SNOMED CT release

Uses Supported by the GPS

Using the GPS, systems may:

• receive and exchange SNOMED CT identifiers

• store SNOMED CT identifiers with associated terms

• display SNOMED CT terms for human interpretation

• validate identifiers against an authoritative list

• support interoperability across licensing and national boundaries

These uses are permitted in all jurisdictions, including non-Member countries.

Uses Requiring Licensed SNOMED CT Access

Any use that depends on knowledge of SNOMED CT concept semantics requires licensed access to the full SNOMED CT release.

This includes, but is not limited to:

• use of subtype (IS-A) hierarchies

• querying parent, child, or ancestor concepts

• creating subsets or value sets based on hierarchical inclusion

• subsumption testing or reasoning

• use of logical definitions or attributes

• terminology-driven decision support or analytics

These capabilities must not be implemented using the GPS alone.

Deploying and Using the GPS

When deploying the GPS, systems should treat it as a flat collection of identifiers and terms, without semantic structure.

Recommended practices include:

• treating each SNOMED CT identifier as an opaque, standalone code

• avoiding assumptions about relationships between concepts

• not inferring broader, narrower, or related meanings

• storing the GPS release version alongside stored identifiers

Where systems operate in both licensed and unlicensed environments, GPS-based functionality should be clearly separated from functionality that relies on the full SNOMED CT release.

This separation supports:

• licensing compliance

• predictable system behaviour

• clear communication of system capabilities

Operational Considerations

Operational use of the GPS should take the following into account:

Version Management

Systems should track which GPS release is in use, particularly when storing data long-term.

Handling Inactive Concepts

Concepts may become inactive between GPS releases. Systems should define local policies for the display and handling of inactive identifiers.

Coexistence with Local Codes

GPS identifiers may coexist with local codes or classifications to support continuity of care and local workflows.

Provide Feedback

Semantic Tag–Based Filtering

SNOMED International makes available a tool to filter the downloaded GPS files based on a concept's fully specified name (FSN), which allows implementers to restrict GPS content to a specific clinical domain:

https://ihtsdo.github.io/snomed-gps-extractor/

Semantic tags are derived from the FSN and can be used to:

• Include or exclude concepts based on high-level meaning (e.g. disorders, findings, substances)

• Produce domain-specific GPS subsets

• Reduce dataset size for constrained or focused implementations

How to Use the Tool

Your file is processed locally in the browser and is never uploaded to any server.

1. Upload: Drag and drop the downloaded SNOMED CT GPS file (TSV format).

2. Configure:

   • Toggle "Active Concepts Only" to exclude inactive records.

   • Select the desired Semantic Tags from the categorized list.

   • Add any Custom Tags if needed.

3. Process: Click "Process & Download" to get your filtered dataset.

There is also a Command-Line Interface (CLI) included in the GitHub repository, intended for automated and repeatable processing, such as CI/CD pipelines or scheduled dataset builds.

GPS Extractor Tool

This is a utility tool for extracting and processing SNOMED CT terminology data from an RF2 release. It produces the SNOMED International GPS (Global Patient Set) format and offers advanced filtering capabilities via both a command-line interface (CLI) and a modern web interface.

Role in GPS Implementations

Implementers may need to recreate the Global Patient Set (GPS) from an existing SNOMED CT Edition RF2 distribution into formats suitable for runtime use in applications, such as value sets, lookup tables, or terminology service artifacts. The snomed-gps-extractor tooling supports this process by providing a repeatable way to extract, normalize, and package GPS content from official SNOMED CT RF2 release files.

In a typical GPS implementation, the term extractor is used to:

• Produce a flat list of SNOMED CT concepts and terms without hierarchical or relational semantics

• Enable implementers to tailor GPS datasets to specific clinical or interoperability use cases

The extractor acts as a bridge between the full GPS and implementation-friendly artifacts, such as value sets or lookup tables.

Features

The SNOMED CT GPS Term Extractor provides the following capabilities to support GPS content preparation:

• Term extraction from RF2

• Semantic tag–based filtering

• Interactive web-based processing

• Active status filtering

• Command-line execution

Term extraction from RF2

The extractor provides a controlled mechanism for deriving GPS-ready datasets from SNOMED CT RF2 releases by standardising how concepts and terms are selected and represented. This supports repeatable dataset generation across releases and reduces the need for custom RF2 processing logic within implementations.

The extracted output is designed to be stable and comparable over time, enabling consistent downstream use in exchange, indexing, and validation scenarios.

Active Concept Management

The extractor supports handling of concept lifecycle status, enabling implementations to:

• Include both active and inactive concepts where historical traceability is required

• Restrict outputs to active concepts only for current-state exchange and display use cases

This allows implementers to align GPS datasets with their data governance and clinical safety requirements.

Output Characteristics

The extractor produces GPS-compatible tab-separated files (TSV) designed to be:

• Easy to inspect and validate

• Simple to load into databases or terminology services

• Straightforward to transform into other representations (e.g. FHIR ValueSet resources)

Relationship to Full SNOMED CT Implementations

The GPS term extractor does not generate:

• Concept hierarchies

• Attribute relationships

• Subsumption or inference logic

Implementations requiring full semantic reasoning or advanced terminology services should use a licensed SNOMED CT edition and a dedicated terminology server instead of GPS-derived artifacts.

Operational Guidance

Detailed operational guidance for installation, command-line usage, web interface operation, and configuration options is maintained in the GitHub repository for the SNOMED CT GPS Term Extractor. Implementers should refer to the repository documentation for the most current and authoritative instructions.

Provide Feedback

The Global Patient Set (GPS) may be used as a content source for a FHIR terminology server in environments where licensed access to the full SNOMED CT release is not available. In such configurations, the GPS supports identifier-level terminology services only and must not be treated as a substitute for a full SNOMED CT terminology server.

GPS content used by a terminology server is typically prepared in advance from SNOMED CT RF2 releases using tooling such as the SNOMED CT GPS Term Extractor, which derives a flat, GPS-compatible dataset suitable for loading into terminology services.

Supported Terminology Server Capabilities

When configured with GPS-derived content, a FHIR terminology server may support a limited set of operations that rely solely on identifiers and human-readable terms, including:

• $lookup for SNOMED CT concept identifiers

• $validate-code to confirm identifier validity and active status

• $expand for value sets uploaded by the user

Responses are limited to concept identifiers and associated term information and must not include semantic relationships, hierarchies, or inferred data.

A FHIR terminology server configured with the GPS must not support terminology services that require access to SNOMED CT semantics.

This includes, but is not limited to:

• subsumption testing

• hierarchical navigation or expansion

• $expand operations based on SNOMED CT hierarchies

• use of Expression Constraint Language (ECL)

All such capabilities require licensed access to the full SNOMED CT release.