Accessing the LOINC Ontology from a FHIR Terminology Server
When working with the LOINC Ontology, leveraging a FHIR terminology server can simplify access and management. The server allows you to handle the content as a specific CodeSystem version, providing access to all FHIR Terminology operations.
LOINC Extension FHIR URIsing
The SNOMED International URI standard specifies that identify unversioned editions (i.e. editions) and versioned editions (i.e. versions) take the following respective forms:
These URIs apply to the 'version' element of codes and the 'URL' parameter in FHIR Operations. The 'system" element value is always 'http://snomed.info/sct' for all SNOMED editions. For more information on the URI Specification, please refer to the document.
The following table shows some examples of URIs for editions and versions relevant when working with the LOINC Ontology.
Resource
URI
The following table lists a few key requests relevant for retrieving content from the LOINC Ontology using the FHIR Terminology services API.
Service Name and Status
Input
Output
Please refer to the for a comprehensive guidance on SNOMED CT enabled terminology services.
These examples use the concept as the refsetId.
Service Name
API Call
Result
SNOMED CT-LOINC, 31 March 2025
$validate-code
Test if a concept or description is a member of a specified reference set
REQUIRED
A reference set specified by its refsetId
A candidate
If the candidate concept is a member of the reference set: TRUE
Otherwise: FALSE
Test if a concept is a member of the reference set
for example
Returns a JSON object with a "Parameters" resource, including a "result" parameter with a boolean value (true/false) indicating whether the member validated OK or not against the reference set.
GET [fhir]/ValueSet/$validate-code
?system=http://snomed.info/sct&code=537131010000109 &url=http://snomed.info/sct/[moduleId]/version/[effectiveTime]?fhir_vs=refset/[refsetId]
GET [fhir]/ValueSet/$validate-code
?system=http://snomed.info/sct&code=537131010000109 &url=http://snomed.info/sct/900000000000207008/version/20200131?fhir_vs=refset/635111010000100