LOINC Document Ontology OWL File

The OWL file of the LOINC Document Ontology is a computable format for the hierarchy

OWL is a file format that stands for "Web Ontology Language". In general, knowledge expressed in OWL format is computer-readable and can represent rich knowledge about resources (such as LOINC parts and LOINC terms) and the relationships between them. Since OWL is a standard format for representing ontological information, it is possible to query that knowledge, build visual representations, and make inferences if you have the right tools.

For further information about OWL and ontology, we recommend resources available from The University of Manchester and the World Wide Web Consortium.

TIP For more information on the LOINC Document Ontology, see Section 6 of the LOINC Users' Guide.


The LOINC Document Ontology OWL file has an Alpha status. We do not have a schedule for promoting this artifact to a production status.

Using this file

The LOINC DocumentOntology.owl file can be viewed using an ontology editing and browsing tool such as the open-source Protégé platform from Stanford University. Users who are familiar with such ontology tools should be able to run queries, and view inferences about the relationships between the individual LOINC document concepts.

Protégé hierarchy view of LOINC Document Ontology
Protégé visualization of a Subject Matter Domain within the LOINC Document Ontology
Protégé visualization of a single document within the LOINC Document Ontology

File Contents

The LOINC Document Ontology OWL file is provided in a .zip format that contains a single OWL file formatted in OWL Functional Syntax as well as Release Notes, Readme, and LOINC license files in plain text format.


LOINC Document Ontology (OWL)
Version: 1.5 alpha
Released: 2021-08-23
Size: 280 KB (ZIP)

  • Loinc_2.71_DocumentOntologyOwl_1.5-Alpha
  • DocumentOntology.owl
  • DocumentOntologyOwlReadMe.txt
  • LoincReleaseNotes.pdf
  • Loinc_2.71_License_5.2.txt

API Access

Parts used in the LOINC Document Ontology are available within the CodeSystem resource of LOINC's FHIR Terminology Server. The parent/child relationships for this hierarchy are not yet included.