OID Registry
Browse 6,700+ HL7-registered Object Identifiers
Object Identifiers (OIDs) are globally unique, hierarchical identifiers used throughout HL7 standards to identify code systems, organizations, value sets, and other artifacts. The OID registry contains 6,700+ entries aggregated from HL7 v2/v3 specification data, the HL7 Terminology (THO) package, and FHIR packages.
How OIDs Are Used
Code System Identification
Every vocabulary has an OID (e.g., 2.16.840.1.113883.6.1 for LOINC) used in CWE.3 and CDA code/@codeSystem
Organization Identifiers
Healthcare organizations register OIDs to identify their systems, facilities, and assigning authorities
Value Set Identifiers
Value sets are identified by OID in CDA templates and conformance profiles
FHIR urn:oid: URIs
FHIR uses urn:oid: URIs to reference OID-identified systems when no canonical URL exists
The HL7 OID root is 2.16.840.1.113883. Most healthcare OIDs branch from this root. The registry includes sub-trees for code systems (.6), value sets (.11), and organizations (.3).