6.2 Relationship to other standards

LOINC document codes are created with the intention of supporting a robust international document exchange. To allow for this, LOINC actively participates in associated standards development. The success of the LOINC document representational approach includes the following examples.

6.2.1 HL7 Clinical Document Architecture (CDA)

CDA requires a document type code, and LOINC is the standard vocabulary most commonly used to identify the document’s clinical type (e.g., discharge summary, operative note, imaging report).

Many implementation guides mandate LOINC codes for the CDA code element.

6.2.2 HL7 FHIR

FHIR uses LOINC document codes in:

• DocumentReference.type
• Composition.type
• Many U.S. and international implementation guides (e.g., U.S. Core, IPS).

6.2.3 IHE Cross-Enterprise Document Sharing (XDS) and Related Profiles (XCA, XDR, XDM)

IHE profiles require document type identification; LOINC is the standard vocabulary for the XDS “Class Code” and/or “Type Code,” depending on the profile and deployment.

6.2.4 U.S. regulations

U.S. regulations and programs that build on HL7/IHE Meaningful Use / Promoting Interoperability programs adopted CDA and FHIR document exchange requirements that rely on LOINC document codes. United States Core Data for Interoperability (USCDI) references LOINC for document types in FHIR-based exchange.

6.2.5 International standards and national exchange frameworks

Many national health information exchange frameworks (e.g., Canada, several EU countries, Australia implementations) adopt LOINC document codes through CDA, FHIR, or IHE-based infrastructure.