CDAClinical Document Architecture
In short
CDA is the HL7 standard for representing clinical documents (a discharge summary, an imaging report, a referral) so that a person can read them and a system can process them. Each document keeps its authorship, its context and the possibility of being signed. HL7 cites its use in exchange networks in the US, Europe, Australia and New Zealand.
- Type
- Standard
- Steward
- HL7 International
- Current version
- R2.0 (Online Edition 2024)
- Reviewed
- October 25, 2026
Explanation
What it is
The Clinical Document Architecture (CDA) is an HL7 International standard, derived from the HL7 Version 3 framework and its Reference Information Model (RIM), that defines the structure and semantics of "clinical documents" in XML. HL7 attributes six characteristics to a clinical document: persistence, stewardship, potential for authentication, context, wholeness and human readability.
The current normative version is Release 2.0. ISO published it as ISO/HL7 27932:2009, and its 2024 online edition was approved as an ANSI standard on 20 August 2024. HL7 acknowledges that Release 2.1 did not achieve industry adoption and expects future work on structured documents to focus on FHIR.
How it works
A CDA document has two parts:
- Header: patient, author, custodian, date, document type, participants and, where applicable, legal authentication.
- Body: either a non-XML file (a PDF or a scanned image) or a structured body made of sections, each with human-readable text and, optionally, coded entries.
HL7 calls this incremental semantic interoperability: a country or project can start with a header and a PDF, then add structure and coding section by section.
In practice, CDA is used through templates that constrain the standard for a specific case. One example is Consolidated CDA (C-CDA), a US realm guide; as of October 2026, its current version is 5.0.0 (June 2026).
Common misconceptions
- CDA is not a transport protocol. It defines the document; sending or registering it relies on, for example, IHE profiles.
- A CDA document that is valid against the schema can be useless to a system if it does not follow the agreed templates.
- The human-readable text is what gets displayed and authenticated: coded entries must be consistent with it.
- CDA did not become obsolete with FHIR. It is still cited in regulations in several countries, and the IPS also has a CDA representation.
Usage examples
In the US, ONC (formerly ASTP/ONC) certification § 170.315(b)(1) requires creating and receiving C-CDA documents, such as the CCD, the referral note and the discharge summary.
According to HL7, in the US Sequoia/eHealth Exchange supports the exchange of billions of CDA documents every year.
HL7 cites MyHealth@EU, the European Union's cross-border health data exchange service, as a CDA use case.
According to HL7, Australia and New Zealand, among other countries, use CDA widely and with multiple document types.
HL7 publishes a CDA R2 guide for the International Patient Summary, an alternative to the FHIR guide.
Part 20 of the DICOM standard defines how to write imaging reports as CDA documents.
Relation to other terms
Sources
- HL7 — CDA® Release 2 (product brief)hl7.org
- HL7 — ANSI Approved Standardshl7.org
- ISO/HL7 27932:2009 — HL7 Clinical Document Architecture, Release 2iso.org
- HL7 — Consolidated CDA (C-CDA)hl7.org
- ONC — § 170.315(b)(1) Transitions of carehealthit.gov
- DICOM PS3.1 — Introduction and Overview (PS3.20: Imaging Reports using HL7 CDA)dicom.nema.org
- Federal Register — HHS Statement of Organization: Office of the National Coordinator for Health IT (91 FR 16204, 1 April 2026)federalregister.gov