Example of Metadata Elements Using HL7 CDA R2
Content Data Type
CDA R2 EXAMPLE
Note that in a CDA R2 header, the root
attribute would typically be an OID
Source: ONC HIT Standards Committee. “Metadata Analysis Power Team Recommendations to HITSC.” http://healthit.hhs.
Release 2 (CDA R2) header syntax.
The CDA R2 is a “document markup standard that specifies the
structure and semantics of a clinical document (such as a discharge summary or progress note) for the purpose of exchange.
A CDA document is a defined and complete information object
that can include text, images, sounds, and other multimedia
content. It can be transferred within a message and can exist independently, outside the transferring message.” 3 The standard
allows for flexibility and scalability to support increased information exchange.
The power team believed the following data elements were the
most appropriate in accurately selecting a unique patient from
a population: patient name, date of birth, current zip code, patient identifiers, and address.
Additional recommendations were suggested to modify the
HL7 CDA R2 to add a display name element to accommodate
different naming conventions and the use of a uniform resource
identifier as used in different cultures.
The team recommended the following provenance metadata
elements: tagged data element identifier, time stamp, actor, actor’s affiliation, and actor’s digital certificate. Additional suggestions included use of an X.509 certificate to digitally sign the
envelope contents and additional optional metadata fields.
The team recommended the following privacy metadata elements: policy pointer (e.g., URL poining to current privacy-policy) and content metadata, which stores information about
a piece of content. Additional suggestions included expanding
the HL7 standard sensitivity vocabulary to tag data elements
with detailed attributes conveying patient privacy preferences.
ONC approved the team’s recommendations and believes the
adoption of metadata standards can rapidly advance electronic
HIE despite the various system architectures implemented. In
order to be effective, the standard would need to be updated to
reflect metadata requirements.
In August, ONC issued an advance notice of proposed rule-making seeking public input on metadata standards to support
nationwide electronic health information exchange, with an
immediate scope focusing on summary care records. The rule is
available at www.gpo.gov/fdsys/pkg/FR-2011-08-09/pdf/2011-
1. President’s Council of Advisors on Science and Technology. “Report to the President Realizing the Full Potential
of Health Information Technology to Improve Healthcare for Americans: The Path Forward.” December 2010.
2. “Metadata Management Definition—What Is Metadata?”
3. Dolin, Robert H. et al. “HL7 Clinical Documentation Architecture, Release 2.” Journal of the American Medical
Informatics Association 13, no. 1 (Jan-Feb 2006): 30–39.
Allison Viola ( firstname.lastname@example.org) is director of federal relations at