CDA 101

Clinical Documentation Architecture (CDA) supplies a framework for specifying the full semantics of a clinical document. CDA defines a clinical document as having the following six characteristics: Persistence Stewardship Potential for authentication Context Wholeness Human readability.

Any type of clinical content can be included in the CDA. Some types of typical CDA documents include Discharge Summary, Imaging Report, Admission and Physical, Pathology Report, etc. CDA is being used world-wide. The most popular use is for inter-enterprise information exchange such as what is envisioned for the United States Regional Health Information Organizations (RHIO). Most users are currently in countries such as Finland, Greece and Germany where RHIO type exchange is well established. Future plans in the US include using CDA in the US RHIO(s) and in the US military Health System.

In addition to use by the Regional Health Information Organizations, CDA is the basis of a variety of experimental work within academic medical centers and research institutions. Examples of this are the project on CDA note generation with knowledge management and controlled vocabulary at Columbia-Presbyterian in New York, the work on CDA for decision support at Queen Elizabeth II Hospital/Dalhousie University and the Single Source Proof of Concept at Duke Clinical Research Institute.

CDA-compliant applications have been created by many vendors for document management, viewing and creation. Since CDA uses Extensible Markup Language (XML), it allows for a non-XML body (word, jpg) for simpler implementation. Therefore any web browser such as Microsoft Internet Explorer and Firefox can parse a CDA document and using XSL style sheet covert in to HTML for display. CDA can also be managed by an XML repository.

Implementers have a variety of choices when it comes to document generation. Many dictation/transcription vendors have CDA as an output option. Many EHR vendors can produce CDA documents. E-Form applications have also been produced for use with CDA. One of the biggest existing barriers to CDA generation is when insufficient information is available at the source for conversion. This however has not been a problem thus far from voice-interface or keyboard entry applications.

CDA introduces the concept of "incremental" semantic interoperability. This means that there is a range of complexity allowed within the specification and that users must set their own compliance. The minimum clinical data architecture required are small XML metadata fields including provider name, document type, document id, etc).

The body must also be any commonly used Multipurpose Internet Mail Exchange (MIME) type such as a .doc, a .pdf or even a scanned image. The minimal standard metadata set and display characteristics mean that documents could be filed and categorized. They would also be searchable and could be retrieved along with more richly encoded documents. This would make them all easily readable at the point of care.