There is little doubt what the theme was for the HL7 International booth at HIMSS11. The color of the booth was dominated by green with the intent of promoting their new greenCDA standard. On Monday of the show, an HL7 press release was announced giving a hint at the new greenCDA standard to come sometime in March 2011.
There were learning sessions throughout the show which gave us some insight to greenCDA, and why it was created. It is touted as “simple and intuitive” in the press release. Of the information that has been released so far, it seems like the following characteristics are what backs that statement:
- A preference for elements instead of attributes in the XML coding
- The elements use ‘Business Names’ that are easily understood
- Using simple datatypes over complex datatypes
- Eliminating cryptic xsi:type’s
- Using XHTML for narrative text
- Storing static value sets in the schema or transform
The characteristics above seem to allow for a more easily understood structure. Elements instead of attributes allow for a flatter hierarchy, and having business names takes the confusion out of what a data value represents. Eliminating cryptic coding and static values serves to de-clutter the file.
Since the original CDA has been around for a while, and has been designed into products, there has to be backward compatibility. Thus, HL7 announced there would be a transform (.xslt) with the greenCDA so that any greenCDA could be transformed back into a full CDA. The static values, and other complexities which were stripped out of the greenCDA, would be put back in during the transformation.
At first glance, the greenCDA seems like a great alternative to the full CDA. Anyone who has looked at the schema of the full CDA understands how complex it can become, and trying to decipher what is encoded into to all the attributes can be next to impossible without a thorough understanding of the standard.
I think that simplifying the structure is a step in the right direction as CCD (C32), a constraint on the CDA became a requirement for Meaningful Use. I look forward to the release of the greenCDA implementation guide in March to see if the hype lives up to the expectations of “simple and intuitive.”
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