I listened to a discussion on Thursday's Structured Documents Work Group call about PCAST, UEL and the relationship to the templated CDA that HL7 uses. We had an earlier discussion about "green CDA".
As often happens, later in the day, it occurred to me that perhaps the UEL that PCAST is seeking could be met by "greening of templated CDA entries." Let me explain.
The President's Council on Science and Technology has called for the development of a Universal Exchange Language to exchange "atomic" health data. They feel that the current exchange standards are not granular enough.
HL7 feels that templated CDA should be sufficient and there is concern that an attempt to get too granular will result in data that lacks context and therefore meaning.
Green CDA is an attempt to create a simpler version of the xml than that which CDA currently is, and to provide transforms that will take a "full CDA" document and transform it into a "green CDA" document, and vice versa. The transforms will allow developers that are comfortable with "full CDA" to use that and to exchange documents with developers (and their systems) that are more comfortable with the simpler "green CDA."
Now, it occurs to me that we can use the concept of the "full to green" translation to take the full, templated CDA and extract the UEL molecule and transform the data into "green UEL." The process of moving from full to "green UEL" should maintain sufficient meta data in the molecule to maintain context.
The translation from the "green UEL" to "full CDA" is trickier and may require fetching data from elsewhere to reassemble a proper "full CDA" instance.
I'm not sure that this is a solution, but it just might work.