I would like to pick up a discusssion we started in the ADL2 meeting last year in Braunschweig:
We had another request (this time from HiGHmed) to support open/extensible set of codes in a DV_CODED_TEXT.
In this case, the reason is that they cannot standardise all codes across the various sites, but wherever it is possible they want to use the available codes as defined. You will probably have seen various variations of such a request (e.g.: we cannot use Snomed, but need to use another terminology; we can only mandate a few, but then there may be more from the same terminology; we want to use our codes where possible, but need normal free text as well.)
To my knowledge there is not really a good way of supporting these use cases, neither in 1.4 nor 2.0.
Some have argued this should not be done, and this had been my opinion a few years ago as well, but for better or worse, I do not think we can or should ignore this any longer. The reason is that ignoring these requirements will only lead to workarounds we like even less from an idealistic point of view, there is no hope that these requirements go away in the next couple of years or even decades.
In any case, even if this does not result in a spec change but a clear recommendation of what to do (and not do) in such cases, that would valuable as well.
See a summary of the initial discussion at https://openehr.atlassian.net/wiki/spaces/ADL/pages/386007225/Local+Value-set+Replacement - We had identified 3 “Candidate Solutions”:
- use a choice of DV_CODED_TEXT + DV_TEXT
- subsumption code + reduction redefinitions
- new required markers - such as a required flag on C_TERMINOLOGY_CODE or a recommendation: required | preferred | example - the latter is to what FHIR is doing if I remember correctly.
The concrete example is a DV_TEXT that is coded using terminology in the oet. But oet’s limit-to-list flag cannot applied in this case (-> the corresponding list_open flag is on CString cannot be applied on the Code Phrase). In case you are interested in the details of this example, see https://ckm.highmed.org/ckm/templates/1246.169.69/27 (Look for: Probenart). In addition, the “limit-to-list” discussion from the Braunschweig meeting is also related: https://openehr.atlassian.net/wiki/spaces/ADL/pages/386007194/OET+Template+-+Limit-to-list
From my point of view, I think we need to discuss what could be allowed in addition to the codes available in the coded text, and how this could be expressed:
- any (free or coded) text
- any other codes from the same specified terminology (snomed)
- any other other codes from any terminology
The first is what HiGHmed need, and what is probably the most common requirement, and maybe all that is required.
Anyway, I hope we can continue the Braunschweig discussion and come to a conclusion.