This was (and still is) hotly debated within the INTEoPEN Care-connect curation group.
There are very, very few international Observation profiles or ObservationDefinitiions (and diasagreement on which to use!).
THere is some useful guidance on use of SNOMEd CT in Observations
but beyond the NEWS2/Vital signs work we dod for Care-Connect, and a whole bunch of Child health Observation profiles (developed independently and never curated), most is being done ad-hoc.
Some people think we should not bother to spend time and effort (and it is a lot of effort) to discuss, decide on standardising use of units, sensible ranges etc. The argument is that this kind of ‘validation’ is best left to the importing system.
This kind of validation is exactly what we are aiming for in openEHR - so if you look at
You will see the UCUM units defined (there are a whole bunch more) .
We have to do this since when we persist data an openEHR-based system, these archetypes do act exactly as if they were the database validation layer i.e send wrong UCUM unit and you get a server validation error.
We have also being doing some work around generating various FHIR artefacts from openEHR archetypes - no reason why we couldn’t generate the ObservationDefinition that way @Kevin_Mayfield -what do you think?