Sorry, yet another question involved Medications in OpenMRS and mapping them to FHIR.
This is following on from a discussion started on this ticket:
We are looking to map the “Dose” and “Dose Units” components of a Drug Order to the appropriate fields in a FHIR Medication Request. (This currently has not been implmeneted in the FHIR2 module).
The best way to map these two fields appears to be to the following mapping on a Medication Request:
“doseQuantity” is a SimpleQuantity that provides a field for “value”, where’d we’d map the “dose” numeric, and then two fields for the units… one “unit” is more a display value of the unit, while “code” is a coded value for the unit
My question is, what coding system should we use for the coding the unit?
Looking at this ticket here, @ibacher suggests that the preferred approach would be to map to a UCUM (Unified Code for Unit of Message) code.
I started looking into libraries that could assist in doing this, but ran into a problem before I got too far. Many of the “units” we have for dosage units in the PIH EMR (and i suspect in many other implementations) are not valid units under UCUM… for instance things like “tablet” or “vial”, which really are “dosage forms”, not “units” (see the explanation here: http://www.healthintersections.com.au/?p=592)
Thoughts on how we want to support this? It seems like ideally we should restrict our dosage units to “true” units, so we could map them to valid UCUM codes, but I suspect that ship has already sailed. Could we used some sort of SNOMED based mapping?