As part of the v2-to-FHIR projects we are encountering a small number of scenarios where a coded concept in the v2 message (a field with CE, CWE, etc) maps to a FHIR element using the code datatype and a value set with a required binding (for example AllergyIntolerance.category or .criticality). When the v2 value set is larger than the FHIR value set there may be a many-to-one mapping which results in the loss of information.

We are requesting a general extension that can be applied to the code data type (and maybe other coded data types but not just to resource specific elements) which can be used to convey the original coded concept. We would like to propose:

name: originalCodeableConcept or originalCodedConcept (something along these lines)

datatype: CodeableConcept