Stream: IG creation
Topic: MustSupport on the data elements of a complex data type
Thomas Zhou (Apr 06 2022 at 21:23):
Can the Must Support (MS) tag be applied to the data elements of a complex data type?
I have some thoughts about it. But I do need your gurus’ guidance.
The ElementDefinition presents MS as an attribute of the BackBone element.
The data elements of a complex data type are not the BackBone type.
Therefore, they shall not be eligible for the MS tag.
Eric Haas (Apr 06 2022 at 21:33):
We document this in US Core here
Lloyd McKenzie (Apr 06 2022 at 21:37):
MustSupport is a characteristic of ElementDefinition, which applies to all elements. It's certainly possible to mark elements within a backbone element as 'must support'.
Thomas Zhou (Apr 07 2022 at 18:23):
Should MustSupport also be applied to the elements of an independent complex data type that does not connect to any FHIR resources?
Thomas Zhou (Apr 07 2022 at 18:24):
Should MustSupport also be applied to the elements of an independent complex data type that does not connect to any FHIR resources?
Lloyd McKenzie (Apr 07 2022 at 18:31):
mustSupport should be declared on any elements that you expect implementers to support if they comply with your IG. (Though if you reference a profile that has its own mustSupport declarations, you don't need to drill into the descendants to declare those unless you want to add some additional context-specific descendent elements as mustSupport.
Thomas Zhou (Apr 07 2022 at 20:52):
Thank you for such a quick reply and valuable information.
Which one or perhaps both are following best practices in FHIR IG implementation?
- To declare the MustSupport tag to the subelements of an independent data type, then assign the data type to the data elements in FHIR Resources.
- To declare the MS tag to the required subelements displayed in the resources.
Lloyd McKenzie (Apr 07 2022 at 22:02):
If the mustSupport requirements are consistent across multiple uses of a given type, creating a shared profile for the type makes IG maintenance easier and makes clear to implementers that the expectations are consistently shared across all places that reference the profile.
If the requirements aren't consistent, then you'll need to express them inline in the referencing profile.
Thomas Zhou (Apr 08 2022 at 02:20):
Thank you very much for such crystal clear answer!
Last updated: Apr 12 2022 at 19:14 UTC
