See Zulip chat:

https://chat.fhir.org/#narrow/stream/103-Orders-and.20Observation.20WG/subject/ReferenceRange.20value.20set.20-.20type.2Fmeaning

propose adding a new value of "non-critical" to

http://build.fhir.org/valueset-referencerange-meaning.html

pending a suitable definition.