This is the CodeSystem that contains all the codes in AllergyIntoleranceCertainty (http://terminology.hl7.org/CodeSystem/reaction-event-certainty) and AllergyIntoleranceCertainty (http://terminology.hl7.org/CodeSystem/reaction-event-certainty). E.g. what you have to deal with if you get resources containing codes in either of them
Generated Narrative: CodeSystem 0fe243fb-0325-42eb-9949-7980a81f5112-791
This code system http://hl7.org/fhir/comparison/CodeSystem/0fe243fb-0325-42eb-9949-7980a81f5112-791 defines codes, but no codes are represented here