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 c9ad2e8a-05d1-4fde-9d98-460e1ab4dcf1-1496
This code system http://hl7.org/fhir/comparison/CodeSystem/c9ad2e8a-05d1-4fde-9d98-460e1ab4dcf1-1496 defines codes, but no codes are represented here