This is the CodeSystem that contains all the codes in PHD Observation Categories Code System (http://hl7.org/fhir/uv/phd/CodeSystem/PhdObservationCategories) and PHD Observation Categories Code System (http://hl7.org/fhir/uv/phd/CodeSystem/PhdObservationCategories). E.g. what you have to deal with if you get resources containing codes in either of them
Generated Narrative: CodeSystem f6ddaa79-9eba-41ef-bc36-32278a8883b1-17
This code system http://hl7.org/fhir/comparison/CodeSystem/f6ddaa79-9eba-41ef-bc36-32278a8883b1-17 defines codes, but no codes are represented here