This is the ValueSet that contains all the codes in US Core Clinical Result Observation Category (http://hl7.org/fhir/us/core/ValueSet/us-core-clinical-result-observation-category) and US Core Clinical Result Observation Category (http://hl7.org/fhir/us/core/ValueSet/us-core-clinical-result-observation-category). E.g. what you have to deal with if you get resources containing codes in either of them