This is the ValueSet that contains all the codes in US Core Simple Observation Category (http://hl7.org/fhir/us/core/ValueSet/us-core-simple-observation-category) and Observation Category Codes (http://hl7.org/fhir/ValueSet/observation-category). E.g. what you have to deal with if you get resources containing codes in either of them
Generated Narrative: ValueSet a788f7f2-3455-4664-96f2-1ee14e1cc7e9-41
This value set includes codes based on the following rules:
http://hl7.org/fhir/us/core/CodeSystem/us-core-category