This is the ValueSet that contains all the codes in Servicerequest OrderDetail Parameter Code (http://hl7.org/fhir/ValueSet/servicerequest-orderdetail-parameter-code) and Servicerequest OrderDetail Parameter Code (http://hl7.org/fhir/ValueSet/servicerequest-orderdetail-parameter-code). E.g. what you have to deal with if you get resources containing codes in either of them