This is the CodeSystem that contains all the codes in ChargeItemCode (http://terminology.hl7.org/CodeSystem/chargeitem-billingcodes) and ChargeItemCode (http://terminology.hl7.org/CodeSystem/chargeitem-billingcodes). E.g. what you have to deal with if you get resources containing codes in either of them
Generated Narrative: CodeSystem 21d0d52d-6932-4516-ad29-944d62abcb69-680
This code system http://hl7.org/fhir/comparison/CodeSystem/21d0d52d-6932-4516-ad29-944d62abcb69-680
defines codes, but no codes are represented here