Coding

Base StructureDefinition for Coding Type: A reference to a code defined by a terminology system.

Complex data type in FHIR R4. Maturity: Not stated.

Elements

Element	Type	Cardinality	Description
id	string	0..1	Unique id for inter-element referencing
extension	Extension	0..*	Additional content defined by implementations
system	uri	0..1	Identity of the terminology system
version	string	0..1	Version of the system - if relevant
code	code	0..1	Symbol in syntax defined by the system
display	string	0..1	Representation defined by the system
userSelected	boolean	0..1	If this coding was chosen directly by the user

Reference

Official FHIR R4 specification: Coding.