http://hl7.org/fhir/StructureDefinition/Quantity|4.0.1

Base StructureDefinition for Quantity Type: A measured amount (or an amount that can potentially be measured). Note that measured amounts include amounts that are not precisely quantified, including amounts involving arbitrary units and floating currencies.
Base: http://hl7.org/fhir/StructureDefinition/Element4.0.1, 5.0.0, 4.0.1
Type: Quantity (a.k.a: http://hl7.org/fhir/StructureDefinition/Quantity)
Type dependencies: 5
Elements
code: code
comparator: code
extension: Extension
system: uri
unit: string
value: decimal