Smoking Status Observation
In FHIR STU3 standard, Observation resource is designed as a type of event resource describing, measurements and simple assertions made about a patient, device or other subject. For smoking status, we are using this resource.
Smoking Status Observation API return fields including Status (The status code), Category (Classification of type of observation), Code (Type of observation), subject(patient), Issued (date and time of the observation), Value and encounter (Healthcare event).
Based on:
http://hl7.org/fhir/us/core/StructureDefinition/us-core-smokingstatus