Condition
The Condition resource is used to record details about a patient’s problems, diagnoses, or other health matters that are concerning. It is common to capture Conditions during the encounter or visit.
The Condition API returns fields including category (assigned category to the condition), Code (Identification of the condition, problem or diagnosis), clinical status (The clinical status of the condition), Verification Status (Verification status to support clinical status of the condition) and Subject (person who has the condition).
Based on:
http://hl7.org/fhir/us/core/StructureDefinition/us-core-condition