Diagnostic
The Diagnostic resources are concerned with the process of observing, testing, and diagnosing a patient. Note, once a diagnosis is confirmed, it would be recorded in Condition so that it is part of the historical patient record.
The Observation resource is primarily concerned with recording discrete values, answers, and results such as clinical laboratory data and vital signs while the DiagnosticReport resource typically provides a textual set of information and interpretation after performing a diagnostic service such as a Radiology report or Pathology report.
Click here to see the detailed categorization and full set of resources that fall into this category in the HL7® FHIR® Standard.