This case-sensitive code system http://hl7.org/fhir/condition-ver-status defines the following codes:
Code
Display
Definition
provisional
Provisional
This is a tentative diagnosis - still a candidate that is under consideration.
differential
Differential
One of a set of potential (and typically mutually exclusive) diagnoses asserted to further guide the diagnostic process and preliminary treatment.
confirmed
Confirmed
There is sufficient diagnostic and/or clinical evidence to treat this as a confirmed condition.
refuted
Refuted
This condition has been ruled out by diagnostic and clinical evidence.
entered-in-error
Entered In Error
The statement was entered in error and is not valid.
unknown
Unknown
The condition status is unknown. Note that "unknown" is a value of last resort and every attempt should be made to provide a meaningful value other than "unknown".