What does it mean when we say Probable Diagnosis in a report?

Probable diagnosis in a report implies a high degree of certainty with regards to a diagnosis.  There is however, a little room left for doubt and other possibilities.  This is a word often used in the impression or conclusion of the report.

Words like “probable” give a degree of certainty of a diagnosis

There are other words that radiologists use to provide a probability of a diagnosis being present.  Others may be: may represent, possibly, likely, concerning for etc.  Other times radiologists may provide a set of possible diagnosis called a differential diagnosis.

Certainty of a diagnosis can increase when combining clinical information and further testing

The certainty of a diagnosis can increase if the clinical history supports what is found on imaging.  Further laboratory testing and imaging may also provide more confidence to a diagnosis that a radiologist raises in a report.

Example of a probable diagnosis.

An example may be for a liver mass.  Many liver masses can have some overlap in appearance on imaging.  A vascular liver mass in a young women who takes birth control pills may be a probable adenoma but there are other masses which can have a similar appearance.

Another example of a probable diagnosis in a report may be concerning a thick walled gallbladder with stones.  While in the setting of right upper quadrant pain, this may represent represent probable cholecystitis or inflamed gallbladder, there are other possibilities.  This can represent a thickened gallbladder from other causes like liver disease or heart failure.   The diagnosis can be made certain from appropriate clinical symptoms and further testing with ultrasound.

A probable diagnosis of cancer can sometimes be made on a CT. The appearance of cancer on a CT needs to be confirmed with biopsy.  There are also other conditions that can look like cancer on a CT.  The radiologist may use words like highly concerning or probable instead of saying there is cancer.

Radiologists sometimes use words like probable diagnosis in reports to convey a high degree of certainty but not 100%.  The confidence can reach 100% for a diagnosis when combined with the clinical presentation and further testing.

Radiology imaging tests are a piece of the workup of a condition or symptom.  Everything must be combined to reach a diagnosis. The radiologist will often use words to convey the degree of certainty of a diagnosis.  This will help the referring physician understand how certain a diagnosis is.