"Diagnosis of exclusion"

A zillion years of medical and graduate school, and nearly three years of residency, and I still don't understand what it means when people say that such-and-such is a diagnosis of exclusion. Any diagnosis is a diagnosis of exclusion!

Often, I think, people use that phrase as a retelling of the widespread myth that psychopathologies can't be diagnosed through testing. ("Anxiety is a diagnosis of exclusion.") Or a claim that only laboratory tests or imaging matter, not the history or physical. ("Hepatorenal syndrome is a diagnosis of exclusion.")

The next time someone calls a diagnosis a D of E, by gum, I'm going to ask them just what they mean.


  1. A disease which is referred to as a "D of E" is one for which no affirmative test exists. Given a patient with a certain history and physical exam, one can establish a differential diagnosis. For most of the diagnoses on that list there will be a set of criteria that can be met in order to give the patient that diagnosis. For a "diagnosis of exclusion" there is no such set of criteria. The only thing that can be done is to exclude everything else on the differential and thus leave you with the final diagnosis.

  2. Hi, Evan! Thanks for dropping by...

    Every diagnosis has an "affirmative test." Otherwise you wouldn't be choosing it as the diagnosis. Now, the definition of a diagnostic test is a lot broader than most people think. Clinical reasoning is as much a diagnostic test as is laboratory tests or imaging - in fact (this is something else people fail to realize) all three of these have their own operating characteristics.

    My claim, I think, is that there is *no such thing* as a D of E, because there is no diagnosis that lacks a test. Prove me wrong...

    Shanah tovah!