Observation and a suggestion:
First, the issue of
who can diagnose is not quite as thorny and confusing as
what a diagnosis is.
In all seriousness, there are a number of people interested in the "philosophy of medicine," and the topic of what constitutes a diagnosis is a healthy area of discussion. Even
ER doctors discuss this. Historians of medicine are also quick to point out the shifting uses of the term over the centuries, as well as shifting bases for diagnosing. One thing I
haven't heard stated, however, is that "only physicians can diagnose." On the contrary...
[A]lthough diagnosis ordinarily has medical connotations, this is not essential, for the term involves activities by no means unique to medicine. Although we may think of diagnosis as the identification of disease, such usage is far too narrow.
Lester S. King
I.e. diagnosis is a human process, and should not be thought of as limited to the mythical scientist-physician. Instead, it is an act of pattern recognition, and active evidence collection, based in innumerable cultural and conceptual biases. And just like a lot of things that all humans do, it's often messy, and we don't talk about the process in public much!
So here is my proposal -
stop using the words diagnosis/diagnosing/diagnostic. Instead, simply say what is going on!
With this method, controversial statements are avoided, and clarity is supported. For example, instead of "I diagnosed an MI," instead say "He was complaining of chest pain, and the ECG showed a STEMI-pattern." Or instead of "I diagnosed CHF," instead state "He was hypoxic, and my initial exam found rales and pronounced JVD." Both of these statements could be made by a medic or doctor, and both contain far more information if the root "diagnos-" is avoided.
Forgive me an additional extended quotation, but I particularly like this one. Understand that Dr King is a pathologist interested in the the medical philospohy of the 1700s and early 1800s. Why, then, does it seem to apply so well to this discussion?
"Scientific medicine lies not in formidable apparatus nor the myriads of available tests, nor in overflowing libraries, but in that stil small voice that I call critical judgment. This voice asks the important questions: 'Do you see a pattern clearly? How good is your evidence? How sound is your reasoning? Can you support your inferences with the means at your disposal? What are the alternatives? What hangs on your decision?' This voice, I believe, goes to the heart of scientific medicine. It has been speaking throughout the ages, but physicians do not always listen. And those who do not listen are empirics, regardless of the technical facilities at their command."
Lester S. King
(N.B. "empirics" is another way to say "technician.)