>No, it should be equal.

Okay, what is the consistent testing/diagnostic methodology that accurately measures stress and psychosomatic impact across patients?

Typically it is going to be a diagnosis of exclusion. If you think you're diagnosing someone with stress/psychosomatic causes before comprehensive testing, imaging and/or specialists visit have been done, then you're jumping the gun, and potentially adding further stress to the patient as they try to follow a regimen that has little effect at helping their condition.

I was not aware of the Stanford CFS clinic drama.

Yes, the doctor should explore all possible causes with the patient. Tests can be done, and the doctor can also discuss stress. That is generally how it is done. Quite often in these cases there will be no final diagnosis.

That sounds a lot like a diagnosis of last resort. Especially if the best tool available for measuring stress is a yes/no question to the patient and a 5-question anxiety questionnaire. Hardly definitive evidence of stress/psychosomatic causes, especially if it comes back "negative".

There is no “stress” diagnosis test. It can never be a definitive diagnosis. The patient just needs to consider it.