I think the physician should never make an immediate diagnosis of a disorder. The physician should only come up with possible diagnostics and then do further tests like blood tests to confirm and later come up with a conclusion. Another reason as to why they should not make immediate diagnosis of a disorder is because the sample being used might have been contaminated.
Just one urine test is not enough to determine if the patient is disturbed or not. It would be wrong if the doctor made a diagnosis just because of this test. Ideally, the doctor should order other physical tests and from their results, assess the patient's history and come to a conclusion on whether the patient has a health problem or not.
