Where are you located and what, precisely, do these medical tests entail? What biochemical mechanisms do they look at for accurate diagnoses? From my observati

Where are you located and what, precisely, do these medical tests entail? What biochemical mechanisms do they look at for accurate diagnoses? From my observation of psychological testing and diagnosis on the research side in the US, its a shit show. Most of it is self reporting and questionnaires which don't actually tell us anything about underlying mechanisms. Its just a bunch of symptom check boxes.