That still sounds like a subset of medical testing to me, where you're using the patient as your test equipment and ignoring anything the patient cannot sense d

That still sounds like a subset of medical testing to me, where you're using the patient as your test equipment and ignoring anything the patient cannot sense directly (or fails to report). Perhaps you don't call the results of medical tests "symptoms", but to me this is an insignificant distinction. Either way we're talking about an observable result of some underlying condition; only the means of observation varies. Jargon aside, this approach still means waiting until after the condition has already affected the patient's quality of life, and perhaps beyond the point where it can be treated effectively, when it could have been treated and perhaps even cured before any symptoms manifested.