They can tell you something is different, or out of the normal range, they don't give you the real cause of the problem though. This is left to the doctor who w

They can tell you something is different, or out of the normal range, they don't give you the real cause of the problem though. This is left to the doctor who will take into account age, gender, medical history, as well as the fuzzy description of the problem from the patient. Then they'll give you some medication and hope that it heals in a few days, if not, then re-assess and do more trial and error diagnostics and medications (which can go on for months, even years). If we had technology that could monitor internal changes on a real time basis though, then the face of medicine would change forever.