Perhaps your doctor first reviewed your past medical record to see if your routine labs were current. If your labs are recent, up-to-date and of normal values they may rely on those rather than ordering new labs. But once you say you have symptoms, a doctor will often order many labs, imaging, etc. to determine a possible cause. There's little point in a doctor ordering a bunch of labs if you don't have any signs or symptoms. I always say if you give a doctor a reason to dig deeper and pay them enough money, they will likely find something wrong with a person.