The Dr draws the blood in his office, but he pays the outside lab's fees. He bills the insurance and hopes to get paid enough to cover his cost. If not, then he will bill the patient after the fact. So, the outside lab bills the Dr, not the insurance. So, I post the blood draw and tests ordered on the CMS1500, is that correct? and, mark Box 20 NO, is that correct? thanks in advance for your input! I need to get these claims out!