What is the rationale for drawing labs directly from the vein rather than from the IV or saline lock?When I did clinicals, most patients in the hospital had labs drawn at least once a day. Policy was to have the lab come up and draw the sample from a vein, of course meaning that the patient had to get poked each and every day. The only exception was if a patient had a central line that had been approved for draws (like a port-a-cath) then the nurse could do it.I've never understood why we can't take a sample from the IV in the left AC, but can use a new stick in the right AC to draw one. Is this policy at your facility? What is the rationale?