17+ Rainbow Blood Draw. Collecting a predefined set of blood tubes (the “rainbow draw”) is a common but controversial practice in many emergency departments (eds), with limited data to. Web the tests vary depending on what is going on with the patient.

An rdw (red blood cell distribution width) blood test measures how varied your red blood cells are in. Cancer cells shed little bits of dna, called circulating tumor dna,. Web overview what is an rdw (red blood cell distribution width) blood test?