Mods, please forgive the resurrection of a zombie thread, especially one started by, well… nm, but I really wanted to contribute.
Since a lot of talk has been related to phlebotomy and drawing blood into tube, I wanted to relay a color story. Blood in a specimen tube, once centrifuged, is generally separated into three parts. The actual red blood cells (which make the blood red colored whether it’s arterial or venous), the buffy coat (a thin layer of white blood cells and platelets), and the plasma/serum (the liquid part of the blood that is used for transportation of the blood cells, blood protein, etc…).
Although the blood is always red in different shades, there are certain types of medications that can make the plasma/serum a variety of colors. This is in my experience, I’m not gonna dig up a bunch of cites (sorry, bad etiquette once again). These colors can range from green to even a purple. The purple patient sent me running to a PDR to try and find out what med the patient was on to cause this. I couldn’t actually find the source, but trust me, the plasma was purple!
And there’s always the issue of lipemia and hemolysis. The latter caused by internal blood cells lysing or a bad needlestick draw, the former caused by eating too many cheeseburgers before a blood draw. So please, skip the McDonalds visits before donating blood. Thank you for donating, but you are actually passing on the cholesterol!