I did that and the hospital changed me $2,000 I had to pay. The doctor said in the old days they would just take my blood and dump it themselves but now they have to follow rules and they had to call a blood collection service to come to the hospital and do it.
I was so pissed off because it took 6 hours to take a liter of blood out and replace it with saline water. I went home the next day and drained a liter of blood myself in the shower. Only problem is I’m not good at it so I punctured several arteries several times before the full liter was out, I used a liter sized protein shaker to drain the blood into then washed it down the shower drain.