I worked in a urology office for 13 years. One of the things some of the male patients will do is bank their own blood for some of the procedures performed . It is called autologous blood donation. I was having a bad day one day and it wasn't until one of the docs called it to my attention, but I had typed "oncologist" blood. Was my face (and fingers) red.

haha! I'll bet! There was a patient who I used to draw regularly. She'd do autologous donations in case of accident and so forth. Since blood has a shelf life before expiring, she'd come in every three months or so. She was a quite easy draw since the AC had the perfect amount of scarring from prior draws.
(I did phlebotomy long before I ever did MT work,; one could say I have led a very interesting life)