It was really neat, too, 'cause they asked me to do a double red cell donation. They normally don't do that for folks with Type A blood, but apparently the blood supply is pretty low. (Go give blood, if you're eligible.) After they explained what it was, I said that it sounded fun.
What they do is take out twice as much red blood cells as they do when you donate a pint of whole blood. But it would probably be bad news to simply remove two pints of fluid from your body, so they remove the blood and separate the red cells from the plasma. They keep the red cells and pump the plasma back into you. That was pretty fun. They also pump some saline into you to help keep you hydrated. They told me that I actually left more hydrated than I was when I came, 'cause they give me back all my plasma, take 400 mL of red cells, and give me 500 mL of saline. That's pretty neat. In order to do the whole procedure, they go through two rounds of removing blood, separating it, and returning plasma and saline. The extraction and return all takes place through the same needle. I have to wait 4 months, instead of 2, before I can donate again.
The neatest part of the whole thing was feeling the plasma returned into my body. Since it's about 98 degrees inside my body, the plasma had some time to cool down when it was sitting in a bag (it looks like Mountain Dew) at room temperature. So, when it was returned to my body, I could feel it's coolness flowing down my side towards my leg before it warmed up to be the same temperature as the rest of my body. That was really neat. There was also a strangeish taste in the back of my mouth for a few minutes, but it went away before I could decide what it tasted like.
Anyway, I love giving blood. And yesterday's bloodletting experience was lots more fun than usual! I'm looking forward to my visit in January -- maybe they'll want to do a double red cell donation again.