I have never weighed enough to give blood, but am registered as an organ and tissue donor. I have also informed my family of my wishes (that I wish to donate ALL of my organs and tissues...whatever is needed).
If you're in Michigan it's real easy to register. You can do it online (@ Michigan.gov). It only takes a few seconds and they send you a "heart" to put on your license.
THANKS to all who "give the gift of life"!