I'm AB Positive (or at least that's what my dog tags used to say) so I'm able to receive blood from any donor, but other AB Positive patients (only 3% of the population) are the only people who can use my blood. That makes my donation somewhat useless, seeing as AB Positive patients can just use whatever bag o' blood is sitting on the shelf and nearing its expiration date. But I'd give in the event of a catastrophe.
My daughter received 2 pints of blood while she was hospitalized last month, so thanks to everyone who donates!
P.S. I'm an organ donor, but I'm afraid my liver won't be of much use to anyone.