[A Navy Vet]

"Is that A negative? I forgot."

Not sure without Googling, but I believe O+ to be the universal blood type. I'm AB-, the rarest. I often think of storing a supply of my type in a local blood bank.

[Vigilanteman]

Thanks. There is a nice table about halfway down on this site.

Basically, AB+ is the universal recipient so can take blood from anybody. O- is the universal donor so can donate to anyone. A- (which I have), and B- are the next most useful blood types for donations since the negative types can donate to either - or + of the same blood type or either AB, but not O. O+ can only donate to any positive blood type.

So as AB negative, you actually have the choice of four other blood types as sources of donations, but can only donate to AB- or AB+.