Having watched True Blood, both seasons pretty much back to back, I was left with a question or two about the "TruBlood" (artificial blood substitute) product featured in the show. First, was it a product of medical research, or was it designed specifically as an alternate food source for vampires? Personally, it makes more sense to me if the former is true. In that case, it wouldn't have been packaged in bottles until after vampires came out in public.
Next, why is it available in all human blood type varieties, rather than just O-negative? If it's the result of medical research, it would make more sense only to make O-negative rather than all varieties, since it's the universal donor. The varieties make more sense if it were made directly for vampires, but then I'd expect it to taste a bit better to them.
Mokalus of Borg
PS - I realise it's just fiction.
PPS - I'm just trying to fill in the blanks and make sure it's internally consistent.