It would not bother me if you were a vampire. The last three times I've tried to donate blood they have not wanted it (a few years ago, I ate the wrong medication, the next time (when I was no longer on any meds) my iron was too low, and most recently I wasn't allowed because I had visited a malaria infested area less than six months prior) and the last time I tried, the cute nurse told me that I could at least feel safe against vampires.