Quote Originally Posted by Rock_Flock_of_Five View Post
Of course.

As all blood donations get screened anyway, it's just a self-regulating way (the donor's) of avoiding blood donations being unnecessarily futile by being screened and rejected.
Yes they are screened, but Hiv and the aids virus can take a long time to show up in tests, and there is only so long you can keep blood, so there is a big chance that mistakes can be made.