H1N1 fears are now spreading to the nation's blood supply.

Blood banks are turning away anyone who show signs of sickness.

And with the spread of H1N1, blood collectors say the pressure is on to be more aware.

Donated blood is not screened for seasonal flu or H1N1 because it's difficult to detect in blood

But if you are the recipient of blood from someone with H1N1, could you end up with the virus?
Doctors say the chances of that happening are very low.

"It's very difficult to say that someone got the flu via transfusion or whether they got it as part of the normal progression of the flu through the population," says Dr. Timothy Hilbert of NYU's Langone Medical Center.

If donors get sick after donating, they're asked to call so their blood won't be used.