Blood donation.
Rodell
M B
MB
D001782:Blood Donors / Q000706:statistics & numerical data*; D015658:HIV Infections / Q000453:epidemiology*; D015497:HIV-1; D006526:Hepatitis C / Q000453:epidemiology*; D006801:Humans; D014481:United States / Q000453:epidemiology; D014838:Volunteers / Q000706:statistics & numerical data*