Welcome  to  public  health  moment from  the  University  of  Minnesota. Only  37%  of  Americans  are  eligible  to  donate  blood, many  fewer  than  previous  estimates. That's  according  to  a  study  co  authored  by  Bill  Riley, a  health  care  management professor  at  the  University  of  Minnesota. What  we've  been  able  to  establish  is that  there  is  about  63  million less  eligible  blood  donors  than  what has  been  previously  used  in  blood  donor  calculations. The  public  should  care  because  all  of  us  need  to  have the  assurance  the  safe  blood will  be  available  when  we  need  it, especially  at  the  times  when  it  is  least  expected. Riley  says  that  the  conventional  method for  estimating  the  number  of eligible  blood  donors  used  age  as  the  only  criterion. But  in  reality,  a  number  of other  factors  can  lead  to  ineligibility, such  as  high  risk  sexual  behavior, chronic  health  conditions,  travel  to  foreign  countries. It's  been  well  known  that  there are  approximately  31  different, what  are  called  exclusionary  factors  that would  make  person  ineligible  to  donate  blood. Most  of  those  factors  are  to protect  the  recipient  of  the  blood  donation. However,  some  of  those  exclusionary  factors  are protecting  the  donor  with  another  public  health  moment. I'm  John  Finnegan.