Dwindling blood supplies have prompted the American Red Cross to issue an emergency call to donors. The Red Cross announced Monday that its blood supply has reached emergency levels, with 50,000 fewer donations nationwide than expected this month. The shortfall leaves the organization with half of the readily available blood products on-hand compared with this time last year, said Nancy Martin, the senior account manager for American Red Cross Blood Services’ Southern Region.“Usually we don’t get this low until after July 4.