Tubes of testing-in-process donated blood are visible in the lab at LifeSource Blood Services January 16, 2003 in Glenview, Illinois. (Photo by Tim Boyle/Getty Images) BETHESDA, Md. - The American Association of Blood Banks is pleading for blood donations after revealing the country is in short supply of the fluid."This is the worst shortage I've experienced since I've been in this in this line of work," AABB's Chief Medical Officer Dr.