The New York Blood Center issued an emergency appeal for donations Monday, just a week after the American Red Cross made a similar request.
"This really goes from Boston to L.A. and hits the heartland," said Jacquelyn Fredrick, chief operating officer for the American Red Cross blood services.
Twenty-five of the 37 regional blood centers run by the national Red Cross had less than one day's supply of Type O blood - known as the universal donor type - on hand a week after the organization issued an emergency appeal, Fredrick said. Among the most severely affected areas are Los Angeles; Philadelphia; Baltimore; Washington, D.C.; Detroit; Nashville, Tenn., and Columbia, S.C.
The New York center, which operates independently of the American Red Cross, had less than a two-day supply of Type O blood Monday.
"We like to have about a five-day supply," center spokeswoman Linda Levi said.
In Toledo, Ohio, where the Red Cross called 135 people asking them to donate, 75 declined because they were suffering from the flu or another illness, Fredrick said.
At a Peoria, Ill., drive to collect blood platelets needed by cancer patients, 24 of 34 scheduled donors canceled their appointments because of illness.
The shortage highlights a widening gap between blood supply and demand.
"Usage is growing as fast as we can collect more blood because of the aging population and more advanced medical treatments like transplants," Fredrick said. "The blood supply in this country is very fragile. Even in the best of times, we're probably only a day away from a blood shortage."
Donors can call the American Red Cross at 1-800-GIVE-LIFE to schedule an appointment.
To give blood, you must be healthy, at least 17 years old, and weigh at least 110 pounds. Persons who are older than 65 and in good health may sually donate with the approval of the blood bank physician. Healthy donors may give blood as often as every eight weeks.