Phone: 612-624-5551
24-hr number: 612-293-0831

Advanced Search

This is an archived story; this page is not actively maintained. Some or all of the links within or related to this story may no longer work.

For the latest University of Minnesota news, visit Discover.


A woman in the process of giving blood at a blood bank, with a man tapping a vein in her arm

About 111 million Americans are eligible to donate blood, approximately 66 million fewer than originally believed.

Blood donor pool shrinking

Only 37 percent of Americans are qualified to donate, according to U study

February 5, 2008

Estimates of the number of Americans eligible to donate blood are off by as much as one-third, according to new research from the University of Minnesota.

Only 37 percent of Americans are considered acceptable donors, although it has long been believed that 60 percent were eligible, say the study authors in Transfusion, the journal of the American Association of Blood Banks. In actual numbers, about 111 million people are eligible to donate, 66 million fewer than originally believed.

The pool of potential blood donors traditionally has been calculated based on the population from ages 18 to 65. But many of those people are being screened out because of high-risk behavior, disease, medications, or travel to other countries.

"The rules were created to ensure that the blood supply is safe, but they also make it tougher for blood banks to meet their goals," says School of Public Health associate professor William Riley, one of the study's authors.

Riley, along with co-researcher Jeffrey McCullough, of the Medical School, used the criteria of the American Association of Blood Banks to determine who would be eligible. They estimate that about 183 million Americans would be excluded by current rules.

"The rules were created to ensure that the blood supply is safe, but they also make it tougher for blood banks to meet their goals," says William Riley.

That has broad implications for blood supply in the future. Blood transfusion has become the most common procedure in hospitals, whereas a decade ago it was only the fifth most common procedure, according to Laura Kaplan, manager of marketing and communications for Twin Cities-based Memorial Blood Centers.

To this point, hospitals in the Twin Cities area have been able to meet their demand, but elsewhere that's not always the case. "Nationwide, there have been surgical cancellations as a result of blood shortages," Kaplan says.

A bit about blood

All blood cells are produced from a small number of stem cells found mostly in the bone marrow. The stem cells work like a blood factory, continually producing new cells.

Blood is categorized by type--A, B, AB and O--and Rh factor, positive or negative. This is important because blood type and Rh factor must be compatible with the type and Rh factor of the blood recipient.

O-positive is the most common type of blood and AB-negative the least common.

She adds that blood banks have to deal with seasonal shortages--like around the winter holidays when "people are busy doing other things, and then the blood supply plummets"--and being adequately prepared for large-scale disasters. "It's a very delicate balance," she says.

Riley says the research team will determine further who is eligible to donate and pass that valuable information on to blood banks.

"Blood collection organizations can develop recruitment strategies to encourage those who don't currently donate to consider doing so," he says. "These strategies are essential because the size of the eligible donor population is projected to decrease over the next decade."

Reprinted from Advances, fall 2007, a publication from the University of Minnesota's School of Public Health.

To hear a Public Health Moment on this study, visit SPH Moment.

To find out more about donating blood through Memorial Blood Centers, visit MBC or call 1-888-GIVE-BLD.