点击显示 收起
Aug. 1, 2007 – Sixty-six million fewer Americans are eligible to donate blood than previously thought -- cutting the donor pool from 60% to 38% of U.S. residents.
U.S. blood centers have been operating under the assumption that 177 million Americans could give blood. But that's a "gross overestimate," find University of Minnesota researchers Jeffrey McCullough, MD, William Riley, PhD, and colleagues.
That 177 million figure overestimated the actual number of eligible U.S. blood donors -- 111 million -- by 60%.
"The finding that blood donation rates are calculated with a 60% overestimate is a tremendously important piece of scientific knowledge," McCullough tells WebMD. McCullough, professor of transfusion medicine, laboratory medicine, and pathology and director of the biomedical engineering institute at the University of Minnesota, serves as scientific director for the St. Paul Regional Red Cross Blood Service.
There are 31 factors -- ranging from recent tattoos to HIV infection to heart disease -- that either make a person's blood unsafe or make it unsafe for a person to donate blood. Until now, estimates of the U.S. blood-donor pool failed to take these factors into account.
"Ever since the dark days of the AIDS epidemic, blood safety has skyrocketed. But if you look at all the factors you now screen for, nobody had ever thought to add those up," McCullough says.
"The blood-donation community has been so focused on safety and the challenge of securing safe blood, they haven't had the chance to look at the biggest picture of all -- the actual number of eligible donors that are out there," Riley tells WebMD. Riley is associate dean of health care finance and management at the University of Minnesota School of Public Health.
Until now, blood-donation experts saw 60% of Americans as potential blood donors. In reality, only 38% of Americans could give blood if they wanted to.
In one sense, the finding is good news for blood-collection centers. Instead of getting only 81 units of blood per 1,000 eligible donors, they're actually getting 129 units of blood per 1,000 donors.
On the other hand, the new findings mean that blood centers have pretty much reached everybody they can with current efforts. They will have to come up with new ways to motivate people to give blood, says Richard Benjamin, MD, PhD, chief medical officer for the American Red Cross. Benjamin was not involved in the McCullough study.
"We have for some years now been increasingly struggling to recruit sufficient donors. This study really helps us understand why we are having that struggle," Benjamin tells WebMD. "We need to devise new and innovative ways of encouraging donors to give blood."
Or more blood. The average donor gives 1.7 times a year. Just increasing this to two donations a year "would be a major step forward," Benjamin says.
McCullough and Riley say it's time to recruit sophisticated social scientists to come up with ways to get more eligible donors to give blood.
"As the U.S. population ages and the demand for blood increases, if blood banks don't come up with novel approaches, the blood supply will be in real jeopardy," McCullough says.
?
Will blood banks relax their current safety standards so that fewer willing donors will be turned away?
No, Benjamin says. But while he can't think of any current reason for donor deferral that might be excessive, he says that blood centers will be thinking twice before implementing new restrictions.
"It may be time for us to look more closely when we bring in new safety measures that will defer broad swaths of donors who may not actually be at risk," Benjamin says. "We have to ask, 'Can we afford to do that?'"
Benjamin also notes that safety cuts two ways.
"The most dangerous unit of blood is the one we don't have," he says. "Not having blood for someone who needs it is worse than giving someone a unit of blood that carries a 1-in-5 million chance of disease."
But the real bottom-line message from the McCullough study is that eligible blood donors are more important than ever before.
"If you are an eligible blood donor, you are now known to be a minority," Benjamin says. "We strongly encourage eligible donors to step forward and give blood on a regular basis. It is such a precious commodity -- and it is getting harder and harder to get."
The study by Riley, McCullough, and colleagues appears in the July issue of Transfusion.
?