WASHINGTON — In a medical irony, Americans with blood type O — universal donors who can give to anyone — are the least likely to receive a new liver, heart or lung.
That's because their organs are transplanted into patients with all sorts of blood types, extending the wait for type O patients who can only use type O organs.
As a result, very sick liver patients with blood type O are 1 1/2 times more likely to die waiting for a transplant than similar patients with other types, according to statistics from the United Network for Organ Sharing, which runs the nation's transplant system.
"It's inherently unfair," said Dr. Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania Health System. "It doesn't make any sense to penalize them because of a biological accident."
Hoping to rectify the disparity, the network is considering new restrictions on the use of type O organs. The proposal would affect liver transplants, raising the bar for how sick non-O patients must be before they are offered O livers.
The challenge is to balance the needs of individual patients with the goals of a national system. On any given day, experts say, it makes sense to give a type O liver or heart to a very sick patient with blood type A or B, rather than a type O patient who is stable and can wait longer.
"It's very hard to make a decision based on policy of what's best for the whole community when you have a patient in front of you. You want to take care of the sickest patient first," said Dr. Todd Howard, who directs the liver and kidneys transplant programs at Barnes-Jewish Hospital in St. Louis.
As policy makers grapple with the issue, type O patients seem less concerned with fairness, said Howard, who also chairs the network's liver transplant committee.
David Somerville, who is still waiting for a new liver after six years, remembers hearing that his type O blood would hurt his chances, with someone telling him sarcastically, "'Oh lucky you, you're type O,"' he recalled.
"When you look at the statistics, it doesn't seem like it should be right," said Somerville, 51, of Latrobe, Pa., outside Pittsburgh. "But that's what we have to deal with."
This disparity is distinct from the higher-profile dispute over whether to give organs to the sickest patients first, or to those who live nearby. That geographic debate is complicated by politics and economics, because a change in policy could result in some hospitals getting more organs for transplant than others.
In the case of type O patients, the issues are medical and ethical.
The statistics differ by organ, but in each case, people with blood type O wait longer for transplants.
For livers in 1994-96, the typical type 0 patient waited a year and nine days. That's four months longer than those with blood type B and more than five months longer than patients with blood type A, according to statistics from the network's 1997 report on waiting times, the most recent available.
For heart transplants, type O patients wait more than four times as long as patients with AB blood, and more than twice as long as those with A or B.
In the case of kidneys, type O patients face similar disparities, although statistics show that patients with type B blood wait the longest. That's because there are a disproportionate number of black patients waiting for new kidneys, and they are more likely to have type B blood.
For lungs, type O organs are reserved for type O patients, and the disparities are smallest.
Across the board, patients with AB type get organs fastest, because they can accept organs of any blood type.
A recent study in five Southeastern states found that, for certain liver transplant patients, the chances of dying while waiting for a transplant were zero if you had blood type AB.
The chance of dying was 22 percent with blood type B, 35 percent for type A and 50 percent for type O.
The change being considered by the transplant network would affect patients who are in the hospital but do not face imminent death. It would prohibit use of O livers for these patients with blood types A or AB. Patients with blood type B, which is quite rare, could still get O livers.
Even with the policy change, for every one person who gets a new organ, another won't. Last year, 6,012 people died waiting for all types of organs.
Howard said he often feels like he's rearranging deck chairs on the Titanic.
"That's what we're doing all the time," he said. "At least we're keeping the ship balanced while it's going down."