Blood: Safety vs. supplies

Conflict: Critics say exclusions and tests to find tainted donations just worsen shortages.

Medicine & Science

December 01, 2003|By David Kohn | David Kohn,SUN STAFF

Is the U.S. blood supply too safe for its own good?

Some safety experts say the government, Red Cross and other blood suppliers have become too cautious, excluding too many donors and adding too many safeguards. The result: Fewer people qualify to give blood, at a time when the supply barely meets the demand.

The debate highlights the growing conflict between blood safety and blood supply. The tension has heated up in recent years as shortages have become more common. Blood bank officials warn that in a crisis, hospitals could run out altogether.

The critics' favorite targets are the so-called "European deferrals." Worried that the human variant of mad cow disease could contaminate the U.S. supply, blood banks here no longer accept blood from anyone who lived in Europe for five years since 1980, or who lived in England for more than three months between 1980 and 1996.

Critics say the exclusion is arbitrary and unscientific.

"There isn't any reason to think that a one-month stay would expose you any less than a three-month stay or a six-month stay. A vegetarian could stay in Europe for 50 years and be a fine blood donor," said University of Pennsylvania medical ethicist Arthur L. Caplan.

Caplan, who until last year served on the U.S. Food and Drug Administration's blood supply advisory committee, says there's no evidence that mad cow disease, formally known as Variant Creutzfeldt-Jakob Disease (vCJD,) can be transmitted via human blood.

Others point out that countries with human mad cow cases provide a good test case. "Britain is collecting blood from an entire population that was exposed to vCJD, and there have been no positives," said blood safety expert Dr. Michael Busch, a professor of laboratory medicine at the University of California, San Francisco.

The deferrals, which took effect in 2002, have excluded at least 5 percent of those who normally give, the FDA says. Many in this group are long-term repeat donors - a group much less likely to carry disease than first-timers, studies show.

But the FDA and the Red Cross argue that uncertainty over how mad cow disease is transmitted makes the exclusion necessary.

"We think the current deferrals for vCJD are appropriate, prudent measures," said Dr. Jay Epstein, director of the FDA Office of Blood Research and Review, which sets blood supply policy. Although vCJD has never been shown to spread via human blood, Epstein notes that a study of sheep found that it was theoretically possible. And the mysterious disease can take years or even decades to appear in its victims, he says.

Epstein points to the transfusion crisis of 20 years ago, when tainted blood infected 20,000 Americans with HIV. At the time, blood suppliers ignored early warnings of a problem; Epstein and others don't want to repeat this mistake.

"In the '80s we were concerned about [keeping] donors. And we ended up with thousands of patients who became infected with HIV through transfusions," said Michigan State University hematologist Dr. John Penner.

More than 40 of Penner's patients suffered that fate. "We had an opportunity to reduce the exposure significantly and we didn't do it. We listened to the economists. Availability is secondary to safety," he said.

But others say the AIDS disaster has made regulators and blood banks too skittish. "The FDA is still feeling the sting from HIV," said Dartmouth Medical School pathologist Dr. Jim AuBuchon. He argues that by reducing the number of donors, the deferrals are likely doing more harm than good.

"The blood supply is very tenuous. Shortages we used to see only during certain holidays are becoming more frequent," said AuBuchon, who also runs the Dartmouth blood bank.

The European deferrals are not the only controversial exclusions. The FDA permanently bars any male who has had even one sexual experience with another male since 1977. The ban, put into effect in 1983, before tests for HIV existed, eliminates more than 62,000 donations a year, by an FDA estimate.

"I think it's overkill," said Dr. German LeParc, chief medical officer of the Florida Blood Services and a board member of the American Association of Blood Banks. He recommends a six-month waiting period for men from their last sexual contact with a male. This temporary ban would allow enough time for HIV antibodies to appear in the blood of an infected donor, and thus show up on tests.

Another point of contention is the practice of filtering white cells, known as leukocytes, from donated blood. Over the past decade, many blood banks have begun removing leukocytes, which can cause post-transfusion fevers and other immune reactions in recipients.

Although the FDA has not ordered their removal, the Red Cross, which accounts for half the nation's blood supply, filters leukocytes from more than 90 percent of its blood. Independent blood banks, which collect the other half of the blood supply, filter about 70 percent of their blood.

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