Hundreds of patients who depend on a blood-derived drug to prevent life-threatening infections are struggling to obtain it because of a change in Medicare financing, prompting top blood specialists to declare a crisis.

Some patients say they're months overdue for crucial infusions of immune globulin (search), as Medicare cuts prompt doctors to stop offering the pricey drug and send them to seek hospital care instead. Ultimately the fallout could reach beyond Medicare recipients, because it comes as hospitals fear their own supply system is increasingly fragile.

Last month, the government's blood advisers urged Health and Human Services Secretary Mike Leavitt (search) to declare a public health emergency, a step that would let Medicare increase doctors' payments for intravenous immune globulin, or IVIG (search). Leavitt is reviewing the recommendation.

"We realize this is an important health care issue for patients who rely on IVIG," said HHS spokesman Bill Hall. "We're not going to sit on this for months."

In the meantime, Medicare patients like Linda Swain of Irving, Texas, are desperately looking for hospitals to provide the $3,000 to $5,000 treatment they once got in doctors' offices. Swain has a type of primary immunodeficiency, genetic disorders that disable the immune system. Monthly IVIG restores some of that immunity. But Swain's last treatment was March 29, and last week she caught a chest infection.

"No one would take chemotherapy away from a cancer patient," said an angry Swain, 57, who calls her therapy just as crucial to survival. "We should be able to get our treatment."

Hospital reimbursement hasn't dropped. But germ-prone hospitals aren't the safest place to treat immune-weakened patients. And tightening national supplies may make them reluctant, or unable, to take on many new patients anyway, said Erin Fox of the University of Utah's Drug Information Service, which tracks potential medication shortages for hospital pharmacists.

"It's not a true shortage yet," Fox cautioned, because hospitals still get supplies. But they're paying more, and sometimes waiting for shipments or receiving different brands than were ordered, a problem for patients who tolerate only certain formulations of the side effect-prone drug.

"It's a scary situation," she said. "We know more patients are being shifted to inpatient because of reimbursement rules. But allocations haven't changed. We can't buy any more extra."

Immune globulin is a mixture of antibodies, infection-fighting proteins that healthy people normally have in their bloodstream. Given intravenously, its main use is for many of the 50,000 Americans who suffer primary immunodeficiency, 7,000 of whom receive Medicare.

But IVIG also is used to treat a growing number of other disorders, some as a proven treatment and others experimentally. Indeed, the industry says it has increased production by 80 percent since 1998 to keep pace with increasing demand.

IVIG is difficult to make, because it's culled from human plasma, the liquid part of blood, taken from thousands of donors. There are only a few manufacturers, and prices are rising.

In January, the Medicare Modernization Act required a reduction in reimbursement for IVIG given in doctors' offices. Rather than reimbursing based on average wholesale price, Medicare now uses average sales prices, a lower figure because it includes good deals for big purchasers and figures cheaper brands together with pricier ones.

The change dropped doctors' reimbursements from $66 per gram of IVIG to roughly $39 a gram for powdered brands and $56 for liquid ones.

The cuts add up considering the average infusion is 30 to 50 grams, said Michelle Vogel of the Immune Deficiency Foundation, which has logged 300 phone calls from immunodeficient patients alone with problems finding care.

Today's cheapest powdered brand costs $44 a gram, and prices from so-called secondary distributors can reach $90 a gram, said Patrick Schmidt of FFF Enterprises, the largest IVIG distributor, noting that Medicare based the reimbursements on last year's prices.

Payment for administering the three- to eight-hour infusions dropped 15 percent, too, said the American Academy of Allergy, Asthma and Immunology (search), which last week said the cuts were making many physicians abandon the therapy.

Hospital reimbursement, in contrast, remains at about $80 a gram.

Medicare officials say they're concerned about IVIG access and have been meeting with patient, doctor and industry groups about potential remedies, but the law precludes easy fixes.

"What's unclear is whether the problem patients are saying they're having ... is based on supply only, reimbursement issues only or a combination," said HHS' Hall.