WASHINGTON — When deciding how much blood to set aside for war, the U.S. military uses a simple equation: It predicts the number of fallen soldiers, then multiplies by four.
It's an inexact science. For the 1991 Persian Gulf War, about 100,000 pints rotated through military blood inventories. Only about 2,000 were used — and many of those for civilians and Iraqi fighters.
U.S. military planners are preparing for the worst in the current Iraq conflict. Casualty estimates for the offensive are classified, but blood reserves have grown significantly in recent weeks.
"This is a lot different" than Operation Desert Storm, said Army Col. Michael Fitzpatrick, director of the Armed Services Blood Program Office. "We're talking about . . . going into Baghdad."
About 24,000 liquid pints were shipped to parts of Asia and the Middle East through mid-February, the Army reported. The inventory was to have expanded as war became imminent.
In addition, civilian blood banks recently signed contracts and promised to sell blood to the military, for about $175 per pint, if government supplies dwindle.
"We'll support them however they deem it necessary," said American Red Cross spokeswoman Lesly Hallman.
Another contractor, America's Blood Centers, picked six cities — Dallas; Denver; Sacramento, Calif.; Tampa, Fla.; Phoenix; and Davenport, Iowa — where local blood donations could be rushed to military transports. Spokeswoman Brooke Thaler acknowledged some concern about civilian shortages. "But in war times," she said, "collections are usually up."
Military officials expressed confidence that the blood distribution network would work well, despite some recent criticisms. "Once you get it going, it's like any other distribution system," Fitzpatrick said.
In 2001, a government audit identified weak spots. It concluded that much of the blood network did not maintain frozen inventories adequate for war. Auditors also found some segments of the network lacked mobilization plans to "clearly define actions needed" in the event of a war.
The auditors urged testing and replacement of expired red blood cell inventories, improved action plans and more training. Military officials said system flaws have been fixed or are being addressed.
Other factors, meanwhile, have affected blood operations. About 18 percent of military personnel cannot donate because their service in Europe raises a risk that their blood is tainted by Creutzfeldt-Jakob disease, the human form of mad-cow disease. And because the military abides by Food and Drug Administration regulations, donations are subject to a growing menu of tests for HIV, West Nile, hepatitis and other diseases.
The current blood delivery system starts with 21 collection centers, mostly at U.S. military bases. Donations are tested for infectious diseases, identified by type, labeled and shipped to one of two distribution hubs.
For the Iraq war, the hub is the Armed Services Whole Blood Processing Laboratory at McGuire Air Force Base in New Jersey. Blood arrives, packed in ice, via express-mail jet or truck. Lab workers test blood temperatures and confirm blood types.
From there, the blood is packed onto Air Force planes headed overseas. The cargo is often accompanied by drugs, bandages and other medical supplies. Delivered to a "transshipment center," blood is then forwarded to surgical teams near battle sites, to field hospitals or to ships that treat the wounded.