Mansfield's experience with MC4 compares to Army Master Sgt. Wynton Hodges' tale of using the system as both medic and patient. In 2006, he was trained as a medic to use Motorola's MC70 and Hewlett-Packard's Ipaq handheld computers to gather injury data in the battlefield in Iraq.

"You can imagine what it must have been like 20 years ago if a doctor had to rely on an injured patient to give their own medical history," Hodges said. "Now we have a system that allows us to see first hand what type of treatment was received" moments ago as well as long in the past.

The value of the system became evident to Hodges when he was on a mission in Iraq one day and broke an ankle. All the data from that treatment was electronically recorded, and became invaluable a year later when he was stateside and examined for leg pain that eventually turned out to be a blood-related ailment unrelated to the ankle injury.

"What was key for me was that over a year later, I couldn't possibly remember all the procedures I had gone through as an injured soldier, but I had the electronic database," he said.

Hodges said concerns about the privacy of his electronic medical records "don't worry me at all, because only certain people have access to the records and there are a lot of safeguards."

The military's investment is well worth the benefits in greater efficiencies in care, but also in terms of giving soldiers and other military personnel an accurate record to use years later, Steen said. With good medical records, a veteran could obtain care under veteran's benefits that he or she might otherwise have to pay for out-of-pocket or through another insurance plan, he added.

After the Gulf War in the 1990s, Congress and then-President Clinton in 1997 laid out plans for a medical tracking system for military personnel on the battlefield, which led to the creation of MC4. The program was in response to thousands of Gulf War service members who returned without proof of combat-related injuries and illnesses, resulting in loss of benefits, according to MC4's Web site.

Steen said that MC4's annual operations cost is US$10 million a year, which includes support to users in the field and to maintain hardware and software. As the program expands, that cost will increase, he said. Steen could not provide a figure for the military's capital investment in purchasing equipment, which could be US$10 million for 26,000 pieces of hardware at a minimum of US$400 apiece, the minimum cost of a typical handheld computer without many custom features.

MC4 has managed to control its costs by using commercially available hardware, as well as software provided free in a US Department of Defense program that allows sharing of health care software already being used at Walter Reed Army Hospital in Washington but tailored for battlefield uses, Steen added.