"They don't have any money," said Lynn Bailey, a health care economist in Columbia. "They know how expensive the care is, they don't have any place to go and being hounded by one more bill collector is more than they can bear."

Karl Gorrell, chief financial officer at Trident Health System, which owns Trident Medical Center in North Charleston and Summerville Medical Center, said he's seen a 15 percent rise in recent years in the number of hospital bills that come back undeliverable.

He said there are two reasons for the increase:

For one, he said, many people who come into an ER are in a hurry. They sometimes make mistakes filling out forms.

But he also believes there's a growing percentage of patients who are afraid of getting the hospital bill. "I think it's fair to say that individuals show up in the ER knowing that they're going to end up using us as their primary care provider," Gorrell said. "They may not want to supply us that information."

Sorting through fake names and addresses is just one problem hospitals are dealing with as they see a steady rise in uninsured patients. Those numbers are growing as health care costs rise and become less affordable to people whose employers don't pay for coverage.

Nationwide, some 44 million people are uninsured, according to Census Bureau figures. The state Department of Insurance estimates that 1 in 5 Charleston area residents has no health coverage.

Hospitals say the trend is hurting their pocketbooks.

Through February, the Medical University of South Carolina provided $15.2 million in what's termed charity care. That's an increase of nearly 50 percent over the same period last year, when it provided $10.2 million, according to university financial statements.

Roper St. Francis Healthcare saw a 60 percent increase in charity care last year and is expecting a 50 percent hike this year, said Chief Financial Officer John Steel.

Trident's combined bad debt and charity care has grown by more than 30 percent each of the past two years and appears headed for a similar increase this year. The hospital system is on pace to provide $57 million in uncompensated care in 2004, more than double the amount it provided in 2001.

Trident's Nashville-based parent company, HCA, announced last month that bad debt increased more than 62 percent in the first quarter due to higher numbers of uninsured patients and now equals 11.7 percent of corporate revenues.

Gorrell, Trident's CFO, said hospitals also are dealing with more patients whose insurance plans include high deductibles that force people to bear more of the financial burden.

"The increase in the uninsured and the increase in deductibles have been a much bigger concern over the past 18 months than it ever has been in the past," Gorrell said. "It's a huge concern."

Uninsured patients tend to head to ERs because, of course, they have no family doctor to see. State figures show that in Charleston more than 22 percent of ER patients don't have health coverage.

Tom Rounds, Trident's ER director, said that a lot of the patients come in for simple problems. For instance, he said one patient recently came in because of a bad toothache that required dental care. The ER couldn't do anything for the patient and had to refer him to dental clinics that cater to the indigent.

"We are often the last resort for individuals who don't have the ability to pay for health care services," Rounds said.

Because they can't afford the bill, some uninsured patients put off their medical problems until they get more serious -- and more expensive to treat.

"We're seeing them for more serious issues," Steel said. "I think it's because they're waiting, they're not getting routine primary preventive care, and, frankly, there's more of that population, and there are no other outlets there for them."

Because ERs are required to treat anybody who walks in, regardless of a patient's ability to pay, that's where most of the returned bills are generated.

Paul Weaver, director of hospital patient accounting at MUSC, said he, too, has noted an increase in the number of returned bills over the last couple of years.

Weaver said that in many cases, wrong addresses are a simple matter of the patient moving. In those cases, the Postal Service helps track down patients. Doing so gets far more difficult when there isn't a forwarding address or the address and patient's name are fake.

Weaver said MUSC will spend about a week trying to hunt down such patients and then will forward the bill to a collection agency.

Jay Rickman Jr., vice president of one such agency, Columbia-based Amcol Systems Inc., said that if an address is truly wrong, his agency may never find the patient, and then the hospital chalks up that bill to its bad debt expense.

Rickman said most patients who do commit such fraud may, in fact, not have to pay for their ER visits at all, because of charity-care programs most hospitals have in place to provide deep discounts, even free care, to people on low incomes.

"If people are doing that to obtain service," he said, "then they likely don't know that if they're unable to pay, the hospital has resources set aside to accept charity applications, to write the bill off."

In other words, there's no reason to lie to the doctors.