WASHINGTON - Hospitals routinely charge uninsured Americans up to four times as much for health care than patients whose insurance plans foot the bill, financial experts told lawmakers Thursday.

That overbilling, largely caused by hospitals seeking to cover growing indigent care costs, puts already financially strapped people at the mercy of aggressive debt collectors who threaten to deduct their wages, put liens on their homes and otherwise ruin their credit ratings.

"We're talking about people who don't have insurance because either they never had it, can't afford it, they've lost it," said Rep. Jim Greenwood, R-Pa., who chaired the hearing in front of a House oversight panel.

"An average working man or woman treated at a hospital can be stuck with a bill that is double what managed care or government programs pay," Greenwood said. "Then, to add insult to injury, they are sometimes aggressively pursued for these inflated debts. This situation is unfair and unjust."

Hospitals said the cash crunch would best be solved through universal health care coverage for Americans. An estimated 43 million Americans have no health insurance.

Hospitals in the Philadelphia area, for example, charged an average of $30,000 to treat a heart attack in 2002, said Dr. Gerard Anderson, director of the Center for Hospital Finance and Management at Johns Hopkins University. However, most insurance companies ultimately were asked to pay less than $10,000, he said.

Currently, hospitals charge uninsured patients two to four times as much for treatment as patients with health care coverage, he said.

Until recently, many hospitals refused to offer discount programs or otherwise let patients negotiate down their bills, fearing that doing so would violate federal fraud and abuse laws. But the U.S. Department of Health and Human Services clarified its guidelines earlier this year to "clearly enable hospitals and others to help patients who are experiencing financial hardship," said Lewis Morris, chief counsel to the agency's inspector general.

But the heads of several national hospital systems pleaded for help, saying they were trying to treat as many uninsured patients as possible while grappling with their own financial problems.

The Hospital Corporation of America, which operates nearly 200 hospitals in 23 states, lost $500 million last year for treating the uninsured, said chairman and CEO Jack O. Bovender Jr. Likewise, Tenet Health Care Corp., the nation's second-largest hospital chain, spends $15 million each month on patient care without hope of being paid, said president and CEO Trevor Fetter.

Earlier this month, class-action lawyer Richard Scruggs filed federal lawsuits in Jackson, Miss., against 13 not-for-profit hospitals in eight states alleging they inflated the amount of charity care they provide and that they used strong-arm tactics to collect money from the uninsured.