WASHINGTON — President Trump on Thursday called for an end to “surprise medical bills,” the astonishingly high charges insured patients can face when a member of a medical team that treats them is not in their insurer’s network.

“Not a pleasant surprise,” Trump said of bills that arrive in the mail and run to tens of thousands of dollars. “A very unpleasant surprise.”

President Trump speaks during an event on medical billing in the Roosevelt Room of the White House on Thursday. Associated Press/Evan Vucci

The administration threw its support behind efforts by lawmakers of both parties to address the problem, laying out a set of goals for legislation.

With polls showing that voters trust Democrats over Republicans on health care, Trump has been hitting pocket-book medical issues that resonate with the middle-class, like prescription drug costs. He was joined at a White House event by patients, one who got a $110,000 bill after a heart attack, and another who got a bill for $17,850 for a test her insurer would have paid $100 for.

“So this must end,” Trump said. “We’re going to hold insurance companies and hospitals totally accountable.” The president said he wants to get it done “quickly,” and Sen. Lamar Alexander, R-Tenn., chairman of the Health, Education, Labor and Pensions Committee, said he hoped to deliver a bill in July.

Just before Trump spoke, the Democratic and Republican leaders of a key House committee said they are ready to move on legislation.

“No family should be left in financial ruin through no fault of their own, which is why we have been working together on a bipartisan solution to protect patients that we hope to announce soon,” Energy and Commerce Chairman Frank Pallone, D-N.J., and ranking Republican Greg Walden, R-Ore., said in a joint statement. The panel oversees the health insurance industry.

Pallone and Walden are not alone; more than a half-dozen senators and representatives have floated ideas or drafted legislation. Rep. Lloyd Doggett, D-Texas, chairman of the Ways and Means health panel, has a bill. Sens. Bill Cassidy, R-La., and Michael Bennet, D-Colo., collaborated on a bipartisan proposal, and other plans come from New Hampshire Democratic Sens. Maggie Hassan and Jeanne Shaheen.

“Surprise” bills amounting to tens of thousands of dollars can hit patients and their families when they are most vulnerable – after a medical emergency or following a complex surgical procedure. Often patients are able to negotiate lower charges by working with their insurers and the medical provider. But the process usually takes months, adding stress and anxiety. Sometimes it doesn’t work out and the bills are sent to collection agencies.

White House officials outlined a set of principles for legislation that Trump can back:

— Patients who receive emergency care should not be hit with charges that exceed the amount paid to in-network providers. In an emergency, patients are in no position to check whether their insurers have contracted with the surgeons or anesthesiologists who provide care.

— Patients going in for a scheduled procedure should get upfront information about whether their clinicians are in their insurer’s network and what costs they will face. Patients should not get out-of-network bills from a provider they did not pick.

— Fixes should not add to federal health care costs.

States also have been working to protect consumers from surprise medical bills. A survey of states by Georgetown University found that about half have acted to protect consumers. California, Connecticut, Florida and a handful of others, have the most comprehensive protections.

But states don’t have jurisdiction over most health plans sponsored by large employers, which cover about 100 million people and operate under the umbrella of a federal law.

A coalition that includes major insurers, business groups and consumer organizations has been pressing Congress for federal legislation. The basic elements would include informing patients when a doctor or service provider is out-of-network, setting a federal standard for what out-of-network clinicians can charge, and guaranteeing that the changes do not lead to premium increases.

A major hang-up has been agreeing on payment rates for out-of-network services that are mutually acceptable to medical specialists, hospitals and insurers, who have conflicting interests.

Another sticking point is the role of arbitration in settling billing issues. Some doctors’ groups favor arbitration, but White House officials who spoke with reporters Thursday said they’re not keen on it.

Trump’s move was applauded by America’s Health Insurance Plans, the main industry trade group. The Federation of American Hospitals, which represents for-profit institutions, expressed support for the goal of ending surprise billing, but cautioned against some proposed fixes.

Insurers form networks of doctors and hospitals, in part, to gain some leverage for negotiating reimbursements. Usually patients pay a bigger share of the bill for any care sought outside those networks.

But sometimes, patients don’t know they got care outside of their network until they get their bill.

Jack Hoadley, a research professor emeritus at Georgetown, told lawmakers last month that unexpected medical bills are a major concern for consumers, with two-thirds of Americans saying they are “very worried” or “somewhat worried” that they or someone in their family will receive a surprise bill.

He said programs like Medicare, Medicaid and veterans care protect consumers from out-of-network bills. But the same protections do not exist for most private insurance.