President Trump urged Congress to outlaw surprise medical bills in remarks delivered from the White House on Thursday.

He did not put forward a specific policy proposal for how to ensure federal law protects patients from the big, unexpected bills that Vox and other news outlets have covered extensively.

Instead, he urged Congress to come up with new legislation to ensure that patients no longer receive exorbitant bills from out-of-network doctors who practice at in-network facilities. There is already some bipartisan interest in tackling this problem, with the Senate leading the charge to find a solution.

“This must end,” Trump said in his remarks. “We’re going to hold insurance companies and hospitals accountable.”

As many as one in five emergency room visits lead to a surprise bill from an out-of-network provider involved in the care. This includes patients like Scott Kohan, a 35-year-old man taken to the emergency room by ambulance after a violent attack left him unconscious on the streets of downtown Austin.

The hospital the ambulance took Kohan to was in network, but the doctor who performed emergency jaw surgery on him wasn’t — and he ended up with a $7,924 bill as a result.

“In hindsight, I don’t know what I could have done differently,” Kohan told Vox last year. “I couldn’t go home. I had a broken jaw in two places. I tried to check if the hospital was in network.”

The White House is urging Congress to come up with a way to bar doctors from sending bills like the one Kohan received. There are multiple policy avenues to getting there, including setting caps on how much doctors can charge or requiring doctors to turn to the insurance company (and not the patient) when they feel they are owed additional reimbursement.

“We want Congress to step forward underneath our principles,” a senior administration official told reporters on a Thursday morning briefing call. “We’re hopeful that Congress will react to the president and will work on the details so we can deliver a bicameral solution that ensures patients are protected.”

“Surprise” medical bills are common in emergency rooms

In the past six months, Vox has collected more than 2,100 emergency room bills submitted by readers in all 50 states and Washington, DC, as part of an investigation into emergency room billing practices.

The dominant storyline to emerge is what anyone who has visited an emergency room might expect: Treatment is expensive. Fees have risen sharply in the past decade. And when health insurance plans don’t pay, patients are left with burdensome bills.

Vox’s database shows that patients are especially vulnerable to these surprise bills when out-of-network doctors work at in-network hospitals.

When doctors and hospitals join a given health insurance plan’s network, they agree to specific rates for their services, everything from a routine physical to a complex surgery.

Doctors typically end up out of network when they can’t come to that agreement — when they think the insurance plan is offering rates that are too low but the insurer argues that the doctor’s prices are simply too high.

Unless states have laws regulating out-of-network billing — and most don’t — patients often end up stuck in the middle of these contract disputes.

The Trump administration is focused on tackling two types of surprise medical bills. The first type is those from emergency rooms, when patients go to an in-network facility and end up with an out-of-network provider.

The second is surprise bills from scheduled surgeries, where the doctor performing the procedure is in network but another person involved in the care (often the radiologist or anesthesiologist) does not have a contract with the patient’s insurance.

The Trump administration has released a policy principle document that urges Congress to prohibit both those type of bills.

There are at least three ways Congress could outlaw surprise bills

Senators on both sides of the aisle have already been working on legislation to outlaw surprise medical bills for months. The biggest question for them is what type of policy intervention would work best.

At least three policy ideas have circulated around Capitol Hill and exist in some form as state-level legislation.

Idea 1: set a limit on how much out-of-network doctors can charge for their services. A legislative proposal this past fall from Sen. Bill Cassidy (R-LA) would ban out-of-network providers from billing patients directly, instead requiring them to seek additional funds from the insurance plan. The insurance plan would then be required to pay the higher of two amounts: the median in-network rate negotiated by health plans or 125 percent of the average amount paid to similar providers in the same geographic area.

Idea 2: force insurers and doctors into an arbitration process to settle a good price. A separate legislative proposal led by Sen. Maggie Hassan (D-NH) would also bar doctors from directly pursuing patients for funds beyond what the insurance plan paid. It would instead require the doctor to enter into an arbitration process with the insurer, where the two parties would work with a neutral arbiter to settle on a fair price.

New York has had a law like this in place for two years, and it has been used to settle about 2,000 billing disputes. Consumer advocates are happy with how the law has worked, as are the hospitals, and early economic research suggests that it’s working. Some early research suggests it may have reduced prices in New York too.

Idea 3: bundle doctor fees with the hospital charges. Patients never get surprise bills from the nurses involved in their medical care because the price of their care is worked into the overall hospital bill. Prominent health policy experts at places like the Brookings Institution and the American Enterprise Institute have suggested that doctor fees should work similarly: that they should be bundled into the hospital charges for providing care. This would be another avenue for ensuring that patients don’t receive additional bills from doctors, because their fees would be worked into the hospital bill.

Right now the ideas that seem to have the most traction in Washington are the latter two: creating an arbitration process or bundling doctor fees with hospital charges. But that could change and develop as Congress now works to respond to the president’s call for action.