In 2015, Facebook founder Mark Zuckerberg and his wife, Priscilla Chan, donated $ 75 million to the San Francisco General Hospital for the construction of a Level I trauma center, the only facility of its kind in San Francisco. The hospital was later renamed Zuckerberg San Francisco General.

The largest public hospital in the city, Zuckerberg San Francisco General deals with 20% of Franciscans of San, according to the website of the hospital. But patients who end up in the hospital may be surprised after an ambulance trip and treatment, because the Zuckerberg San Francisco General does not take out private insurance.

After a year-long investigation in which he examined several case studies of patients in debt after routine treatments, Vox discovered that the Zuckergerg San Francisco General was outstanding in billing. After being run over by a bicycle car, Nina Dang was taken to Zuckerberg San Francisco General and treated for a broken arm. Doctors also did a scan of his brain and spine. His bill: $ 24,074, his insurance covering only $ 3,830.

Five other bills reviewed by Vox revealed a similar trend: private insured patients sent huge bills for treatment, without any recourse to their insurance cover to protect them.

The Zuckerberg San Francisco General, unlike most hospitals, does not negotiate prices with health insurance providers. It is considered "off-grid" for all private insurance plans. The hospital focuses instead on patients with public health plans, such as Medicare and Medicaid, recovering patients with private insurance what the hospital loses by caring for the uninsured and underinsured . In the case of Dang, the Zuckerberg San Francisco General charged 12 times the rate of his Medicare for his treatment.

"It's a pretty common thing," said a spokesman for the hospital at Vox. "We are the trauma center of the entire city. Our mission is to serve underserved people because of their financial needs. We must be listening to this population. "

Contrary to the hospital's position, only 1% of national ambulances carry patients to off-grid emergency rooms, according to a study by economist Christopher Garmon of the University of Missouri in Kansas City. The study also revealed that about 20% of emergency admissions across the country resulted in a surprise medical bill. Because of its size and its first-class emergency room, the Zuckerberg San Francisco General hosts a third of the city's ambulances, which means that a large number of its patients, some of whom are oblivious to their arrival, are not aware of the unusual lack of support from the hospital for their insurance.

"According to what I saw, it's unusual," Garmon told Vox. "I've heard anecdotes about hospitals trying a strategy like this, but I have the impression that it does not last very long."

Robert Berman, from the Systemedic Medical Billing Service, nodded. "So that the emergency service is off the grid? It's a bit strange, "Berman told Vox.

Newsweek contacted General Zuckerberg San Francisco for comments and will update this story when he responds.

Emergency room patients were trying to reduce off-grid bills in a 2009 class action suit against Zuckerberg San Francisco General, but the decision was not favorable, as the hospital's billing system is legal in California.

Only 21 states, including California, have enacted legislation to protect patients from unexpected billing when hospitals and insurance companies do not agree on off-grid payments.