Last June, Jay Comfort flew to the United States from his home in Switzerland to attend his only daughter's wedding. But the week before the ceremony — on a Friday evening — Comfort said he found himself in "excruciating pain."

"I tried to gut it out for three hours because of the insurance situation," said Comfort, a retired teacher and American citizen who has Swiss insurance.

When the pain became unbearable, Comfort called his brother, who drove him and his wife, Nazuna, a few miles to the nearest emergency department, at the University of Pittsburgh Medical Center's hospital in Williamsport, Pennsylvania.

Every bump of the drive was "like someone taking something and just jabbing it into my abdomen," he said.

At the hospital, Nazuna Konishi Comfort handed over her husband's Swiss insurance card, which confirmed coverage by Groupe Mutuel. Jay recalled the staff making copies of his insurance card and then treating his acute appendicitis. Doctors performed emergency surgery to remove the inflamed appendix.

Diagnostic tests confirmed he had a rare cancer, which doctors in Switzerland later removed with another surgery after he returned home. "It was a miracle," Comfort said, adding that the cancer was completely removed.

After his appendectomy, Comfort recalled vomiting and then waiting in a recovery room. In all, he spent about 14 hours at UPMC Williamsport before being released. He attended his daughter's wedding and, eventually, traveled back to Switzerland.

Then the bill came.

The patient: Leslie "Jay" Comfort, 66, a retired educator who worked in Japan and Switzerland. Comfort pays a monthly fee and deductible for Switzerland's mandatory basic health insurance, which he has with the Swiss-based Groupe Mutuel. His benefits — and the prices for procedures — are defined by the Swiss government.

Medical service: Emergency laparoscopic appendectomy and diagnostic tests, which showed Comfort had a rare subtype of cancer called goblet cell adenocarcinoma.

Service provider: University of Pittsburgh Medical Center Williamsport, which is about 3½ hours northeast of Pittsburgh. The UPMC health system is one of the state's largest employers, with 40 hospitals.

Total bill: $42,156.50, covering emergency surgery, scans, laboratory testing, and three hours in a recovery room. His insurer has said it will pay him about $8,184 (7,260.40 in Swiss francs), which is double the procedure's price in Switzerland. This left him to cover the remaining roughly $34,000.

What gives: Although Comfort has health coverage, his Swiss insurance had no contract with the U.S. hospital where he underwent emergency surgery — or with any other provider outside Switzerland.

With what is considered an excellent health system, Switzerland has the highest prices for medical care in Europe. As in the U.S., the country relies on private insurers and hospitals. But the cost of care in Switzerland is substantially lower than what is charged in the U.S., so the reimbursement his insurer offered is a fraction of what Comfort owes the U.S. hospital.

"I'm trying to do the right thing and say I'm willing to pay my responsibility," he said.

Groupe Mutuel does not have agreements with foreign providers, such as UPMC, and does not deal with them directly, said Lisa Flückiger, a spokesperson for Groupe Mutuel. The insurer originally agreed to reimburse Comfort what would have been paid in Switzerland for the same treatment in a public hospital and then double that because it was an emergency in a foreign country — a total of 4,838 in Swiss francs, or about $5,460.

While helpful, Comfort said, that amount wouldn't pay off the $42,156.50 he owes UPMC.

UPMC has expanded its reach throughout Pennsylvania and is now the largest provider of care in many parts of the state. In 2016, it purchased a smaller health system and now runs two majors hospitals, UPMC Williamsport and UPMC Williamsport Divine Providence Campus.

Studies show that in areas where hospital consolidation is high, prices go up. Because there is less competition, hospitals have more power to charge what they want when patients have private insurance or are paying out-of-pocket.

In the U.S. the amounts charged for medical care are "all over the map," said Johnathan Clarke, vice president of strategy and business development at Penfield Care, a medical cost-containment company in Canada. The company negotiates medical bills on behalf of individuals, including international visitors to the U.S., but is not involved in Comfort's case.

Clarke said he would expect an appendectomy to be priced between $6,500 to $18,800, based on his analysis of Medicare payments in the Pittsburgh area. Healthcare Bluebook — which evaluates insurers' claims data to provide cost estimates based on what insurers have paid, rather than what providers charge — says a fair price for a laparoscopic appendectomy in Williamsport is about $14,554.

Comfort said a "reasonable price estimate" based on his own internet research would be between $7,500 and $12,000.

Comfort's care included an X-ray and an EKG, or electrocardiogram for his heart, because "there was no information relating to past medical/surgical history for this patient," wrote Susan Manko, vice president of public relations at UPMC. The staff also conducted pathology work that identified cancer.

But those additional services did not fully explain the gap between cost estimates and what the hospital charged. For instance, UPMC charged $8,357 for Comfort's three-hour stay in the recovery room.

Manko said Comfort's total bill aligns with UPMC's standard charges.

The cost disparities highlight the stark difference in international pricing. Cost estimates last year showed the average amount paid for an appendectomy in the U.S. was "nearly exactly double" that paid in Switzerland, said Christopher Watney, chief executive of the International Federation of Health Plans, an industry association whose members include health insurers on six continents.

Health care in Switzerland, though, is often expensive compared with other European countries, Watney said. The Swiss pay double for an appendectomy compared with Germans, and more than three times that of those in Spain, he said. Across the globe, Watney said, many countries include an overnight stay in the cost of an uncomplicated appendectomy in contrast to Comfort's experience, which was billed as outpatient care.

Comfort, who has dual residency in Switzerland and Japan after nearly three decades working abroad, said he worked in the U.S. long enough to qualify for Social Security benefits and Medicare. He said he had previously tried to gain Medicare coverage at one point but still is not enrolled, after being transferred to a couple of offices and "playing phone tag."

Still, unlike many patients dealing with a five-figure medical bill, Comfort said he is not concerned about UPMC harming his financial reputation. The health system doesn't "seem to put bad marks against people's credit record — and I don't have credit in the United States. I've been out for 30 years."

Manko confirmed that, saying UPMC reviewed and updated its collection policy last year; it states the health system will not engage in "extraordinary collection actions" such as lawsuits, liens on homes, arrests, or reporting to credit agencies.

She said the health system — which, as a nonprofit system, is tax-exempt — maintains a "robust financial assistance program" for patients unable to pay. But "to our knowledge" Comfort has not applied for financial assistance, Manko told KFF Health News.

The resolution: Comfort said he spent months waiting for a bill and finally reached out to UPMC because, if the bill had arrived this year, he would have had to pay his insurance deductible again on top of the charges.

Comfort received a full UPMC bill six months after his surgery. Manko said there was "confusion" at the time of Comfort's ER registration. Comfort's wife provided the insurance information, she said, "but there was no documentation in the patients record for address, policy number or policy holder information."

Once Comfort received his bill, he realized it was much higher than his Swiss insurance reimbursement and, frustrated, contacted KFF Health News.

Flückiger said the original payment amount Comfort's insurer calculated was specifically for the appendectomy and did not include the scan or laboratory costs. After receiving questions from a KFF Health News reporter, Groupe Mutuel "realized that we have not included the laboratory analysis and the CT scan," which are not routinely part of an appendectomy, Flückiger wrote.

After KFF Health News provided a detailed summary of the UPMC bill, the insurer increased the amount it would pay Comfort. In all, the insurer said, Comfort should receive 7,260.40 in Swiss francs, or about $8,184.

Comfort still hopes to negotiate directly with UPMC to reduce what he owes.

"I don't want to try to walk away, saying I don't owe you anything," Comfort said. "That's not right. We're moral people, you know. But if you're going to try to gouge me and play the power trip and think you're going to try to get everything you can out of me, I won't play that game."

The takeaway: Though the Affordable Care Act was meant to provide insurance to more Americans and bring down the cost of care, hospital bills remain extraordinarily high and highly variable.

For a nonemergency, Comfort could have tried to compare prices at other hospitals. But most hospitals in the area where he fell ill are owned by UPMC. And an inflamed appendix can't wait for comparison shopping.

Clarke, the cost-containment expert, said the "only thing" Comfort could have done differently was to purchase a travel health insurance policy before leaving Switzerland. While prices for health care in continental Europe are comparable to Switzerland, the high cost of care in the U.S. means Groupe Mutuel insurance is "insufficient."

That is especially important for visitors to the U.S. since, as Robin Ingle, CEO of travel insurance company Ingle International, said: U.S. prices are "kind of crazy numbers."

KFF Health News, formerly known as Kaiser Health News (KHN), is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF — the independent source for health policy research, polling, and journalism.

Emmarie Huetteman of KFF Health News edited the digital story, and Taunya English of KFF Health News edited the audio story. NPR's Will Stone edited the audio and digital story.