Patient advocates say more and more claims are being denied for medical services that consumers assume are covered by their insurance company.

After receiving a series of misdiagnoses, William Townsend was still feeling ill. Finally, during a family visit, he was taken to an emergency room in New Jersey in 2016.

“They discovered that there was a huge amount of fluid collecting around my heart,” Townsend, who owns a comic book store in Schenectady, New York, told Healthline. “If I had waited another few days, fluids would have squeezed it.”

To help him, doctors stuck a tube into Townsend’s chest to drain the fluids. He was released 11 days later.

Once he was cured, he faced another battle.

Townsend had a high-deductible health insurance plan, and he soon found himself socked with a medical bill totaling $180,000.

His insurer paid less than half of the bill and never explained why. Townsend scurried to cobble together the rest of the payment.

His story isn’t unique.

Experts say that insurers are increasingly denying valid claims that can range from essential services such as emergency room care and vital medical devices to treatments that some insurers refer to as “lack of medical necessity.”

In a story for the Los Angeles Times, writer David Lazarus shares how his medical claim for a new insulin pump was denied by his insurer. Although Lazarus has type 1 diabetes, the pump was labeled “lack of medical necessity.”

“This fight is a gray area,” Lisa Zamosky, senior director of consumer affairs at eHealth, told Healthline. “When insurers review these cases, something that seems medically necessary is determined not to be. That determination is an ongoing fight.”

For patients, claim denials of any kind can be devastating.

More than one-fourth of U.S. adults struggle to pay their medical bills, according to the Kaiser Family Foundation. And medical debt is already the most likely path to bankruptcy.

The American College of Emergency Physicians is sounding the alarm that emergency room claims are being denied.

Based on a secret list of diagnoses, Anthem Blue Cross Blue Shield is denying this coverage in six states, according to the physicians group.

If an emergency visit doesn’t end up being an emergency, patients have to foot the bill.

“If someone goes into an emergency room with symptoms, insurers should pay,” Dr. Darria Long Gillespie, a doctor and spokesperson for the American College of Emergency Physicians, told Healthline. “Doctors may not know the cause until they get imaging.”

Fear of racking up emergency room costs shouldn’t be a reason to delay care, Gillespie added.

For their part, doctors are already swamped with paperwork for insurers, she said, and they currently spend 30 to 50 percent of their time just plowing through it.

“This is a factor in physician burnout,” she said.

But other claims can get kicked out too, add experts. Denials can also include medical devices, mental health, physical therapy, medications — even walkers.

“It’s getting harder for patients to get services,” Dr. Linda Girgis, a family physician in New Jersey, told Healthline. “Often we have trouble understanding why.”

Even tests such as MRIs and ultrasounds need prior authorization, she noted.

After several unanswered calls to his insurer, Townsend ended up hiring a patient advocate to help him.

The advocate, Adria Gross, spent months writing letters and making phone calls to reduce Townsend’s claim. Finally, in 2017, the hospital ate most of the expenses.

Townsend says he paid only $6,200 out of his own pocket.

A lengthy claims appeals process is usually what awaits other patients, though.

Don’t be afraid to file an appeal and keep fighting, counsels Girgis.

“Every insurer has its own set of guidelines and what is covered,” she said. “And you don’t find out until you get the bill.”

But appeals can pay off handsomely. Experts estimate that at least half of all appeals are won by patients, although far fewer go that route.

Some claim denials are simple to fix. These include things such as wrong billing codes, which can be cleared up by calling the insurance company’s billing department.

For more complex appeals, find out why your claim was denied and how the process works, say experts.

“Along the way, get everything in writing,” said Gross.

One of her clients was given verbal approval over the phone that a claim would be paid.

“The insurer took it back, and it was never paid,” she said.

If an appeal to an insurer fails, there’s another option.

Patients have a legal right to an external review with a state’s insurance department.

“It will either uphold or not uphold the insurer’s decision,” said Zamosky.

Don’t ignore the medical bill, though, she cautions.

“High-deductible providers are getting more aggressive about going after funds,” Zamosky said. “So your case may end up in collections.”