A knee replacement under the same Blue Cross Blue Shield plan cost about $16,000 at one North Carolina hospital this year and around $40,000 at another, a little more than an hour's drive away.
Those figures come from Serif Health, a San Francisco startup that collects data hospitals and insurers are now required to publish, and were reported in an analysis by KFF Health News. The lower price was at Catawba Valley Medical Center in Hickory. The higher was at Mission Hospital in Asheville, formed by the merger of the region's two largest hospitals.
This comparison is possible because of a rule most people have never heard of. Since 2021, the Centers for Medicare and Medicaid Services has required hospitals to disclose their prices in machine-readable files. For years, the data was too messy to use. It has now reached a point where a specific procedure at a specific hospital under a specific plan can be pulled out and compared.
Why This Procedure Is the One to Watch
Knee replacement is a useful test case for a reason that has nothing to do with orthopedics. It is common, it is standardized, and it is usually planned in advance, which is the narrow set of conditions under which comparing prices is even theoretically possible. Research cited in the KFF Health News analysis puts the procedure at more than a million times a year in the United States.
The pattern is not confined to North Carolina. In Melbourne, Florida, Holmes Regional Medical Center, part of a system that dominates surrounding Brevard County, charged Cigna twice what a hospital two hours north did for the same surgery this year. Banner North Colorado Medical Center in Greeley charged a UnitedHealthcare patient $20,000 more than a health system an hour south in Denver.
The gap is not limited to one operation, either. For a breast biopsy, UnitedHealthcare pays $7,500 at Mission and $1,700 at Catawba, according to the same data. For a hernia repair, it pays $17,700 at Mission and $9,600 at Catawba.
What Economists Say the Data Shows
The link between market power and price is the finding health economists have been pointing to.
"When hospitals have bargaining leverage, they tend to have higher prices," said Zack Cooper, an associate professor of public health and economics at Yale University who has spent more than a decade studying hospital monopolies. Over the last quarter century, Cooper said, hospital prices have risen faster than those in any other economic sector, and hospital consolidation is one of the primary drivers.
From 2002 to 2020, more than 1,000 hospital mergers took place nationally. Last year alone, hospitals and health systems announced 46 mergers and acquisitions, five of them valued above $1 billion, according to consulting firm Kaufman Hall.
Hospitals dispute that price comparisons tell the story. The American Hospital Association has argued that mergers can improve quality and reduce costs by creating a fiscally sustainable environment. A Mission Hospital spokesperson said it can be misleading to compare one hospital with another, noting that Mission is almost three times as large as Catawba Valley, operates as a Level 1 trauma center and serves a different population, and that pulling individual rates paints an incomplete picture.
Other measures point the same direction. A Rand Corporation team led by Christopher Whaley, now a Brown University health economist, uses commercial insurance records to compare hospital prices to Medicare rates. Those figures put Mission Hospital at 334% of Medicare in 2024 and Catawba Valley at 237%, against a state benchmark of 280%.
The Cost Reaches People Who Never Have Surgery
This is the part that determines whether the story matters to a household that is not scheduling an operation.
When insurers pay higher hospital prices, they raise premiums. The full cost for an employer to cover an average family health plan rose above $27,000 in 2025, up from $21,000 six years earlier, according to KFF figures. Nearly two-thirds of U.S. adults said they worried about affording health care in an April KFF poll.
In markets with a single dominant system, employees cannot opt out. Katie Button, chef and co-founder of an Asheville restaurant with about 100 employees, filed a class-action lawsuit in 2021 with five local residents alleging the monopoly has harmed them. The case is pending. "We are where we are because we don't have a choice of hospitals," Button said.
Patients paying a large share feel it directly. Marcelle Crago, an Asheville nurse and lactation consultant, was quoted more than $9,000 for meniscus surgery under a high-deductible plan. She postponed it, shopped around, and had it done at an unaffiliated outpatient center for less than a third of that. In responding to her complaint with the state, an attorney for the hospital and its owner, HCA Healthcare, wrote that charges represent the cost of supporting the entire episode of care and must cover investments in technology, training and staffing.
Using the Files Without Overestimating Them
For a planned procedure, comparison is now realistic in a way it was not a few years ago. Ask the hospital and the surgeon's office for a written good faith estimate before scheduling, and ask what it covers. Facility charges, surgeon fees, and anesthesia are often billed separately, so one number rarely captures the total.
Ambulatory surgical centers frequently price the same procedure well below hospital outpatient departments. For people paying cash or carrying a high deductible, the discounted cash price is worth requesting, since it is a distinct figure hospitals must publish.
The limits are real. Emergency care cannot be shopped, and plans restrict which facilities are in network. In consolidated markets there may be only one. Analyses have repeatedly found the published files inconsistent and difficult to interpret, and the Government Accountability Office has recommended that CMS assess whether the files are complete and accurate enough to be usable.
Enforcement of updated federal price transparency requirements began April 1, and CMS has an open comment docket with submissions due August 31. At least 519 hospitals have received a warning notice or corrective action plan request over transparency deficiencies since April, according to reporting on federal enforcement, though only 28 hospitals have been penalized to date.
Key Questions Answered
What do the price files actually contain? Hospitals must publish gross charges, discounted cash prices and payer-specific negotiated rates for the items and services they provide, in machine-readable format.
How large is the price difference for a knee replacement? In the reported data, about $16,000 at one North Carolina hospital and around $40,000 at another under the same insurance plan.
Why do prices differ so much? Health economists point to bargaining leverage in consolidated markets. Hospitals point to differences in size, trauma designation, patient population and cost structure.
Does this affect people who are not having surgery? Yes, indirectly. Higher hospital prices feed into premiums for everyone in the plan.
Can patients actually use this data? For planned procedures, yes. Emergency care and narrow networks limit how far comparison shopping goes.
What should someone ask before scheduling? A written good faith estimate, what it includes, whether facility and physician fees are separate, and the discounted cash price if paying out of pocket.
Is anything changing at the federal level? Enforcement of updated requirements began April 1, and CMS has an open comment docket with submissions due August 31.
