A doctor’s willingness to “accept assignment” is one of the quietest cost switches in all of Medicare, and most enrollees never think to ask about it. When a provider does not accept assignment, federal rules let that provider bill up to 15% more than the Medicare-approved amount for a service, and the patient is on the hook for that extra slice. On a routine visit the difference is small, but on surgery, imaging, or a specialist consult it can turn into hundreds of dollars a beneficiary did not budget for.
What “accepting assignment” actually means
Accepting assignment means a provider agrees to take the Medicare-approved amount as full payment for a covered service. According to Medicare’s cost rules, most doctors and suppliers accept assignment, which caps what they can charge and keeps a beneficiary’s out-of-pocket exposure predictable.
A “non-participating” provider is different. Such a provider still treats Medicare patients but has not agreed to accept the approved amount as payment in full. That opens the door to what Medicare calls the limiting charge, the reason the same procedure can cost two retirees noticeably different amounts depending only on which office they walked into.
The mechanics reward asking a single question at the front desk before an appointment: does this provider accept Medicare assignment? A yes closes off the surcharge entirely.
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How the 15% excess charge is calculated
The surcharge is not simply 15% of what an in-network doctor would collect. A non-participating provider’s fee schedule is set at 95% of the standard participating amount, and the limiting charge is then 115% of that reduced figure. The net result is a ceiling of roughly 109% of the participating fee, with the beneficiary responsible for the gap on top of the usual Part B coinsurance.
Geography matters, too. Eight states, including New York, Pennsylvania, Massachusetts, and Ohio, prohibit Part B excess charges outright, so a retiree in those states cannot be billed the extra amount no matter how a provider files. Everywhere else, the charge is legal as long as the provider has not formally opted out of Medicare altogether.
The distinction between non-participating and fully opted-out is worth keeping straight. A provider who has opted out of Medicare bills the patient directly under a private contract, and Medicare pays nothing at all, an entirely separate and larger financial risk than the 15% limiting charge.
The Medigap plans that erase the charge
For retirees who want the surcharge gone regardless of which doctor they see, the fix runs through supplemental coverage. Two Medigap policies, Plan F and Plan G, cover Part B excess charges in full, meaning the beneficiary pays nothing extra even when a provider does not accept assignment. Medicare’s Medigap guidance lays out how these standardized plans map benefits, and excess-charge coverage is one of the lines that separates the pricier plans from the leaner ones.
That coverage is one reason the assignment question matters less for someone already holding Plan F or Plan G, and more for a beneficiary on Original Medicare alone or on a plan that leaves the gap exposed. Weighing a slightly higher Medigap premium against the odds of hitting excess charges is the kind of arithmetic that pays off over a retirement, especially for anyone who sees specialists regularly.
Beneficiaries with limited income have a further backstop. State Medicare Savings Programs can pick up Part B costs for those who qualify, and Medicare directs enrollees to check whether they are eligible for help with Part A and Part B expenses before assuming every bill is theirs to pay.
The practical takeaway is small but durable: confirm assignment before the appointment, know whether your state bans excess charges, and understand whether your supplemental coverage closes the gap. Each of those is a fixed piece of information that turns an unpredictable surcharge into something a retiree can see coming and plan around.
This article was researched and drafted with the assistance of artificial intelligence.
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