Medicare covers outpatient surgery, but what you pay depends on which part of Medicare you have and where the surgery happens

Yes, Medicare covers outpatient surgery — surgery where you go home the same day without an overnight hospital stay. However, your costs and coverage details differ based on whether you have Original Medicare (Part A and Part B) or a Medicare Advantage plan, and whether the surgery takes place in a hospital outpatient department or an ambulatory surgery center.

Understanding these differences matters because your out-of-pocket costs can vary significantly. A procedure at a hospital outpatient department may cost you more than the same procedure at an ambulatory surgery center, even though Medicare covers both.

Key Takeaways

  • Original Medicare Part B covers outpatient surgery at both hospital outpatient departments and ambulatory surgery centers, but you pay a copay or coinsurance after you meet your deductible.
  • Medicare Advantage plans cover outpatient surgery, but your costs depend on your specific plan — some charge a copay per visit, others charge coinsurance, and some may require prior authorization.
  • Hospital outpatient departments typically charge you more than ambulatory surgery centers for the same procedure because of how Medicare reimburses each setting.
  • You should ask your surgeon's office whether the procedure is covered and what your out-of-pocket cost will be before the surgery date.
  • Anesthesia, imaging, and lab work related to your outpatient surgery are usually covered under the same rules as the surgery itself.

How Original Medicare Part A and Part B cover outpatient surgery

Under Original Medicare, Part B covers the surgeon's fee and the facility cost for outpatient surgery. You pay 20 percent coinsurance of the Medicare-approved amount for the surgeon and facility combined, after you meet your Part B deductible (which is $240 in 2024, though this amount changes yearly).

The facility where your surgery happens affects what you pay. At a hospital outpatient department, the hospital charges a facility fee in addition to the surgeon's fee. At an ambulatory surgery center, the facility fee is typically lower. Medicare reimburses each setting differently, so your coinsurance amount will differ even for the same procedure.

Related services — such as pre-surgery lab work, imaging, or anesthesia — are covered separately under Part B. You pay 20 percent coinsurance for each service after your deductible, unless the service is preventive (like a pre-surgery screening that qualifies as preventive care).

What Medicare Advantage plans cover for outpatient surgery

Medicare Advantage plans (Part C) must cover at least the same services as Original Medicare, including outpatient surgery. However, your out-of-pocket costs depend entirely on your plan's design. Some plans charge a copay per visit (for example, $150 for an outpatient surgery), while others charge coinsurance (a percentage of the cost). Some plans charge nothing for outpatient surgery at in-network facilities.

Many Medicare Advantage plans require prior authorization before you have outpatient surgery. This means your surgeon's office must contact your plan ahead of time to confirm the procedure is covered and to get approval. If your surgeon does not get prior authorization and your plan denies the claim, you may be responsible for the full cost.

Your plan's network matters too. If you have surgery at an out-of-network facility, you may pay more or the plan may not cover it at all. Always check your plan documents or call your plan before scheduling surgery to learn your exact costs and whether the facility is in-network.

Hospital outpatient departments versus ambulatory surgery centers

Both settings are covered by Medicare for outpatient surgery, but they operate differently and cost you different amounts. A hospital outpatient department is part of a hospital; an ambulatory surgery center is a standalone facility that performs surgery but does not admit patients overnight.

Medicare reimburses hospitals at a higher rate than ambulatory surgery centers for the same procedure. This means the facility fee at a hospital is usually higher, so your 20 percent coinsurance (under Original Medicare) will be higher too. For example, a cataract surgery might cost you $300 in coinsurance at an ambulatory surgery center but $450 at a hospital outpatient department.

Both settings must meet Medicare safety and quality standards. The choice between them often depends on where your surgeon has privileges and what your insurance plan covers. If you have a choice, ask your surgeon's office what the facility fee will be at each location so you can compare your out-of-pocket costs.

What to ask your surgeon's office before outpatient surgery

Before you schedule outpatient surgery, contact your surgeon's office and ask these specific questions: Is this procedure covered by Medicare? What is the Medicare-approved amount for the surgeon's fee and the facility fee? Will I need prior authorization, and if so, will your office handle it? What is my out-of-pocket cost?

If you have Original Medicare, your surgeon's office can tell you the Medicare-approved amount and you can calculate your coinsurance (20 percent after your deductible). If you have a Medicare Advantage plan, call your plan directly with the procedure code (your surgeon's office can provide this) and ask what your copay or coinsurance will be.

Ask whether related services like anesthesia, lab work, or imaging are included in the surgery cost or billed separately. Some facilities bundle these costs; others bill them separately, which means you may owe coinsurance for each service.

Costs you may owe for outpatient surgery under Original Medicare

Under Original Medicare, your costs depend on whether you have met your Part B deductible for the year. If you have not met it, you pay the full deductible first, then 20 percent coinsurance of the Medicare-approved amount for the surgery and related services.

If you have already met your deductible, you pay only 20 percent coinsurance. The total coinsurance depends on the Medicare-approved amount, which varies by procedure and location. For a minor procedure, your coinsurance might be $100 to $300. For a more complex procedure, it could be $500 or more.

If you have a Medigap policy (supplemental insurance), it may cover some or all of your coinsurance, depending on which Medigap plan you have. Check your Medigap policy or contact your Medigap insurer to learn what it covers for outpatient surgery.

Prior authorization and other requirements

If you have a Medicare Advantage plan, your plan may require prior authorization before outpatient surgery. This is your surgeon's office's responsibility to request, but you should confirm it has been done. If authorization is not obtained and your plan later denies the claim, you could be billed for the full cost.

Some Medicare Advantage plans also require you to use in-network providers. If you have surgery at an out-of-network facility without prior authorization, your plan may not cover it. Always verify that your surgeon and the facility are in-network before the surgery date.

Original Medicare does not require prior authorization for outpatient surgery, but it does require that the surgeon and facility accept Medicare assignment (meaning they accept the Medicare-approved amount as payment in full, minus your coinsurance). Most surgeons and facilities do accept assignment, but it is worth confirming.

Frequently Asked Questions

Does Medicare cover outpatient surgery at an ambulatory surgery center?

Yes, Medicare covers outpatient surgery at ambulatory surgery centers. Under Original Medicare, you pay 20 percent coinsurance after your deductible. Under Medicare Advantage, your cost depends on your plan. Ambulatory surgery centers typically have lower facility fees than hospital outpatient departments, so your out-of-pocket cost may be lower for the same procedure.

What if I have not met my Part B deductible yet?

If you have not met your $240 Part B deductible (in 2024), you pay the full deductible first. After that, you pay 20 percent coinsurance of the Medicare-approved amount for the surgery and related services. Once you meet your deductible in a calendar year, you only pay coinsurance for the rest of that year.

Will Medicare cover my anesthesia during outpatient surgery?

Yes, anesthesia is covered under Part B as part of your outpatient surgery. You pay 20 percent coinsurance for the anesthesiologist's fee after your deductible, just as you do for the surgeon's fee. The anesthesia cost is usually billed separately from the surgery itself.

Do I need prior authorization if I have Original Medicare?

No, Original Medicare does not require prior authorization for outpatient surgery. However, you should confirm that your surgeon and facility accept Medicare assignment before the surgery date. If they do not, you may owe more than the standard coinsurance.

What happens if my Medicare Advantage plan denies the outpatient surgery?

If your plan denies a claim for outpatient surgery, you have the right to appeal. Contact your plan and ask for the reason for the denial. Common reasons include lack of prior authorization, use of an out-of-network provider, or a information that the procedure is not medically necessary. Your surgeon's office can often help you appeal by providing medical documentation.