A screening colonoscopy is covered at no cost to you under Medicare Part B, with no deductible and no coinsurance, as long as no polyps or tissue are found and removed during the procedure. If something is found and removed, you’ll pay 15% of the Medicare-approved amount. For a diagnostic colonoscopy (one ordered because of symptoms or a prior condition), standard Part B cost-sharing applies: you pay 20% of the Medicare-approved amount after meeting your annual deductible.
The total you actually spend depends on whether anything is found, where the procedure takes place, and whether you have supplemental coverage. Here’s how to estimate your real out-of-pocket cost.
Screening vs. Diagnostic: Why It Matters
Medicare draws a sharp line between screening and diagnostic colonoscopies, and that distinction controls what you pay. A screening colonoscopy is a routine check for colorectal cancer in someone with no current symptoms. Medicare covers it once every 10 years for people at average risk, or once every 2 years for those at high risk (a category that includes people with a personal or family history of colorectal cancer, polyps, or inflammatory bowel disease).
A diagnostic colonoscopy is ordered when you already have symptoms like rectal bleeding, unexplained weight loss, or a change in bowel habits, or when a prior test flagged something that needs a closer look. Diagnostic procedures fall under standard Part B rules: you pay 20% coinsurance after your annual Part B deductible, which is $257 in 2025.
The tricky part is that a procedure can start as a screening and get reclassified. If your doctor finds and removes a polyp during what was supposed to be a routine screening, the procedure is no longer fully free. You’ll owe 15% of the Medicare-approved amount for your doctor’s services, plus 15% of the facility fee if you’re at a hospital outpatient department or ambulatory surgical center. The Part B deductible still doesn’t apply in this situation, which helps, but the 15% coinsurance catches many people off guard.
How Much You’ll Pay by Facility Type
Where you have your colonoscopy performed has a significant impact on cost. Medicare’s 2026 national average prices for a colonoscopy with polyp removal illustrate the gap clearly:
- Ambulatory surgical center: The total Medicare-approved amount averages $833, with a facility fee of $656. The average patient payment is $166.
- Hospital outpatient department: The total Medicare-approved amount averages $1,399, with a facility fee of $1,222. The average patient payment is $279.
That’s a difference of roughly $113 in out-of-pocket costs just based on the setting. Ambulatory surgical centers, which are independent facilities designed for same-day procedures, consistently cost less than hospital-based locations because their facility fees are lower. If you have a choice, asking your doctor whether an ambulatory surgical center is an option could save you money.
These figures are national averages. Prices vary by region, and your actual cost may be higher or lower depending on where you live and which providers are involved. You can look up procedure-specific estimates for your area on Medicare’s Procedure Price Lookup tool at Medicare.gov.
The Polyp Removal Surprise
This is the single most common source of unexpected colonoscopy bills for Medicare beneficiaries. You schedule a routine screening expecting to pay nothing. During the procedure, your doctor spots a polyp and removes it, which is standard medical practice and exactly what the screening is designed to catch. But that removal changes your cost-sharing from 0% to 15%.
Polyps are found in roughly 25% to 40% of screening colonoscopies in people over 50, so this isn’t a rare scenario. Based on the national averages above, if a polyp is removed at an ambulatory surgical center, you’d owe about $125 to $170. At a hospital outpatient department, expect closer to $200 to $280. These amounts cover both the doctor’s services and the facility fee.
Congress has been gradually reducing this coinsurance. It dropped from 20% to 15% starting in 2023 and is scheduled to decrease by 5 percentage points every few years until screening colonoscopies with polyp removal are fully free. But for now, 15% is the current rate.
Additional Costs to Expect
The procedure itself isn’t the only line item on your bill. Most colonoscopies involve sedation, typically administered by an anesthesiologist or nurse anesthetist. Medicare Part B covers anesthesia services, but the cost-sharing rules depend on whether the colonoscopy is classified as screening or diagnostic. For a clean screening with no findings, anesthesia is covered at 100%. If polyps are removed or the procedure is diagnostic, you’ll owe your applicable coinsurance on the anesthesia charges as well.
Pathology is another common add-on. When tissue is removed, it’s sent to a lab for analysis. This generates a separate bill from the pathologist, also subject to Part B cost-sharing. The amounts are usually modest (often $20 to $50 for your share), but they add to the total.
If your doctor doesn’t accept Medicare assignment, you could face excess charges up to 15% above the Medicare-approved amount. Providers who accept assignment agree to charge only the Medicare-approved rate, so confirming this before your procedure eliminates that variable.
How Supplemental Coverage Reduces Your Cost
If you have a Medigap (Medicare Supplement) policy, it will typically cover some or all of your remaining coinsurance. Most Medigap plans, including the popular Plan G and Plan N, cover Part B coinsurance at 100%, which means the 15% or 20% you’d otherwise owe for polyp removal or a diagnostic colonoscopy would be picked up by your supplement. With a Medigap plan, your out-of-pocket cost for a colonoscopy is often zero or close to it.
If you’re on a Medicare Advantage plan instead of Original Medicare, your costs depend on your specific plan’s benefits. Medicare Advantage plans must cover everything Original Medicare covers, but they set their own copayment and coinsurance amounts. Some plans charge a flat copay for outpatient procedures, which could be higher or lower than the 15% to 20% you’d pay under Original Medicare. Check your plan’s Evidence of Coverage document or call the number on your member card to get an exact estimate before scheduling.
Keeping Your Costs as Low as Possible
A few practical steps can minimize what you spend. First, choose an ambulatory surgical center over a hospital outpatient department when your doctor gives you that option. The savings are meaningful and the quality of care for routine colonoscopies is comparable. Second, confirm that every provider involved in your procedure, including the anesthesiologist and any consulting pathologist, accepts Medicare assignment. A single non-participating provider can add unexpected charges to an otherwise predictable bill.
Third, understand the timing rules. If you have your screening colonoscopy even one day before the eligible interval has passed (10 years for average risk, 2 years for high risk), Medicare may not cover it as a screening, and you’d be responsible for diagnostic-level cost-sharing. Your doctor’s office can verify your eligibility window. Finally, if you have both Medicare and a Medigap policy, make sure your providers have your supplement information on file so claims process correctly the first time.