Medicare covers a screening colonoscopy once every 10 years for people at average risk of colorectal cancer, or once every 2 years for those at high risk. Coverage begins at age 45, and in most cases, you pay nothing for the screening itself. The specifics of what you’ll owe depend on whether polyps are found and where the procedure takes place.
Coverage for Average-Risk Beneficiaries
If you have no personal or family history of colorectal cancer, inflammatory bowel disease, or polyps, Medicare considers you average risk. In that case, Part B covers one screening colonoscopy every 120 months (10 years). There’s no coinsurance and no Part B deductible for the screening portion of the procedure, as long as your doctor accepts Medicare assignment.
The 10-year interval resets from the date of your last screening colonoscopy. If you had one at age 65, your next covered screening would be at 75. Your doctor may recommend a shorter interval based on your individual health, but Medicare won’t cover an earlier screening unless you meet the high-risk criteria.
Coverage for High-Risk Beneficiaries
Medicare shortens the interval to once every 24 months (2 years) if you’re considered high risk. You qualify for this more frequent schedule if you have:
- A personal history of colorectal cancer or adenomatous polyps
- A close family history of colorectal cancer or adenomatous polyps (parent, sibling, or child)
- Inflammatory bowel disease, including Crohn’s disease or ulcerative colitis
The same zero-cost rules apply to high-risk screening colonoscopies. You pay no coinsurance and no deductible, provided no polyps are removed during the procedure.
What You Pay If Polyps Are Removed
This is where costs can surprise people. A colonoscopy that starts as a routine screening but turns into a therapeutic procedure (because the doctor finds and removes a polyp or tissue) triggers a cost-sharing change. You’ll owe 15% of the Medicare-approved amount for your provider’s services. If the procedure happens in a hospital outpatient setting or ambulatory surgical center, you also pay the facility a 15% coinsurance on top of that.
The good news: the Part B deductible does not apply, even when polyps are removed during a screening. This protection has been in place since 2023 and can save you several hundred dollars compared to what a standard diagnostic procedure would cost. Still, the 15% coinsurance on polyp removal can add up depending on the complexity of the procedure and your facility’s charges. A Medigap or Medicare Advantage plan may cover some or all of that remaining cost.
Screening vs. Diagnostic Colonoscopies
The coverage rules above apply only to screening colonoscopies, meaning procedures ordered to check for cancer in someone with no current symptoms. If your doctor orders a colonoscopy because you’re experiencing symptoms like rectal bleeding, unexplained weight loss, or a change in bowel habits, that’s classified as a diagnostic colonoscopy. Diagnostic procedures fall under standard Part B rules: you pay 20% coinsurance after meeting your annual Part B deductible.
The classification matters more than most people realize. A diagnostic colonoscopy can cost you several hundred dollars out of pocket, while a screening colonoscopy for the same procedure is free (unless polyps are found). Make sure you and your doctor’s office are clear about how the procedure will be coded before it’s scheduled.
Other Screening Tests Medicare Covers
Colonoscopy isn’t the only colorectal screening option Medicare pays for. If you prefer a less invasive test between colonoscopies, or if a colonoscopy isn’t appropriate for you, several alternatives are covered on different schedules.
Fecal occult blood test (FOBT) or FIT test: Covered once every 12 months for beneficiaries 45 and older. At least 11 months must pass after the month of your last covered test. This is a simple stool sample you can do at home.
Cologuard (multi-target stool DNA test): Covered once every 3 years for beneficiaries aged 45 to 85 who are asymptomatic and at average risk. This is also a home-based stool test but checks for both blood and DNA markers associated with cancer.
Blood-based biomarker test: Covered once every 3 years for beneficiaries 45 and older. This is a newer option that screens for colorectal cancer through a standard blood draw.
All of these alternatives are covered with no cost to you. However, if any of these tests come back positive, you’ll need a follow-up colonoscopy. That follow-up is covered as a screening colonoscopy, though cost-sharing rules for polyp removal still apply if tissue is found and removed.
How Age Affects Your Coverage
Before 2023, most Medicare screening tests required you to be at least 50. That minimum dropped to 45 for stool-based tests, blood-based biomarker tests, and colonoscopies, aligning Medicare with updated recommendations from the U.S. Preventive Services Task Force. If you’re on Medicare before 65 due to a disability or end-stage renal disease, you now qualify for screening as early as 45.
There’s no upper age limit written into Medicare’s colonoscopy coverage. However, the Cologuard test is only covered through age 85. For beneficiaries over 85, colonoscopy, FOBT, and FIT testing remain the covered screening options. Your doctor can help you weigh the benefits of continued screening based on your overall health and life expectancy.
Timing Your Next Screening
Scheduling matters because Medicare counts months, not calendar years. For a colonoscopy, 119 full months must pass after the month of your last procedure before your next one is covered. If you go too early, even by a few weeks, you could be responsible for the full cost. Your doctor’s billing office can check your Medicare claims history to confirm when your next screening is eligible for coverage. You can also log in to your Medicare.gov account and review your claims to see the exact date of your last covered screening.