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Does Medicare cover a colonoscopy?

Yes. Medicare Part B covers a screening colonoscopy at no cost to you when the provider accepts assignment, once every ten years at average risk and once every two years at high risk. The catch most people hear about is real: if a polyp is found and removed, the test is no longer billed as a screening, and in 2026 you pay 15 percent.

This page is about the colonoscopy and the other colorectal cancer screenings. For how often Medicare pays for blood work and other lab tests, see our free chart of Medicare's screening schedules.

What the test is

Medicare.gov: "Colonoscopy screening tests check for precancerous polyps (growths in the colon), cancer, and other diseases inside the rectum and colon." And: "Part B covers screening colonoscopies. There's no minimum age requirement to get a screening."

How often Medicare pays

Medicare.gov: "Once every 24 months if you're at high risk for colorectal cancer. If you aren't at high risk, Part B covers the test once every 120 months, or 48 months after a previous flexible sigmoidoscopy."

The national coverage rule counts it in months. For the average-risk code it says "once every 10 years (i.e., at least 119 months have passed ...)," and for the high-risk code "once every 24 months for beneficiaries at high risk." Medicare's provider chart adds that for a high-risk patient who had a screening flexible sigmoidoscopy, the colonoscopy is covered "only after at least 47 months."

Who counts as high risk

Medicare's preventive services guide lists four things: "Your risk for colorectal cancer increases if: You've had colorectal cancer before. You have a history of polyps. You have a close relative who had colorectal polyps or colorectal cancer. You have inflammatory bowel disease (like ulcerative colitis or Crohn's Disease)."

There is no minimum age, and no upper age is written down

Medicare's preventive services guide: "If you're 45 or older, Medicare covers most colorectal cancer screenings, including screening colonoscopies, blood-based bio-marker screening tests, computed tomography (CT) colonography screenings, fecal occult blood test screenings, flexible sigmoidoscopy screenings, and multi-target stool DNA screening tests." Then, in a separate sentence: "There's no minimum age requirement to get a Medicare-covered screening colonoscopy."

The provider chart says who is covered for a screening colonoscopy: "Aged 45 and older at normal colorectal cancer risk (there's no minimum age requirement for screening colonoscopies) / At high colorectal cancer risk." That is "45 and older," with no upper number. Compare the stool DNA and blood tests, where the same chart writes the age as "Aged 45–85 years." Where Medicare means to stop a benefit at an age, it writes the age down. For the colonoscopy, it has not.

After 75

People ask this because of the U.S. Preventive Services Task Force, whose May 18, 2021 recommendation says: "The USPSTF recommends screening for colorectal cancer in adults aged 45 to 49 years," and "in all adults aged 50 to 75 years," and that doctors should "selectively offer screening ... in adults aged 76 to 85 years."

That is a recommendation about who should be screened. Medicare's payment rule, quoted above, has no upper age for a screening colonoscopy. A person over 75 who is within the frequency limit is inside Medicare's rule. Whether the test is a good idea at 76, or at 84, is between you and your doctor, and this page does not say.

What you pay

Medicare.gov: "If your doctor or other health care provider accepts assignment, you pay nothing for the screening test(s)." The provider chart: "No copayment, coinsurance, or deductible."

If a polyp is found and removed

Medicare.gov: "If your health care provider finds and removes a polyp or other tissue during the colonoscopy, you pay 15% of the Medicare-approved amount for your provider's services." The preventive services guide adds the facility: "In a hospital outpatient setting or ambulatory surgical center, you also pay the facility a 15% coinsurance. The Part B deductible doesn't apply."

Why 15 percent, and why does it matter which year it is? Before 2022, the rule was different. CMS's notice to providers, MM12656, explains: "Prior to January 1, 2022, when a screening colonoscopy became a diagnostic, the beneficiary was liable for the full applicable coinsurance." Congress then set a schedule that phases the coinsurance out. MM12656 lays it out: "For dates of service in CYs: 2023–2026, coinsurance is 15% / 2027–2029, coinsurance is 10% / Starting 2030, no coinsurance."

The Claims Processing Manual carries the same schedule as an instruction to Medicare's contractors: "for dates of service in CY 2023 through CY 2026, when the PT modifier is appended ... contractors shall continue to waive deductible and shall apply a reduced coinsurance of 15% ... For dates of service in CY 2027 through CY 2029 ... 10% ... For dates of service on or after January 1, 2030, contractors shall continue to waive deductible and shall waive coinsurance."

So in 2026 the answer is 15 percent, with no deductible. In 2027 it becomes 10 percent. From 2030 a polyp removal during a screening colonoscopy costs you nothing.

A colonoscopy after a positive stool or blood test

If a stool test or blood test comes back positive and your doctor sends you for a colonoscopy, Medicare treats that colonoscopy as a screening. Medicare.gov: "Part B also covers a follow-up colonoscopy as a screening test." The preventive services guide: "If you get a positive result after having a Medicare-covered, non-invasive stool-based colorectal cancer screening test (fecal occult blood test or multi-target stool DNA test) or a blood-based biomarker screening test, Medicare covers a follow-up colonoscopy as a screening test."

The provider chart says what that means for you and for the calendar: "The patient pays nothing for the screening test if their doctor or other qualified health care provider accepts assignment. The frequency limitations described for screening colonoscopies in Tables 1 and 2 don't apply in this scenario." The Claims Processing Manual says the same: "Deductible and coinsurance do not apply to the non-invasive stool-based tests nor the screening colonoscopy because both tests are specified preventive screening services." The provider marks the claim with a KX modifier to show the connection.

The other colorectal screening tests

A colonoscopy is one of several screenings Medicare covers. From the preventive services guide and the provider chart:

• Fecal occult blood test (a stool test). "Once every 12 months."
• Multi-target stool DNA test and blood-based biomarker test. "Once every 3 years if you meet all these conditions: You're between 45–85..." The provider chart adds that you must be "Asymptomatic" and "At average colorectal cancer risk."
• CT colonography. "Once every 60 months (or once every 24 months if you're at high risk), or 48 months after a previous flexible sigmoidoscopy or colonoscopy."
• Flexible sigmoidoscopy. "Once every 48 months for most people."

The Claims Processing Manual sets the starting age for these: "the minimum age for screening flexible sigmoidoscopy is reduced to 45 years and older," with the same sentence for the fecal occult blood test.

The codes on the claim

In one line: G0121 is a screening colonoscopy for someone not at high risk, G0105 is a screening colonoscopy for someone at high risk, modifier PT on the claim shows that a screening became a diagnostic or therapeutic procedure because a polyp or other tissue was removed, and modifier KX shows a colonoscopy that follows a positive stool or blood test.

If you have Medicare Advantage

Medicare's preventive services guide says: "If you have a Medicare Advantage Plan, another Medicare health plan, or both Medicare and Medicaid, your coverage, costs, and rules might be different. Check with your plan or state Medicaid office for more details about the preventive services they offer." For what can and cannot change under a plan, see Medicare Advantage and lab tests.

Before you go

This is ClaraCover's checklist, built from the rules above. Three questions for the office that books the procedure.

1. "Is this being booked as a screening?" Screening is $0 with assignment. Ask which code is on the order, and whether the provider accepts assignment.
2. "What would I owe if a polyp is found?" In 2026 the rule is 15 percent to the provider and, at a hospital or surgery center, 15 percent to the facility, with no deductible. Ask them to put a dollar figure on it.
3. "Is the facility a hospital outpatient department or an ambulatory surgery center?" Those are the two settings where the facility coinsurance applies if a polyp is removed.

Sources

• Medicare.gov: Colonoscopies
• Medicare.gov: Your Guide to Medicare Preventive Services (booklet 10110, May 2026)
• CMS: Medicare Preventive Services educational tool (MLN006559), Colorectal Cancer Screening Tests entry
• CMS: Medicare Claims Processing Manual, chapter 18, section 60, Colorectal Cancer Screening
• CMS: Transmittal R13921CP (August 27, 2026), revising chapter 18, section 60
• CMS: MLN Matters MM12656, Changes to Beneficiary Coinsurance for Additional Procedures Furnished During the Same Clinical Encounter as Certain Colorectal Cancer Screening Tests
• CMS: National Coverage Determination 210.3, Colorectal Cancer Screening Tests (version 8, effective June 8, 2026)
• U.S. Preventive Services Task Force: Colorectal Cancer, Screening (final recommendation dated May 18, 2021)

Checked September 27, 2026. This page explains published Medicare rules. It is not medical or insurance advice, does not say who should have a colonoscopy or at what age, and cannot tell you whether your own test will be covered or what your bill will be; your doctor's office and Medicare can. ClaraCover has no relationship with any provider or plan.