Medicare Preventive Services: What Part B Covers With No Deductible or Coinsurance

Most of Medicare's preventive services cost you nothing under Part B: no deductible, no coinsurance. The condition is in Medicare.gov's own sentence: "You pay nothing for most preventive services if you get the services from a health care provider who accepts assignment." Two words in that sentence do a lot of work. "Most" and "accepts assignment."

The rest of the fine print sits in frequency limits, eligibility rules, and the moment a screening turns into a diagnostic test because the doctor found something. That's where Florida seniors who expected no bill end up looking at a Medicare Summary Notice with the $283 Part B deductible on it. This post lists what Part B covers as preventive, how often, who qualifies, and the specific situations that turn a no-cost visit into a charge.

Source: Medicare.gov, Preventive & screening services; CMS, 2026 Part B premiums and deductibles; Medicare.gov, Colonoscopies; 42 CFR 410.152(l). CMS announces each year's Part B amounts in the fall; 2027 amounts weren't out as of Nov. 7, 2026.

What "no cost" actually means

Normally Part B works like this: you pay the yearly deductible, then 20% of the Medicare-approved amount for most services. For the services on the preventive list, federal rules flip that. Under 42 CFR 410.152(l), Part B pays 100% of the Medicare payment amount for screening mammograms, Pap tests and pelvic exams, flu, pneumococcal, hepatitis B and COVID-19 shots, cardiovascular and diabetes screening blood tests, bone mass measurement, the Welcome to Medicare visit, the annual wellness visit and more.

The catch is assignment. Medicare.gov defines it plainly: a provider who accepts assignment takes the Medicare-approved amount as payment in full and can charge you only the Medicare deductible and coinsurance. For a preventive service, that's zero.

A provider who doesn't accept assignment can charge more than the approved amount, in many cases up to 15% above it (the "limiting charge"), and may ask you to pay the whole bill at the visit. A provider who has opted out of Medicare is worse: Medicare won't pay at all, except in emergencies. So the first question for any screening is not "is this covered?" It's "do you accept Medicare assignment?"

The preventive services list

Here are the services most people on Medicare will run into, with Medicare.gov's eligibility and frequency rules. "Nothing" means no Part B deductible and no coinsurance for the service itself, with a provider who accepts assignment. Look at the last two rows before you assume everything on this list works that way.

Source: Medicare.gov coverage pages for each service, starting from Preventive & screening services (e.g. lung cancer, mammograms, cardiovascular, diabetes, prostate, glaucoma), accessed Nov. 7, 2026.

The full Medicare.gov list is longer: HIV and hepatitis B infection screening, PrEP for HIV, sexually transmitted infection screening and counseling, diabetes self-management training, medical nutrition therapy, the Medicare Diabetes Prevention Program, and a yearly cardiovascular behavioral therapy visit with your primary care provider. Each has its own eligibility rule, and some require a referral or a primary care setting.

A few details that trip people up. The lung cancer screening needs an order, and before the first scan you need a visit to talk through the benefits and risks. Medicare.gov describes 20 "pack-years" as an average of one pack a day for 20 years. Diabetes screening isn't automatic for everyone: you need one risk factor like high blood pressure or obesity, or two from a list that includes being 65 or older and being overweight. And depression screening itself has no cost sharing, but follow-up treatment with a mental health provider can involve a copayment or coinsurance.

Colorectal screening: the rules that changed

Colorectal screening has the most moving parts, and the rules have been rewritten in the past few years in your favor. Medicare covers several tests, and you and your doctor pick one.

Source: Medicare.gov: fecal occult blood tests, multi-target stool DNA tests, blood-based biomarker tests, CT colonography, flexible sigmoidoscopy, colonoscopies; 42 CFR 410.37.

A positive stool or blood test doesn't start a new bill. Under 42 CFR 410.37(k), when a Medicare-covered stool-based test or blood-based biomarker test comes back positive, the follow-on colonoscopy counts as part of the screening, and it isn't held to the usual frequency limits. Medicare.gov says you pay nothing for that follow-up colonoscopy with a provider who accepts assignment.

A polyp removed during a screening colonoscopy still costs something, but the share is shrinking. Under 42 CFR 410.37(j), a planned screening colonoscopy where the doctor removes tissue stays a screening test. The deductible doesn't apply. But Part B pays less than 100%, and the gap is your coinsurance. 42 CFR 410.152(l) sets the schedule: Medicare pays 85% through 2026, 90% for 2027 through 2029, and 100% starting January 1, 2030. In a hospital outpatient department or ambulatory surgical center, Medicare.gov says you owe that coinsurance on the facility charge as well as the doctor's.

0.0%10.0%20.0%30.0%

20.0%

15.0%

15.0%

15.0%

15.0%

10.0%

10.0%

10.0%

0.0%

20222024202620282030

Source: 42 CFR 410.152(l)(5)(i) (Medicare pays 80% in 2022, 85% in 2023–2026, 90% in 2027–2029, 100% from 2030); Medicare.gov, Colonoscopies (15% in 2026)

Show the numbers

	Coinsurance
2022	20.0%
2023	15.0%
2024	15.0%
2025	15.0%
2026	15.0%
2027	10.0%
2028	10.0%
2029	10.0%
2030	0.0%

Example (hypothetical): Say the Medicare-approved amount for the doctor's part of your screening colonoscopy with polyp removal is $400. In 2026 you'd owe 15%, or $60, with no deductible. The same procedure in 2027 would be 10%, or $40. If it's done in a hospital outpatient department or surgery center, there's a separate facility charge with the same percentage. Real amounts depend on the procedure and setting, so ask the office for the approved amounts in advance.

If you have a Medigap policy, that coinsurance is the kind of cost sharing it may pick up, depending on the plan letter. More on that below.

What turns a no-cost visit into a bill

None of these is a billing error. Each is Medicare working as written. Knowing them ahead of time is the whole game.

Source: Medicare.gov, Preventive & screening services; Mammograms; Yearly wellness visits; Does your provider accept Medicare as full payment?; CMS, Medicare Wellness Visits; Colonoscopies.

Screening vs. diagnostic. The mammogram page on Medicare.gov is the clearest example. A screening mammogram once every 12 months costs nothing with an assigning provider. A diagnostic mammogram, one that investigates a lump, a symptom or an abnormal earlier result, falls under regular Part B rules: after the deductible, you pay 20%. Same machine, often same building. The difference is why it was ordered.

Example (hypothetical): Say a diagnostic mammogram has a Medicare-approved amount of $150 and it's your first Part B service of 2026. The whole $150 goes toward your $283 deductible, so you pay $150. Had it been coded as a screening mammogram with an assigning provider, you'd pay nothing.

The same-day problem visit. CMS tells providers that when they do an annual wellness visit plus a "significant, separately identifiable, medically necessary" problem visit, Medicare may pay for both. You'd owe normal cost sharing on the second one. Mentioning your knee isn't wrong. Just know it can turn into a separate charge.

Frequency limits. Medicare.gov warns that "your doctor may recommend services that Medicare doesn't cover or offers too frequently." A cholesterol panel ordered as cardiovascular screening is covered every 5 years. Bloodwork for a condition you already have is a different service, billed under normal rules. When in doubt, ask why a test is recommended and whether Medicare covers it as preventive this time.

Welcome to Medicare and yearly wellness visits

Two visits sit at the center of the preventive benefit. The Welcome to Medicare preventive visit is a one-time visit within your first 12 months of Part B. After that, the yearly wellness visit comes around once every 12 months to build and update a prevention plan, including the screening checklist that maps onto the table above. Both cost nothing with an assigning provider, and neither is a physical: CMS says a routine physical isn't covered and patients pay 100% of it.

I won't repeat the details here. Our post on the Medicare annual wellness visit covers what happens in the room, the 12-month clock, and the billing traps around it. If you're turning 65 and want to use the Welcome visit window, your Part B start date is what starts it; our initial enrollment period guide explains how that date is set.

Medicare Advantage and Medigap

Medicare Advantage. Federal rules say Medicare Advantage organizations "may not charge deductibles, copayments, or coinsurance for in-network Medicare-covered preventive services" (42 CFR 422.100(k)). The services are the ones federal rules define as preventive in 42 CFR 410.152(l). The word that matters is "in-network." Out of network, or if a screening turns diagnostic, your plan's normal cost sharing applies, and it's spelled out in your own plan's Evidence of Coverage. Read that document rather than assuming.

Medigap. A Medicare Supplement policy doesn't change anything about services that already have no cost sharing. Where it matters is everything on the "what turns a visit into a bill" list: the 20% on a diagnostic test, the colonoscopy coinsurance, the glaucoma screening. Depending on the plan letter, Medigap pays some or all of that Part B cost sharing. In Florida, when you can buy a Medigap policy without health questions depends on specific windows; our post on Florida Medigap rules walks through them, and our Florida Medicare Supplement page explains how the plan letters differ.

What changes on Jan. 1, 2027

One thing changes for certain, and it's already in the regulation: coinsurance on a polyp or tissue removal during a planned screening colonoscopy or sigmoidoscopy drops from 15% to 10% on January 1, 2027, under 42 CFR 410.152(l). If you're on the fence about scheduling a screening colonoscopy for late December or early January, that's a real if modest difference, though medical timing should drive the decision, not a five-point coinsurance change.

The CY 2027 Physician Fee Schedule final rule, summarized in a CMS fact sheet dated Nov. 4, 2026, doesn't announce changes to which preventive services Part B covers or what beneficiaries pay for them. The items it does finalize are mainly provider payment and coding policies.

The 2027 Part B deductible is the open number. CMS announces next year's Part B premium and deductible each fall, and as of November 7, 2026, it hadn't published 2027 figures. The 2026 deductible is $283. That number matters here only when part of a visit stops being preventive.

What to do before your next appointment

1. Ask about assignment when you book. "Do you accept Medicare assignment?" is the single question that decides whether "nothing" means nothing.
2. Check your dates. Medicare.gov says you can log in to your secure Medicare account to check your preventive services. Look before booking anything with a frequency limit.
3. Ask how it's being ordered. Screening or diagnostic? If you have symptoms or a past abnormal result, expect diagnostic rules.
4. Keep the wellness visit about prevention. Bring up new problems knowing they may be billed separately, or book a second appointment.
5. For colonoscopy, ask about the facility. Hospital outpatient departments and surgery centers bill a facility charge, and polyp removal brings coinsurance on both parts.
6. Read your Medicare Summary Notice. If a screening shows up with a deductible or 20% and you think it was screening, call the provider's billing office first. If the claim itself was denied, our post on the Medicare appeal process explains the steps.

For one-on-one help, SHINE (Serving Health Insurance Needs of Elders), run by the Florida Department of Elder Affairs with the local Area Agencies on Aging, offers unbiased, confidential Medicare counseling at no cost, and preventive benefits are on the list of topics its volunteers handle. Call 1-800-96-ELDER (1-800-963-5337), TTY 1-800-955-8770, or use the contact form. Our SHINE guide explains how sessions work. For how Medicare fits together in Florida generally, see our Florida Medicare page.

FAQ

Do Medicare preventive services cost anything?

Most have no Part B deductible and no coinsurance if your provider accepts assignment. A few preventive services, like glaucoma screening and the digital rectal exam part of prostate screening, carry the deductible and 20% coinsurance.

Why did I get a bill for a screening?

Common reasons: the test was ordered as diagnostic because of a symptom or earlier finding, it was repeated sooner than Medicare's frequency limit, a separate problem was treated at the same visit, the provider doesn't accept assignment, or a polyp was removed during a screening colonoscopy.

Does Medicare cover a colonoscopy after a positive at-home stool test?

Yes. When a Medicare-covered stool-based or blood-based biomarker screening test is positive, the follow-on colonoscopy counts as screening, and you pay nothing for it if the provider accepts assignment.

What do I pay if a polyp is removed during a screening colonoscopy?

In 2026 you pay 15% of the Medicare-approved amount for the doctor and, in a hospital outpatient department or surgery center, 15% of the facility charge, with no deductible. Under federal rules that drops to 10% for 2027 through 2029 and to nothing starting in 2030.

Do Medicare Advantage plans cover preventive services?

Federal rules bar Medicare Advantage organizations from charging deductibles, copayments or coinsurance for in-network Medicare-covered preventive services. Out-of-network rules and diagnostic follow-ups depend on your plan's Evidence of Coverage.

Federal Medicare rules and your own plan or policy documents control what's covered and what you pay. Confirm your situation with Medicare, SHINE or a licensed agent before your appointment.

Sources

1. Medicare.gov: Preventive & screening services
2. Medicare.gov: Colonoscopies (screening)
3. Medicare.gov: Fecal occult blood tests
4. Medicare.gov: Multi-target stool DNA tests
5. Medicare.gov: Blood-based biomarker tests for colorectal cancer
6. Medicare.gov: CT colonography
7. Medicare.gov: Flexible sigmoidoscopy
8. Medicare.gov: Mammograms
9. Medicare.gov: Lung cancer screenings
10. Medicare.gov: Cardiovascular disease screenings
11. Medicare.gov: Cardiovascular behavioral therapy
12. Medicare.gov: Diabetes screenings
13. Medicare.gov: Bone mass measurements
14. Medicare.gov: Depression screening
15. Medicare.gov: Flu vaccines
16. Medicare.gov: COVID-19 vaccine
17. Medicare.gov: Pneumococcal vaccines
18. Medicare.gov: Hepatitis B vaccines
19. Medicare.gov: Hepatitis C screenings
20. Medicare.gov: Abdominal aortic aneurysm screenings
21. Medicare.gov: Alcohol misuse screenings & counseling
22. Medicare.gov: Counseling to prevent tobacco use
23. Medicare.gov: Obesity behavioral therapy
24. Medicare.gov: Cervical & vaginal cancer screenings
25. Medicare.gov: Prostate cancer screenings
26. Medicare.gov: Glaucoma screenings
27. Medicare.gov: Welcome to Medicare preventive visit
28. Medicare.gov: Yearly Wellness visits
29. Medicare.gov: Doctor & other health care provider services
30. Medicare.gov: Does your provider accept Medicare as full payment?
31. eCFR: 42 CFR 410.37, Colorectal cancer screening tests
32. eCFR: 42 CFR 410.152, Amounts of payment
33. eCFR: 42 CFR 422.100, General requirements (Medicare Advantage)
34. CMS: Medicare Wellness Visits
35. CMS: Annual Wellness Visit (provider guidance)
36. CMS: 2026 Medicare Parts A and B premiums and deductibles
37. CMS: CY 2027 Medicare Physician Fee Schedule final rule fact sheet (Nov. 4, 2026)
38. Florida Department of Elder Affairs: SHINE
39. SHINE: Contact us