How much does a colonoscopy cost with Medicare in Peoria, AZ?

Nothing — if it stays a screening. A screening colonoscopy is one of the handful of things Medicare pays for at zero dollars: no deductible, no coinsurance, anesthesia included, provided your doctor accepts assignment. The bill only appears if the doctor finds something and takes it out, and even then the number is smaller than almost everything written about it says.

That last part is worth pausing on, because it is where nearly every article on this subject is now wrong. Search this question and you will be told you owe 20% if a polyp is removed. You do not. Congress put that coinsurance on a countdown years ago and it has already stepped down twice.

In 2026 it is 15%. On January 1 it becomes 10%. In 2030 it becomes nothing.

The number, and the date it changes

Here is the whole schedule, which comes from the Consolidated Appropriations Act of 2021 and is spelled out in CMS’s own instruction to Medicare contractors. It applies when a colonoscopy was planned as a screening and became diagnostic or therapeutic during the procedure — the claim goes in with a modifier that tells Medicare exactly that happened.

Source: CMS MLN Matters MM12656 and the CMS billing article on screening colonoscopy converted to diagnostic, confirmed against the Noridian Part B guidance that governs Arizona claims.

Two things follow from that table, and the second one is the useful one.

The first is that the Part B deductible does not apply. Because the encounter began as a colorectal cancer screening, the deductible is waived even after the procedure converts — so the $283 you would normally have to clear first is simply not in the arithmetic. You go straight to the percentage.

The second is that the year on the calendar decides the rate, not the year you booked. A procedure done on 22 December 2026 carries 15%. The same procedure on 8 January 2027 carries 10%. Nobody should postpone a cancer screening over a few percentage points, and if your doctor wants you seen now, be seen now. But if you are booking out into next year anyway — and in the north Valley, endoscopy schedules in the autumn routinely run into January — it is a small, real reason not to squeeze yourself into a December cancellation slot.

What Medicare covers, and how often

Colonoscopy is one of five colorectal screening routes Medicare pays for, each on its own clock. Noridian, the contractor that processes Arizona’s Part B claims, publishes the frequencies and the eligibility in one place.

Sources: Medicare.gov colonoscopy, stool DNA and fecal occult blood coverage pages, and Noridian Part B colorectal cancer screening guidance.

A few notes that do not fit in a table.

• There is no upper age limit. Medicare’s colonoscopy benefit does not stop at 75, or 80, or ever. Medicare also states there is no minimum age requirement for the screening. The 45-and-older figures above come from the eligibility criteria for the specific tests, and the guideline conversation about screening past 75 is a clinical judgment between you and your doctor — not a coverage cut-off.
• A positive stool test buys you a covered colonoscopy. This is a genuine improvement and not everyone has heard it. If a non-invasive stool-based test or a blood-based test comes back positive, the follow-up colonoscopy is billed as a screening rather than as a diagnostic procedure. It used to be the trap in the whole system: people took the at-home test because it was free, got a positive result, and then discovered the colonoscopy that had to follow it was not.
• The prep is a separate question. The bowel prep is a prescription or an over-the-counter product, and it runs through Part D or your own pocket rather than through Part B. It is rarely a large number, but it is not part of the zero-dollar screening.

Why the “free” colonoscopy came with a bill

Two different things cause this, and they are worth telling apart, because only one of them is a surprise.

The first is the polyp. Your screening was genuinely free, right up to the point where the doctor removed something. That conversion is the whole reason the reduced-coinsurance schedule exists, and the number you owe is now 15% of the Medicare-approved amount for the physician’s work. If it was done in a hospital outpatient department or an ambulatory surgical center — which is where most of these happen — the facility charges the same percentage as well. So there are two line items, not one, and people who were expecting one get a second envelope a week later and assume they have been billed twice.

The second is the word on the order. If your colonoscopy was scheduled because you had symptoms, or because you had polyps last time and this is surveillance for a known condition, it may be coded as a diagnostic colonoscopy from the outset. That is a different animal entirely: the Part B deductible applies, and then 20% coinsurance rather than 15%. Same procedure, same room, same doctor, and roughly double the bill — decided by the reason written on the order weeks earlier.

There is a third, smaller one worth knowing about: assignment. The zero-dollar screening price depends on the provider accepting Medicare assignment — agreeing to the Medicare-approved amount as payment in full. Nearly everyone in the Valley does. It costs nothing to confirm it when you call, and it is the same check that matters for everything else Medicare pays a percentage of.

What changes on a Medicare Advantage plan

The screening does not change. Medicare Advantage plans have to deliver your Part A and Part B benefits, so a screening colonoscopy is covered and is normally $0 in network — that is not a plan feature anybody is doing you a favour with.

What changes is the three things around it.

1. Cost sharing once it converts. Removing a polyp is no longer a zero-cost-sharing preventive service, so your plan’s own rules apply instead of the 15%. That usually means a flat outpatient-surgery or ambulatory-surgical-center copay, and it varies a great deal between plans on the same Maricopa County menu.
2. Network. The endoscopy center and the anesthesiologist both need to be in network, and they are not always the same answer as the gastroenterologist. This is the ordinary Medicare Advantage network question in a setting where people rarely think to ask it.
3. Prior authorization. Plans can require it. It is generally handled by the practice, but “generally” is doing work in that sentence, and a denied authorization discovered on the morning of the procedure is a bad morning.

All three are written in your plan’s Evidence of Coverage, and any change to them for next year is listed in the Annual Notice of Change your plan is required to have in your hands by September 30. Those letters are landing right now, which is why the ANOC letter is the one piece of post not to file unopened this month.

If you are on Original Medicare with a supplement, the 15% behaves like any other Part B coinsurance — the lettered plan picks it up according to its standardized benefits, and the practical answer for most Medigap holders is that the polyp costs them nothing at all.

The Peoria version of this

Peoria runs nearly thirty miles north to south, and where you live in it changes the logistics of this procedure more than it changes the coverage.

Plan availability is set by county, so the menu in 85383 is the menu in 85345 — that part I have written about at length. What differs at the north end is the driving. A great many Vistancia, Trilogy and Blackstone households already make the trip down Lake Pleasant Parkway to Arrowhead, or south into Sun City, for specialist care, and gastroenterology is exactly the kind of specialty where that pattern shows up. So the network question is not “does my plan cover colonoscopies” — every plan does. It is whether the specific endoscopy center your gastroenterologist uses sits inside your plan’s network, which is a narrower question and a more useful one.

Two local wrinkles I run into repeatedly:

• Recent arrivals on an out-of-state plan. North Peoria is full of people who moved here in the last few years and are still carrying a plan bought somewhere else. A screening colonoscopy is often the first time that plan gets tested against an Arizona provider, and it is a poor moment to find out the network stops at a state line. If that is you, moving to Arizona has its own set of rules and a window attached to them.
• Seasonal residents. If you are away four or five months a year, scheduling a colonoscopy around the calendar is annoying enough without the plan making it harder. This is one of the ordinary reasons a Medicare Supplement ends up fitting a Westbrook Village or Trilogy household better than a network plan does — it travels, and a provider in another state who accepts Medicare is simply a provider who accepts Medicare.

If your address sits on the Peoria–Glendale–Sun City seam, the Peoria and Glendale service-area pages are two halves of the same picture, and the seam is real enough that neighbours a mile apart can be quoted differently.

What to do between now and December 7

Open enrollment runs 15 October to 7 December, and this is one of the few coverage questions where a decision made in that window has a visible price attached to it in the spring. The full timeline for 2027 is here; the colonoscopy-specific version is short.

1. Read the outpatient surgery line in your Annual Notice of Change. Not the premium. The copay for outpatient surgery or an ambulatory surgical center is where a converted colonoscopy lands on an Advantage plan, and it moves more often than people expect.
2. Check the endoscopy center, not just the doctor. Ask the gastroenterology practice which facility they use, then check that facility against the plan directory. Two different records.
3. Ask whether your next one is a screening or a surveillance exam. If you have had polyps before, you may be on the 24-month high-risk clock — which is still a screening, still zero dollars, and worth knowing rather than guessing.
4. If it is already scheduled for the turn of the year, note the date. A procedure with a 2027 date of service carries the 10% rate rather than 15% if something is removed. Do not move a needed procedure to chase it; do not squeeze into December for no reason either.

The short version

• A screening colonoscopy costs nothing under Part B when the provider accepts assignment — no deductible, no coinsurance, anesthesia included.
• If a polyp is removed, it converts and you owe a reduced coinsurance: 15% in 2026, 10% in 2027 through 2029, and nothing from 2030. Most of what is published still says 20%, and that has been out of date for years.
• The Part B deductible is waived when the procedure started life as a screening.
• A colonoscopy ordered as diagnostic is different — the $283 deductible plus 20%. The reason written on the order decides it.
• Frequency is every 120 months, or every 24 months if you are high risk, and there is no upper age limit on the benefit.
• A positive stool or blood-based test earns a covered follow-up colonoscopy billed as a screening.
• On Medicare Advantage the screening is still $0, but the plan’s cost sharing, network and prior-authorization rules take over the moment it converts.

If you would rather have someone check it for you

None of this is a reason to choose a plan. It is a reason to know what you have before you need it, which is a different and much easier job — and it sits alongside the things that actually decide a plan: whether your doctors are in the network, what your prescriptions cost on the formulary, and what happens if you are out of state when something goes wrong. That review is a long afternoon on your own and about twenty minutes with someone who does it weekly, and there is no charge for it.

Bring your insurance cards and the actual pill bottles rather than a remembered list, and bring the Annual Notice of Change letter now that it has arrived. If you would like rough numbers on the year before we talk, the Medicare cost estimator will put them on paper, and what Medicare does not pay for is the wider map of where the coverage stops.

The office is in Anthem, roughly 25 minutes from north Peoria out the Carefree Highway and down Lake Pleasant Parkway, and most of this gets done by phone anyway. Call (602) 844-6002 or book a time — and if you call or text, that is your consent for me to reply the same way.

And whatever the arithmetic says: if you are due for the screening, go and have it. The cheapest colonoscopy is still the one that finds the thing early.