Colonoscopy Billed as Diagnostic Instead of Preventive

You scheduled a routine screening colonoscopy, confirmed with your insurer that it was covered at 100% under preventive care, and then a bill arrived weeks later for hundreds — sometimes thousands — of dollars. Nothing went wrong medically. The doctor simply found and removed a polyp, which is exactly what a colonoscopy is supposed to catch. Yet suddenly you owe money. This is one of the most common and most frustrating billing surprises in American healthcare, and it happens to millions of people every year. This article explains exactly why it happened, what your rights are depending on your plan type, and what steps you can take right now to dispute or reduce the charge.

Why Your Colonoscopy Was Reclassified From Preventive to Diagnostic

When your doctor removes or biopsies a polyp during a colonoscopy, the procedure changes in the eyes of your insurance company — even though nothing changed in your experience of the procedure. A preventive colonoscopy is billed under a specific set of CPT codes (CPT stands for Current Procedural Terminology — the standardized codes that describe every medical service). The most common preventive screening code is CPT 45378. The moment a polyp is removed, an additional code gets added — such as CPT 45385 for a snare polypectomy — and many insurers automatically reclassify the entire claim as diagnostic rather than preventive.

A diagnostic procedure is one performed to investigate a symptom or finding, rather than to screen a healthy person. Under most insurance plans, diagnostic services are subject to your deductible, copay, and coinsurance — the cost-sharing that does not apply to preventive services. Your insurer is not necessarily doing anything illegal by making this change. For years, this reclassification was an accepted practice permitted under federal rules.

The ACA Rule and the Loophole

The Affordable Care Act (ACA) requires most health plans to cover recommended preventive services — including colonoscopies for adults aged 45 and older — at no cost to the patient. No deductible. No copay. No coinsurance. This requirement applies to non-grandfathered plans, meaning plans that were created or substantially changed after March 23, 2010. If your plan started before that date and has not changed significantly since, it may be exempt — but the vast majority of plans sold today are non-grandfathered.

The loophole was this: the ACA said screening colonoscopies must be free, but it did not originally say anything about what happens when a polyp is found during that screening. Insurers treated the polypectomy as a separate diagnostic service, applied your deductible and coinsurance to it, and charged you accordingly. Legally, they had room to do this — and most did.

The 2023 Rule Change: Did It Fix This?

A federal rule that took effect for plan years beginning on or after May 31, 2022 — meaning most plans saw it apply starting January 1, 2023 — specifically addressed this problem. The rule states that if a polyp is removed or a biopsy is taken during what began as a preventive screening colonoscopy, the insurer cannot impose cost-sharing on that removal or biopsy. The preventive screening nature of the visit is supposed to be preserved even when the doctor treats something discovered during the procedure.

This sounds like a complete fix. In practice, it is not — for several reasons:

• Plan year matters. The rule applies to your plan's year, not the calendar year. If your employer's plan year runs July to June, the rule may have applied to you starting July 2023, not January 2023. Check your Summary of Benefits and Coverage document for your plan year start date.
• Insurer compliance is uneven. Some insurers have been slow to update their claims systems. Others apply the rule correctly to in-network providers but not to out-of-network situations.
• Grandfathered plans are exempt. If your plan is grandfathered, this rule does not apply to you.
• Self-insured employer plans have more flexibility. Many large employers self-insure, meaning they pay claims directly and use an insurance company only to administer the plan. These plans are governed by federal ERISA law and are not required to follow state insurance rules, though they are still required to follow federal ACA preventive care mandates for non-grandfathered plans.

According to the Centers for Medicare and Medicaid Services (CMS), the 2022 rule change was intended to close this specific gap, but patients should verify compliance with their own plan rather than assuming it is being applied correctly.

A Concrete Example of What This Can Cost You

Imagine you have a PPO plan with a $1,500 annual deductible and 20% coinsurance after the deductible. You have not met your deductible yet this year. You go in for a routine screening colonoscopy. The gastroenterologist removes one small polyp. The total billed amount for the procedure is $3,200. Your insurer accepts $2,400 as the contracted rate.

Under the old (pre-2023) approach, the insurer reclassifies the claim as diagnostic. You owe $1,500 toward your deductible, then 20% of the remaining $900 — that is $180 — for a total out-of-pocket cost of $1,680. Your "free" preventive screening just cost you $1,680.

Under the 2023 rule, if your plan year started on or after May 31, 2022, the insurer should not apply your deductible to the polypectomy portion because the procedure originated as a preventive screening. Your cost should be $0. If you received a bill like the first scenario and your plan year falls under the new rule, you have grounds to appeal.

What to Do Before Your Colonoscopy

The single most effective step you can take is to ask questions before the procedure, not after you receive a bill.

1. Call your insurer and ask specifically: "If a polyp is removed during my screening colonoscopy, will cost-sharing apply?" Get the representative's name, the date and time of the call, and a confirmation or reference number. Write it down.
2. Ask your gastroenterologist's billing department: "What CPT codes will you submit if the procedure remains a screening? What codes will you submit if a polyp is found and removed?" Request this in writing — even an email confirmation is useful.
3. Confirm your plan year start date so you know whether the 2023 rule applies to you.
4. Ask whether your plan is grandfathered. Your insurer is required to disclose this in your Summary of Benefits and Coverage document.

The American Cancer Society emphasizes that cost concerns should not deter people from getting screened — but knowing the billing rules in advance puts you in a much stronger position if a dispute arises.

What to Do If You Already Received an Unexpected Bill

Do not pay the bill immediately. You have options, and paying can sometimes waive your right to dispute.

Step 1: Get the Itemized Bill and Explanation of Benefits

Request an itemized bill from the provider listing every CPT code and charge. Then pull your Explanation of Benefits (EOB) — the document your insurer sends after processing a claim that shows what was billed, what was allowed, and what you owe. Check these against each other. Billing errors are common and worth catching before you do anything else. Our guide on how to check medical bills for errors walks through this process step by step.

Step 2: File a Formal Appeal With Your Insurer

Every insurer is required to have an appeals process. Your EOB will include instructions on how to file. In your appeal letter, state clearly that:

• The procedure was scheduled and performed as a preventive screening colonoscopy.
• Under ACA Section 2713 and the May 2022 final rule (for applicable plan years), cost-sharing cannot be imposed when a polyp is removed during a preventive screening.
• You are requesting that the claim be reprocessed as preventive with no cost-sharing applied.

Attach your EOB, the itemized bill, and any written confirmation you received before the procedure. Our detailed guide on how to appeal a denied insurance claim covers the full process including timelines and what to do if the internal appeal is denied.

Step 3: Request an External Review

If your internal appeal is denied, you have the right to an independent external review — a federally guaranteed right for most non-grandfathered plans. An independent organization reviews the insurer's decision at no cost to you. Your denial letter must include information about how to request this review.

Step 4: File a Complaint With Your State Insurance Commissioner

If your insurer is unresponsive or the external review does not resolve the issue, file a complaint with your state's insurance commissioner. Every state has one. The National Association of Insurance Commissioners (NAIC) maintains a directory at naic.org where you can find your state's regulator. State regulators have authority to investigate insurer compliance with ACA preventive care rules for fully insured plans. If your employer self-insures, you can also file a complaint with the U.S. Department of Labor's Employee Benefits Security Administration (EBSA) at dol.gov/agencies/ebsa.

Step 5: Do Not Ignore a Surprise Bill While Appealing

Even if you are appealing, make sure the provider knows. Ask the provider to hold the bill while your appeal is pending to avoid it going to collections. You have rights here — our guide on what to do when you get a surprise medical bill covers how to communicate with providers during a dispute without damaging your credit.

What If the 2023 Rule Does Not Apply to Your Plan?

If your plan is grandfathered, or if you were seen before your plan's applicable year, you may not have a federal mandate to cite. You still have options. Ask the provider for a financial hardship reduction or a payment plan. Ask whether the polypectomy charge can be reduced or waived given that the procedure began as a preventive visit. Many providers have financial assistance programs. Negotiating a lower amount is far better than paying the full billed charge without question.

What to Do Next

If you have already received a bill, start with your itemized bill and EOB today. Identify the CPT codes, confirm your plan year, and determine whether the 2023 rule applies to you. If it does, file your internal appeal citing the ACA and the May 2022 rule by name. If you have not yet scheduled your colonoscopy, make two phone calls first — one to your insurer and one to the provider's billing department — and get the billing policy in writing before you walk through the door. Colorectal cancer is one of the most preventable cancers when caught early. A billing dispute should never be the reason you skip a screening, but you deserve to know exactly what you may owe before you go in.

Sources: CMS — Preventive Services Coverage Under the ACA, American Cancer Society — Colorectal Cancer Detection and Screening Recommendations