How to Dispute a Medical Bill: The Itemized Bill, the No Surprises Act, the Insurer Appeal and the $25 Federal Dispute
A large share of medical bills contain errors, and a federal law now caps what you owe for care you could not choose. Neither helps unless you ask.
The short version
- Request an itemized bill with codes before paying anything, and compare it to the insurer's explanation of benefits; errors are common and providers correct them when asked.
- For emergency care, out-of-network providers at in-network facilities and air ambulances, the No Surprises Act limits you to in-network cost sharing; the provider cannot bill the balance.
- Insurer denials can be appealed internally within 180 days and then to a binding external review; uninsured patients billed $400 over a good faith estimate can file a $25 federal dispute within 120 days.
Medical bills arrive weeks after the care, in codes most patients cannot read, from providers the patient may never have met, and with a due date that assumes the number is right. Often it is not. Hospital billing audits routinely find errors in a majority of itemized bills; insurers deny claims they later pay on appeal; and until 2022, patients who went to an in-network hospital could be billed thousands by an out-of-network doctor they did not choose. The law now gives patients more leverage than most use. This guide sets out the steps, in order, from the first envelope to the dispute that ends it.
Step 1: Get the itemized bill and the explanation of benefits
A summary bill shows a total. An itemized bill shows every charge with a billing code — CPT codes for procedures, HCPCS codes for supplies and drugs, revenue codes for hospital departments — and is the only version you can check. Ask the provider's billing office for it in writing; you are entitled to it, and hospitals subject to the federal price transparency rule must also post their standard charges. Then get the explanation of benefits from your insurer, which shows what was billed, what the plan allowed, what it paid and what it says you owe. The two documents should match. Where they do not, you have found the dispute.
Step 2: Look for the common errors
| Error | What it looks like | What to do |
|---|---|---|
| Duplicate charges | The same code billed twice; a medication charged per dose and per day | Ask for removal of the duplicate |
| Services not received | A test that was ordered and cancelled; a consultation that did not happen | Ask for the medical record entry supporting the charge |
| Upcoding | A longer or more complex visit code than the encounter warranted; an emergency room level higher than the care provided | Ask for the documentation that justifies the level billed |
| Unbundling | Components of a single procedure billed separately at higher total cost | Cite the bundled code; insurers' software usually catches this, patients' bills often do not |
| Wrong insurance or patient details | Claim sent to an old plan, or denied for a mismatched name or date of birth | Have the provider resubmit; the clock on insurer appeals runs from the denial, not the service |
| Balance billing where it is barred | A bill from an out-of-network doctor at an in-network hospital, or for emergency care, exceeding your in-network cost share | See Step 3 |
Put every dispute in writing to the billing office, one error per paragraph, with the code and the reason, and ask for a corrected bill. Ask the provider to put the account on hold while it reviews; most will.
Step 3: Check the No Surprises Act
Since January 2022, federal law has barred balance billing in three situations:
- Emergency care, at any hospital or freestanding emergency department, including the care needed to stabilize you and post-stabilization care until you can safely be transferred — regardless of network status.
- Out-of-network providers at in-network facilities: the anesthesiologist, radiologist, pathologist, assistant surgeon or hospitalist you did not choose, at a hospital or ambulatory surgical center in your plan's network.
- Air ambulance transport, though not ground ambulances, which remain the largest gap in the law and are regulated by some states.
In those situations you owe only what you would have owed in-network — your deductible, copay or coinsurance, counted toward your in-network limits — and the provider and insurer must settle the rest between themselves through the law's arbitration process, which does not involve you. A provider may ask you to sign a notice-and-consent waiver for certain scheduled, non-emergency out-of-network services; you may refuse, and the waiver is not valid for emergency care or for ancillary providers such as anesthesiologists. If you receive a balance bill in a protected situation, tell the provider in writing that the bill violates the No Surprises Act, send a copy to your insurer, and report it to the federal No Surprises Help Desk at 1-800-985-3059 or your state insurance department. The law covers employer plans and individual market insurance; Medicare and Medicaid have their own balance billing protections.
Step 4: Appeal the insurer
- Read the denial. The explanation of benefits must state the reason — not medically necessary, out of network, prior authorization missing, coding error — and your appeal rights.
- Internal appeal. File in writing within 180 days of the denial, with a letter from your doctor explaining why the care was necessary, the relevant records, and any plan language that supports coverage. The insurer must decide within 30 days for care not yet received and 60 days for care already received; 72 hours in urgent cases.
- External review. If the internal appeal fails, request an independent external review within four months. The reviewer's decision is binding on the insurer. State insurance departments run or oversee the process for state-regulated plans; the federal government does for self-funded employer plans.
- Ask for help. State consumer assistance programs and insurance departments help with appeals at no charge, and many hospitals have patient advocates who will chase the insurer for you because the hospital wants to be paid too.
Step 5: Financial assistance and negotiation
Nonprofit hospitals — most hospitals — must have a written financial assistance policy under the tax code, must tell patients about it, and may not take extraordinary collection actions such as lawsuits, liens or credit reporting until they have made reasonable efforts to determine whether the patient qualifies. Eligibility often extends well above the poverty line; some hospitals write off bills for families earning several times it. Ask for the policy and apply, even if the bill is already in collections; the application often stops collection. If you do not qualify, ask for the cash price, which is frequently lower than the insured rate, for a prompt-payment discount, or for a payment plan without interest. Get any agreement in writing before paying.
If the bill goes to collections
A medical debt sent to a collector is subject to the Fair Debt Collection Practices Act: you can dispute it within 30 days of the validation notice and the collector must verify it before continuing. The credit bureaus do not report medical collections under $500, remove them once paid, and wait a year before listing new ones; the federal rule that would have removed medical debt from reports entirely was set aside by a court in 2025, but several states have enacted their own bans on medical debt reporting. A disputed bill — one you have challenged in writing with the provider — should not be reported as delinquent while the dispute is open, and you can say so to the collector and the bureaus.
What does the No Surprises Act protect against?
Balance bills for emergency care, out-of-network providers at in-network facilities and air ambulances; you owe only in-network cost sharing. Ground ambulances are not covered, and you can refuse waivers for scheduled out-of-network care.
What is a good faith estimate?
A written estimate of charges that providers must give uninsured and self-pay patients before scheduled care; a bill $400 or more above it can be disputed through the federal process within 120 days for $25.
How do I appeal a denied claim?
Internal appeal in writing within 180 days with your doctor's support, then binding external review within four months if the denial stands; state insurance departments help without charge.
Can unpaid medical bills hurt my credit?
Less than before: collections under $500 are not reported, paid ones are removed, and new ones wait a year; a 2025 federal rule removing medical debt entirely was vacated, and state laws vary.
Keep every document and every date: the bill, the itemization, the explanation of benefits, your letters and the provider's replies. Disputes are won by the side with the paper. For bills in the thousands, nonprofit patient advocates and medical billing advocates review accounts for a fee or a share of savings.
The Counsel Rights Desk
The Rights Desk writes explainers on consumer, employment, housing and health law for readers without lawyers. Every guide is reviewed by a practicing attorney before publication.
This guide is for general information only and is not legal or medical advice. Appeal deadlines and dispute procedures depend on your plan and state; consult your state insurance department, a consumer assistance program or an attorney about your situation.