How to dispute a medical bill: itemized bill, letter and deadlines

To dispute a medical bill, get the itemized bill and your insurer's explanation of benefits, compare them line by line, then send a short written dispute to the billing office that names the exact charges you contest and asks for a corrected statement. Do not pay the disputed part while you wait, keep a log of every contact, and watch the deadlines below: 180 days for an insurer appeal, 120 days and a $25 fee for the federal good faith estimate dispute, and 30 days once a collector sends you a validation notice. Most disputes are won on paperwork, not on arguments.

On this page

• Before you dispute: the two documents you need
• The 8 medical billing errors to look for
• How to dispute a medical bill, step by step
• Dispute letter template
• Worked example: a $2,180 bill that should be $525
• Which deadline applies to you
• If the bill is already in collections
• If the bill is correct but you cannot pay it
• FAQ

Before you dispute: the two documents you need

A medical bill on its own tells you almost nothing. You need two more documents.

The itemized bill. The first statement is usually a summary: one line, one total. Ask the billing office for an itemized statement that lists every service with its billing code (CPT or HCPCS) and the charge for each. You are entitled to it. Under the HIPAA right of access, billing records are part of your "designated record set," and a provider must act on your request within 30 days, with one 30-day extension allowed if they tell you why in writing (45 CFR 164.524; the definition is in 164.501). Any fee must be reasonable and cost-based, so a portal copy should be free.

The explanation of benefits (EOB). Your insurer sends one for every claim. It shows what the provider billed, what the insurer allowed under its contract, what it paid, and what you owe. The bill should match the patient responsibility on the EOB. If the bill arrives first, wait. Paying before the EOB is the most common way people overpay.

If you are uninsured or self-pay, the equivalent is the good faith estimate the provider had to give you before scheduled care under the No Surprises Act (CMS: your medical bill rights). It is the basis for the federal dispute process below.

Billing mistakes are not rare. In the KFF Health Care Debt Survey, 43% of adults said they had received a medical or dental bill they thought contained an error, and 53% of adults with health care debt said the same (KFF). Checking is normal.

The 8 medical billing errors to look for

Put the itemized bill next to the EOB and work through this table. Most disputes come down to two or three of these.

Error	How to spot it	What to ask the billing office
Duplicate charge	The same code and date appear twice, or a bundled service is billed again as a separate line.	"Lines 4 and 9 are the same code on the same date. Please remove one or explain both."
Service you did not receive	A test, drug or supply you do not remember, or a room charge for a night you were not there.	"Please send the chart note or administration record that supports this line."
Wrong code (upcoding)	A longer or more complex visit level than what happened.	"Please check the visit level against the clinical note and recode."
Unbundling	Several lines that are normally one package, such as a lab panel billed as individual tests.	"These codes are normally billed together as one panel. Please rebill."
Balance billing after insurance	An in-network provider charges you the gap between its full charge and the insurer's allowed amount.	"My EOB shows patient responsibility of $X. Please adjust the balance to that figure."
Insurance not applied	Full charge, no insurance payment or adjustment. Often the claim was never filed.	"Please confirm the claim went to [insurer] and send the claim number."
Out-of-network surprise	An emergency visit, or a doctor you did not choose at an in-network hospital, billed at out-of-network rates.	"This falls under the No Surprises Act. Please rebill at the in-network cost share."
Payment not credited	A copay or deposit you paid at the desk is missing from the statement.	"I paid $X on [date], receipt attached. Please apply it and send a corrected balance."

How to dispute a medical bill, step by step

1. Do not pay the disputed amount. Pay any part you agree with and say so in writing. Pay each account or date of service separately so a payment cannot be misapplied.
2. Get the itemized bill and the EOB, then mark the lines you contest using the table above: code, date, amount, reason.
3. Dispute in writing. Portal message, email, or a tracked letter. Phone calls are fine for questions, but the dispute itself needs a paper trail. Use the template below.
4. Keep a contact log. Date, time, name, what was said, agreed next step, reference number.
5. If the error is the insurer's, appeal to the insurer. A wrong EOB or a denied claim means an internal appeal with the insurer, not the provider, within 180 days of the denial notice (HealthCare.gov: internal appeals). Tell the provider in writing that the claim is under appeal and ask them to hold the account.
6. Escalate after 30 days of silence. Hospital patient advocate or ombudsman first. Then your state insurance department (insurer problems) or state attorney general (provider billing problems). For a good faith estimate dispute, use the federal process in the deadlines table. The No Surprises Help Desk is 1-800-985-3059.
7. Get the correction in writing. Ask for a corrected statement, and if the account reached a collector, a letter confirming it was sent in error.

Dispute letter template

Copy this into a portal message, email or letter. One page. Attach copies, never originals.

Subject: Billing dispute, account [number], date of service [date]

To the billing department at [provider name],

I am writing to dispute the following charges on the statement dated [date] for account [number]. I am not refusing to pay what I owe. I am asking for the charges below to be reviewed and corrected before I pay the balance.

1. [Line / code / date], billed $[amount]. Reason: [duplicate of line X / service not received / EOB shows patient responsibility of $Y / claim not submitted to insurer / payment of $Z on [date] not credited].
2. [Line / code / date], billed $[amount]. Reason: [...].

Please send me:
- A corrected itemized statement, or a written explanation of each line above with the supporting record.
- Confirmation that this account is on hold and will not be sent to collections while the dispute is open.

I have attached: [itemized bill, EOB dated ..., receipt for payment of $..., good faith estimate dated ...].

Please reply in writing within 30 days. My contact details are below.

[Name]
[Address, phone, email]

If a debt collector is involved rather than the provider, use the Consumer Financial Protection Bureau's sample letter for disputing a debt instead.

Worked example: a $2,180 bill that should be $525

This is an example with made-up numbers, not a real account. It shows the arithmetic you are checking.

Maria has an outpatient MRI at an in-network imaging center. The first statement says she owes $2,180. She gets the itemized bill and the EOB.

Item	Itemized bill	EOB	Finding
MRI lumbar spine without contrast (CPT 72148)	$1,650	Billed $1,650, allowed $820	Provider charge, not the contract rate
Radiologist read (CPT 72148-26)	$380	Billed $380, allowed $190	Same issue
Contrast agent	$150	Not on claim	She had no contrast. Service not received.
Insurance payment	$0 shown	Insurer paid $484.80	Payment not posted to her account

From the EOB: allowed amount $820 + $190 = $1,010. Maria has $404 of deductible left, then owes 20% coinsurance on the remaining $606, which is $121.20. Patient responsibility: $404 + $121.20 = $525.20. The insurer paid the other $484.80. The EOB shows all of this; she only has to check the bill against it.

Her letter asks for three things: remove the $150 contrast line, post the insurer's payment, and set the balance to the EOB's $525.20, because an in-network center cannot balance bill. The corrected statement comes back at $525.20. The $89 deposit she paid at the desk, which the first statement had also failed to credit, is applied against it, so she pays $436.20 more and her total cost is $525.20 against an original demand of $2,180. No negotiation was needed. Two documents and one letter.

Which deadline applies to you

The clock that matters depends on who sent the bill and whether insurance was involved. Every figure below was checked against the linked official page when this guide was written.

Situation	Deadline or rule	Source
Insurer denied the claim or paid the wrong amount	Internal appeal within 180 days of the denial notice. Insurer decides within 30 days (service not yet received), 60 days (already received) or 4 business days (urgent).	HealthCare.gov
Internal appeal lost	Request an independent external review within 4 months of the final denial. Reviewer decides within 45 days, or 72 hours if expedited.	HealthCare.gov
Uninsured or self-pay, bill is $400 or more above the good faith estimate	Start a patient-provider dispute within 120 calendar days of the bill date. $25 non-refundable fee, credited against what you owe if you win. Provider cannot send the bill to collections while the dispute is open.	CMS
A debt collector contacts you	You have 30 days from the validation notice to dispute in writing. The collector must stop collecting the disputed amount until it responds.	CFPB
You asked for your itemized bill or records	Provider must act within 30 days, one 30-day extension allowed with written reasons.	45 CFR 164.524
Nonprofit hospital bill	No extraordinary collection actions (credit reporting, selling the debt, lawsuits) for at least 120 days after the first post-discharge statement, 30 days' written notice before any, and financial assistance applications accepted for at least 240 days.	IRS, section 501(r)(6)
Credit report	The three bureaus do not report medical collections with an initial balance under $500, remove paid medical collections, and wait one year before an unpaid medical collection appears. These are voluntary bureau policies, not a federal rule.	Equifax, Experian, TransUnion

On the credit report row: a federal rule that would have removed all medical debt from credit reports was vacated by a federal court in July 2025, so the bureaus' voluntary policies are what applies today. Several states have stronger limits of their own.

If the bill is already in collections

A collector's letter does not make a wrong bill right. Reply in writing within 30 days of the validation notice: you dispute the debt and want verification, meaning the original creditor, the itemized amount and proof you owe it. The collector must pause until it sends that. Copy the provider, which can recall the account.

Do not make a "good faith" payment on a disputed collection account; getting money back from a collector is slow. Card disputes exist for billing errors too, and our guide to reasons to dispute a credit card charge covers when they work, but a medical bill is easier to fix at the source. If a wrong or paid debt reaches your credit report, dispute it with each bureau; under the policies above, paid medical collections come off entirely.

If the bill is correct but you cannot pay it

Nonprofit hospitals, which is most US hospitals, must have a written financial assistance policy and must tell you about it before any serious collection action (IRS). Ask by name: "I would like to apply under your financial assistance policy." Income limits vary, and many hospitals give partial discounts well above the poverty line. The hospital must process a complete application for at least 240 days after the first bill, so you can apply after the fact.

For-profit providers have no such duty, but most offer hardship discounts and interest-free plans. Ask in writing: Is there a prompt-pay discount? A hardship discount? What is the longest interest-free plan?

Keep every message plain. Our complaint letter template is a good model for the escalation step, and handing life admin to ChatGPT shows how to brief an AI with your documents so it drafts the letter and follow-ups for you.

FAQ

Can you dispute a medical bill after paying it?

Yes. Paying does not mean you agreed the bill was correct. Send the same written dispute, attach proof of payment, and ask for a refund of the overcharged amount. If you paid by card and the provider will not refund a clear error, a card dispute is a fallback. For insured care, also check whether the insurer processed the claim after you paid, since that often produces a credit you have to ask for.

How long do you have to dispute a medical bill?

There is no single deadline. Insurer appeals must be filed within 180 days of the denial. The federal good faith estimate dispute for uninsured patients must start within 120 days of the bill. A collector's validation notice gives you 30 days to dispute in writing. A provider billing error has no fixed federal deadline, but the sooner you write, the easier it is to stop the account going to collections.

Does disputing a medical bill hurt your credit?

Disputing does not. Ignoring the bill might. The three credit bureaus wait one year before reporting an unpaid medical collection, do not report medical collections under $500, and remove paid ones. During a federal good faith estimate dispute, the provider cannot send the bill to collections at all. Keep your dispute in writing and the account should never reach your report.

What is the No Surprises Act and does it cover my bill?

It is the federal law that stops most surprise out-of-network bills for emergency care, and for care from out-of-network providers at in-network hospitals and surgery centers. It also requires good faith estimates for uninsured and self-pay patients and gives them a dispute process when the bill is $400 or more above the estimate. It generally does not cover ground ambulance services, or care under dental-only, vision-only or short-term plans (CMS: know your rights).

Who do I complain to if the hospital will not fix the bill?

Start with the hospital's patient advocate or ombudsman. If the problem is the insurer, your state department of insurance handles complaints. If the problem is the provider's billing, your state attorney general's consumer protection office does. For surprise bills and good faith estimate problems, call the federal No Surprises Help Desk on 1-800-985-3059 or file a complaint through the CMS medical bill rights site.