The most important number in the denial letter may be the deadline, not the amount billed. For ACA-compliant plans, you generally have 180 days from the denial to file an internal appeal. Other plan types (including Medicare, Medicaid, and certain employer plans) may use different procedures and deadlines, so follow the exact date and instructions in your denial notice.
Once an ACA-compliant internal appeal is filed, the insurer generally must decide within about 30 days for a service not yet received (pre-service) and about 60 days for a service already received (post-service) [1]. For an urgent internal appeal, the final decision must come as quickly as the medical condition requires and, per HealthCare.gov, no later than four business days after the request is received. The decision may initially be delivered verbally, but written notice must follow within 48 hours of that verbal decision. An expedited external review is a separate process, generally decided within 72 hours. You can file using the insurer’s forms or by writing with your name, claim number, and insurance ID number, plus any documents you want considered.
What to include in an appeal letter
Do not write a long emotional letter. Answer the exact denial reason and attach the evidence that fixes it: a formal appeal letter that names the claim and states plainly why the denial is wrong, a Letter of Medical Necessity from your treating physician, supporting medical records, and any published clinical guidelines behind the treatment.
How to challenge a medical necessity denial
If the letter says “not medically necessary,” your opinion is not the strongest evidence; your doctor’s documentation is. Include a detailed Letter of Medical Necessity from your treating physician explaining why the treatment is appropriate for your condition, supported by your medical records and published clinical guidelines. Detailed physician documentation and relevant guidelines can strengthen the appeal by directly addressing the insurer’s medical-necessity criteria, although they do not guarantee the denial will be overturned.
Ask whether your doctor can request a peer-to-peer review
A doctor-to-doctor call can sometimes move faster than another round of paperwork. For medical-necessity and prior-authorization denials, your treating doctor can often request a peer-to-peer review, a direct conversation with the insurer’s clinical reviewer about why the treatment is needed.
A peer-to-peer review may have a short request window and may not replace the formal appeal deadline. Ask the insurer whether requesting one pauses, extends, or has no effect on the deadline for the written appeal. Unless the plan confirms otherwise in writing, keep preparing the formal appeal so you do not miss your deadline waiting for the call.
How to challenge a prior authorization denial
Some prior-authorization denials are procedural and may be resolved by supplying the missing approval, referral, or supporting records. Others involve medical-necessity or coverage criteria and may require a clinical appeal. Confirm the insurer’s stated reason before choosing the response.
How to fix coding and paperwork denials
When the denial is a coding or clerical error, the first practical step is often to contact the provider’s billing office: identify the correct code, supply the missing information, and ask them to correct and rebill. A formal appeal may still be needed if the insurer keeps the denial after the correction.
Step 5: Request an external review
If the insurer denies the appeal again, the next review is conducted by an independent organization that was not involved in the insurer’s original decision. If the denial is eligible for external review, your case goes to an Independent Review Organization (IRO). Under the Affordable Care Act, the IRO’s decision is binding on the insurer: if all or part of the denial is overturned, the insurer must follow the reviewer’s decision, which may require it to authorize the service, cover the treatment, or reprocess and pay the claim.
You generally have about four months (120 days) from the final internal denial to request external review. Standard external reviews are decided within about 45 days, and expedited reviews within 72 hours for urgent cases. The HHS-administered process is free; some state or issuer-contracted processes may charge a filing fee of no more than $25. Check the instructions in your denial notice. You may also submit new evidence at this stage.
Which denials qualify for external review?
Not every denial is eligible. External review commonly covers eligible denials involving medical judgment, medical necessity, experimental or investigational treatment, and certain rescissions of coverage. A routine out-of-network denial based solely on plan terms may not qualify for standard external review. Emergency-care, network-adequacy, and surprise-billing disputes may follow separate federal or state procedures, so use the process identified in your denial notice.
Four common denial reasons and how to counter each
| Denial reason | What it usually means | Evidence or next step to consider |
|---|---|---|
| Medical necessity | The plan determined the service did not meet its medical-necessity criteria | Letter of Medical Necessity plus published clinical guidelines; ask about a peer-to-peer review |
| Coding or paperwork error | Wrong code, missing information, clerical mistake | Correct the code or supply the document; ask the provider to rebill |
| Prior authorization | Required approval was missing or unrecorded | Provide the authorization or records showing it was met |
| Experimental or investigational | The insurer deems the treatment unproven | Studies and specialist support showing accepted use for your condition |
Who regulates your plan?
Where to turn for help depends on your plan type. A Marketplace or other fully insured plan is generally overseen by your state insurance department and may also be subject to federal consumer-protection rules. A self-funded employer plan is generally governed by ERISA and overseen by the U.S. Department of Labor, although other laws may also apply. Medicare and Medicaid use their own appeal systems: Medicare through its redetermination and appeal levels, Medicaid through your state’s process. Knowing which applies tells you whose deadlines and procedures to follow.
What happens to the bill (and collections) during an appeal?
The appeal and the bill are two separate problems, and ignoring either one can create a new headache. Filing an appeal does not automatically pause the provider’s bill or stop collection activity, so handle them in parallel. Contact the provider’s billing office, tell them the claim is under appeal, and ask whether they can place the account on hold while the appeal is pending. Request written confirmation if they agree. An oral promise from a billing representative may not prevent automated collection activity. Ask about financial assistance at the same time, including whether applying pauses collection activity and whether assistance can be applied to the disputed bill. Medical-debt reporting practices are changing and may depend on the applicable law, the credit bureau, the debt amount, and timing, so check the current rules rather than assuming the debt will or will not appear on your credit report. Keep a call log:
| Date | Organization | Representative | Reference number | What was discussed | Promised next step | Deadline |
|---|---|---|---|---|---|---|
Can you negotiate the medical bill?
Yes. Separate from the insurance appeal, you can often negotiate the bill itself: ask for an itemized bill, question charges that look wrong, and ask about a discount or a payment plan. Tax-exempt nonprofit hospitals generally must maintain a written financial assistance policy, although eligibility and available discounts vary [2], so ask the billing office for their policy. Negotiating the bill and appealing the denial are two separate tracks, and you can pursue both.
When a medical billing advocate can help
A medical billing advocate reviews bills, spots errors, and negotiates on your behalf. It can be worth considering when the bill is very large, the coding is complex, several providers are involved, the insurer and hospital keep pointing at each other, or you have resubmitted more than once without success. Advocates charge fees (sometimes a percentage of what they save you), so weigh the cost against the amount in dispute.
When legal help may be appropriate
Many appeals can begin without a lawyer, especially when the issue is a coding error or a missing document. Legal help is worth considering for high-cost treatment that stays denied, complex employer-plan (ERISA) issues, urgent care that keeps being refused, an insurer that will not honor a binding external-review decision, repeated violations of your plan terms, or a denial that could cause serious harm to your health. In those situations, an attorney who handles health insurance denials may help.
Free consumer assistance programs
You do not have to do this alone. Some states run a Consumer Assistance Program that will explain your denial and can file an appeal for you at no cost, and nonprofits and patient-advocacy groups offer similar help. Because the help is free, there is little reason not to use it if the process feels overwhelming.
Your appeal timeline at a glance
- Day 0: Denial arrives. Note the reason and the deadline in the letter.
- By your notice’s deadline (often 180 days): File the internal appeal with your insurer.
- ~30 days / 60 days / 4 business days: Insurer decides (pre-service / post-service / urgent internal).
- If upheld, within ~120 days: Request external review, for eligible denials.
- ~45 days (or 72 hours if urgent): The independent reviewer issues a binding decision. If overturned in whole or part, the insurer must follow it.
Before you appeal: checklist
- Read the denial letter and identify the exact reason.
- Confirm the claim was denied, not just rejected for a fixable error.
- Note both deadlines (the internal deadline in your notice, and ~120 days for external review of eligible denials).
- Gather the denial notice, EOB, plan documents, and medical records; request your claim file.
- Ask the provider to correct and rebill if the issue is coding or paperwork.
- Get a Letter of Medical Necessity, and ask about a peer-to-peer review, if the denial is about necessity.
- Write an appeal letter that answers the specific denial reason.
- Send it by the required method and keep proof of submission.
- Contact the billing office about a hold (in writing) and about financial assistance.
- Keep copies and a call log; ask your state Consumer Assistance Program for free help if needed.
- If the internal appeal fails and the denial is eligible, request external review.
A denial may not be the final coverage decision, but overturning it requires attention to the stated reason, supporting evidence, and every applicable deadline. Confirm whether the problem can be corrected and resubmitted, file the formal appeal when required, and preserve written records of every document and conversation.