How long do I have to file an internal appeal?

Under federal rules for ACA-compliant plans, you generally have at least 180 days from the date of the denial notice to file an internal appeal. Your plan documents will specify the exact deadline, which may be shorter than the federal maximum for some older or grandfathered plans. Do not delay — missing the deadline can forfeit your appeal rights.

How long does the insurer have to respond to my internal appeal?

For urgent (expedited) appeals, the insurer must respond within 72 hours. For standard prior authorization appeals, most plans must respond within 30 days. For post-service claim appeals, the timeframe is typically 60 days. Some states impose stricter timelines — your state insurance commissioner's website will have current rules for your state.

Can my doctor help with the appeal?

Yes, and their involvement is often critical. Ask your physician to write a letter of medical necessity that specifically addresses the insurer's reason for denial. If the denial cited specific clinical criteria, the letter should directly respond to those criteria with clinical documentation from your records.

What if my appeal is denied?

If the internal appeal is denied, you generally have the right to request an external review by an Independent Review Organization (IRO). The external review is independent of your insurer, is usually free to you, and is binding on the insurer if decided in your favor. See the External Review guide for details.

Can I appeal a denial for a service I already received?

Yes. Post-service appeals apply to claims for services you have already received that were denied. The process is similar to pre-service appeals, though the timeframes for insurer response may differ. The appeal is still worth filing because a successful post-service appeal can result in the insurer paying a claim they initially denied.

What is the difference between a grievance and an appeal?

A grievance is a complaint about the quality of care or service you received. An appeal is a formal request for the insurer to reconsider a coverage decision — a denial of a prior authorization, a denial of a claim, or a coverage limitation. They are handled through separate processes, though both are required to be available to members under federal law.

Should I file an appeal if I cannot pay the bill?

Yes. An appeal is separate from your obligation to pay. Filing an appeal does not prevent you from also inquiring about the hospital's financial assistance program or payment plans. If the appeal succeeds, the insurer pays what was denied, which may eliminate or reduce your balance.

What if I am on Medicare or Medicaid?

Medicare and Medicaid have their own appeals processes, which differ from commercial insurance appeals. Medicare beneficiaries can contact 1-800-MEDICARE and request a redetermination from the Medicare Administrative Contractor. Medicaid beneficiaries have the right to a fair hearing through their state agency. The process described in this guide applies primarily to commercial and employer-sponsored insurance.

US Healthcare · Bills and Rights

Appealing a Prior Authorization Denial

A step-by-step guide to filing an internal appeal after your insurer denies a prior authorization or claim — what to gather, what timeframes apply, and how to build the strongest possible case.

Who this is for

Patients or caregivers who have received a written denial from their health insurer for a prior authorization, a claim, or a service — and who want to understand how to challenge it through the internal appeal process.

When your health insurer denies coverage for a service, medication, or procedure, that denial is not the final word. Federal law and most state laws give you the right to challenge the decision through a formal process. Understanding how that process works — and what documentation strengthens your case — can make the difference between getting the care covered and paying out of pocket.

This guide covers the internal appeal: the first required step before external review becomes available. For what happens if the internal appeal is denied, see the External Review guide.

Understanding your denial notice

Every denial must be communicated to you in writing. Your denial notice is the starting point for any appeal. Before you do anything else, read it carefully and look for:

The specific reason for denial. Insurers are required to state the reason for a denial in plain language. Common reasons include: not medically necessary, excluded benefit, step therapy requirements not met, prior authorization not obtained, out-of-network provider, and clinical criteria not met.
The specific clinical criteria or plan provision cited. The notice should reference the section of the plan document, the CMS criterion, or the clinical guideline that the insurer used to make its decision.
Your appeal rights and deadlines. Federal rules require the notice to tell you how to appeal, where to send the appeal, and the deadline for filing.
Your right to request documents. You are entitled to request free copies of the clinical criteria, plan documents, and any other information the insurer used to make the decision.

Request those documents before you build your appeal. You cannot respond to criteria you cannot see.

Gathering your documentation

A strong internal appeal is built on documentation. Before writing your appeal letter, gather:

A copy of the denial notice
Your Explanation of Benefits (EOB) for any claim that was denied
Your physician’s medical records relevant to the denied service
Your plan’s Summary of Benefits and Coverage and the section of the plan document cited in the denial
Any clinical guidelines or criteria the insurer says the service did not meet
Published medical literature supporting the necessity of the prescribed treatment (your physician can help identify this)
A letter from your physician — ideally specifically addressing the insurer’s denial rationale

Filing an internal appeal: step by step

Note the deadline. Your denial notice will state the appeal deadline. For most ACA-compliant plans, you have at least 180 days. Act before that date.
Write your appeal letter. Address the specific reasons in the denial notice. Do not just say the decision was wrong — explain why, with reference to your medical records and plan terms.
Include your physician’s letter. A treating physician’s statement of medical necessity is often the most persuasive document in an appeal.
Attach supporting documentation. Include relevant medical records, test results, and any published clinical evidence supporting the treatment.
Send the appeal to the correct address. Use the address listed in your denial notice for appeals — it may differ from your regular claims address.
Send via certified mail or with tracking. Keep proof that the insurer received your appeal and the date it arrived.
Follow up within the timeframe. The insurer is required to respond within set timeframes (see table below). Follow up if you have not received a decision by the expected date.

Timeframes insurers must meet

Federal rules set minimum timeframes for insurer decisions on internal appeals. Many states impose stricter deadlines.

Type of appeal	Insurer must decide within
Urgent / expedited (pre-service)	72 hours
Standard pre-service (before receiving care)	30 days
Post-service (after receiving care)	60 days
Concurrent review (ongoing care)	Per plan terms; expedited available if urgent

Request an expedited appeal if your physician believes that waiting for a standard decision could seriously harm your health. Document the clinical urgency in both your physician’s letter and your own appeal letter.

What strengthens an appeal

Insurance companies deny claims and prior authorizations using clinical criteria — often based on guidelines from medical specialty societies or internal criteria they develop. The most effective appeals address those specific criteria head-on.

Direct response to the denial reason. If the insurer said the service was not medically necessary because of criterion X, your appeal should explain why your case meets criterion X.
Peer-reviewed clinical support. Published guidelines from relevant medical specialty societies or peer-reviewed studies can carry significant weight.
Your specific medical history. A denial based on “step therapy not completed” should be countered with documentation showing why earlier steps were contraindicated, tried and failed, or otherwise inappropriate for your situation.
Physician peer-to-peer. Some insurers offer a peer-to-peer review where your physician speaks directly with the insurer’s medical reviewer. Ask whether this is available and encourage your physician to request it, as it can sometimes resolve a denial before a formal appeal is needed.

Documents and terms you’ll see

During the internal appeal process, you will encounter the following on correspondence, forms, and insurer communications:

Explanation of Benefits (EOB) — the statement showing how a claim was processed; the denial line on your EOB is a key document and should be attached to your appeal

Medical necessity — the standard your insurer is applying to evaluate whether the service is covered; your appeal should demonstrate that the service meets this standard under your plan’s definition

Internal appeal — the required first step before external review; the denial notice will describe the internal appeal process and direct you to the correct submission address

Expedited appeal — the accelerated track for urgent situations; request it explicitly in writing and have your physician document why the standard timeframe creates risk of serious harm

Denial notice — the written denial explaining the reason for the decision and your rights; federal rules require it to be in plain language and to cite the specific basis for the denial

For more on the overall prior authorization process, visit the Prior Authorization and Referrals guide. If your internal appeal is denied, the next step is External Review.

Key terms

Term	Plain meaning	Glossary
Internal appeal	The first required step to contest an insurer's denial — a review conducted by the insurer itself before the patient can access external review	→
Denial notice	The written communication from your insurer explaining that a prior authorization, claim, or service has been denied, including the reason and your appeal rights	→
Explanation of Benefits	A statement from your insurer showing how a claim was processed — which charges were covered, what was denied, and what you owe	→
Expedited appeal	An accelerated internal appeal available when waiting for a standard decision could seriously jeopardize your health or ability to regain maximum function	→
Medical necessity	The insurer's standard for determining whether a service is appropriate, reasonable, and required for the diagnosis or treatment of your condition	→

Common questions

How long do I have to file an internal appeal?: Under federal rules for ACA-compliant plans, you generally have at least 180 days from the date of the denial notice to file an internal appeal. Your plan documents will specify the exact deadline, which may be shorter than the federal maximum for some older or grandfathered plans. Do not delay — missing the deadline can forfeit your appeal rights.
How long does the insurer have to respond to my internal appeal?: For urgent (expedited) appeals, the insurer must respond within 72 hours. For standard prior authorization appeals, most plans must respond within 30 days. For post-service claim appeals, the timeframe is typically 60 days. Some states impose stricter timelines — your state insurance commissioner's website will have current rules for your state.
Can my doctor help with the appeal?: Yes, and their involvement is often critical. Ask your physician to write a letter of medical necessity that specifically addresses the insurer's reason for denial. If the denial cited specific clinical criteria, the letter should directly respond to those criteria with clinical documentation from your records.
What if my appeal is denied?: If the internal appeal is denied, you generally have the right to request an external review by an Independent Review Organization (IRO). The external review is independent of your insurer, is usually free to you, and is binding on the insurer if decided in your favor. See the External Review guide for details.
Can I appeal a denial for a service I already received?: Yes. Post-service appeals apply to claims for services you have already received that were denied. The process is similar to pre-service appeals, though the timeframes for insurer response may differ. The appeal is still worth filing because a successful post-service appeal can result in the insurer paying a claim they initially denied.
What is the difference between a grievance and an appeal?: A grievance is a complaint about the quality of care or service you received. An appeal is a formal request for the insurer to reconsider a coverage decision — a denial of a prior authorization, a denial of a claim, or a coverage limitation. They are handled through separate processes, though both are required to be available to members under federal law.
Should I file an appeal if I cannot pay the bill?: Yes. An appeal is separate from your obligation to pay. Filing an appeal does not prevent you from also inquiring about the hospital's financial assistance program or payment plans. If the appeal succeeds, the insurer pays what was denied, which may eliminate or reduce your balance.
What if I am on Medicare or Medicaid?: Medicare and Medicaid have their own appeals processes, which differ from commercial insurance appeals. Medicare beneficiaries can contact 1-800-MEDICARE and request a redetermination from the Medicare Administrative Contractor. Medicaid beneficiaries have the right to a fair hearing through their state agency. The process described in this guide applies primarily to commercial and employer-sponsored insurance.

Sources

Last reviewed: September 2026

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