Your prior authorization was denied. Here is exactly what to do.

A prior authorization tells you, before a treatment happens, whether your insurer agrees to pay for it. When that pre-approval comes back as a no, it can stall a surgery, a prescription, an imaging study, or a referral. The good news: a prior authorization denied decision is one of the more workable denials to challenge, because it often turns on paperwork, process, or a plan rule rather than a firm judgment that you do not need care. This guide walks through exactly what to do, in the order that matters.

What prior authorization is and why it gets denied

Prior authorization (also called pre-authorization, pre-certification, or pre-approval) is a requirement that your doctor get the plan's sign-off before delivering certain services. Insurers use it to confirm a service meets their coverage criteria. The catch is that a denial at this stage does not always mean the insurer thinks your care is unnecessary. Prior-auth denials are commonly one of these types:

• Administrative or process denials. The request was never submitted, was submitted to the wrong department, was missing a clinical note, or used a code that did not match the documentation. These are frequently fixable once the right paperwork reaches the right reviewer.
• Step therapy (fail first) denials. The plan wants you to try a preferred, usually cheaper, drug or treatment before it will cover the one your doctor ordered.
• Medical-necessity denials. The reviewer decided the service did not meet the plan's clinical criteria. This is an opinion you can rebut with evidence.

You will sometimes see a Claim Adjustment Reason Code on a remittance, and it is worth being precise about them. CO-11, for example, generally signals that the diagnosis is inconsistent with the procedure billed. That is a coding or clinical-justification mismatch, not a missing pre-approval, so do not assume it is the prior-authorization code. Prior-authorization-not-obtained denials are typically carried under a separate administrative reason. The practical takeaway: read the exact words in your denial letter and do not rely on the code alone. If the reason is ambiguous, the next step settles it. You can also look up common codes on our denial codes reference.

Immediate steps the day your denial arrives

Move quickly, because every appeal has a clock. Three things come first.

1. Call the insurer. Use the member services number on your card. Ask three questions: why exactly was this denied, what is the appeal deadline, and what specific documents would change the decision. Write down the date, the representative's name, and a reference number for the call.
2. Get the denial in writing. A verbal reason is not enough. Request the written denial (often called an adverse benefit determination) and the plan's clinical criteria it applied. You are entitled to the reasoning behind the decision, and you will need it to write a targeted appeal.
3. Find and calendar the deadline. The written denial states how long you have to file an internal appeal. Mark it the day the letter arrives. Missing the deadline can forfeit your right to appeal entirely, so treat it as the single most important date in this process.

The role of your prescribing doctor

For prior-auth denials, your doctor's office is your most powerful ally, because the dispute is usually clinical. Two tools are especially effective.

Peer-to-peer review. Many insurers offer a phone conversation between your prescribing physician and the plan's medical reviewer. A clinician explaining the reasoning directly often resolves a denial faster than any letter, because the reviewer can ask questions and get immediate answers. Ask your doctor's office to request one, and do it early, as some plans limit the window. Our guide on the peer-to-peer review explains how to prepare.

Letter of medical necessity. This is a written statement from your physician explaining your diagnosis, what was tried before, why the denied service is the appropriate next step, and what is likely to happen without it. A strong letter ties your specific facts to the plan's own coverage criteria. See our letter of medical necessity guide for what to include and how to structure it.

Step therapy and fail-first denials

If your denial requires you to try a different drug or treatment first, you are facing a step therapy rule. The path forward is a medical exception request, sometimes called a step therapy exception or a fail-first override. Your prescribing doctor asks the plan to waive the requirement, and the request is strongest when it documents one or more of these:

• You already tried the required preferred option, and it failed or was not tolerated. Attach the records that prove it.
• The required option is expected to be ineffective or harmful for your condition, based on your history or clinical factors.
• The required option is contraindicated for you, or you have a documented adverse reaction to it or to a drug in the same class.
• Delaying the prescribed treatment to step through alternatives would put your health at risk.

A step therapy appeal succeeds on documentation. The more specific your doctor is about what was tried, when, and why the prescribed treatment is the right one for you, the harder it is for the plan to keep the denial in place.

Urgent care: the expedited 72-hour appeal

If waiting for a standard appeal would seriously jeopardize your health or your ability to regain function, you do not have to wait. Federal rules guarantee an expedited (fast-tracked) appeal for urgent situations.

Under the Affordable Care Act rules at 45 CFR § 147.136, non-grandfathered health plans must decide an expedited internal appeal as soon as your medical condition requires, and in no case later than 72 hours after receiving the request. If your coverage is an employer-sponsored plan governed by ERISA, the parallel standard at 29 CFR § 2560.503-1 sets the same 72-hour timeline for urgent care claims. To use it, state explicitly that you are requesting an expedited appeal and explain, ideally with your doctor's support, why delay would harm your health. You can also pursue the internal appeal and an external review at the same time when the situation is urgent.

How to write and send the appeal

Your written appeal does not need legal language. It needs to be clear, specific, and tied to the denial reason. A workable structure:

1. Identify yourself and the claim: member ID, claim or authorization number, the service denied, and the date of the denial letter.
2. State plainly that you are appealing, and request expedited review if your situation is urgent.
3. Address the exact reason given. If it was administrative, point to the corrected or missing information. If it was step therapy, reference the medical exception. If it was medical necessity, summarize the clinical case.
4. List the documents you are attaching and refer to them by name so the reviewer can find each one.
5. Ask for a specific outcome: approval of the prior authorization for the requested service.

Attach the denial letter, the original prior-auth request, your letter of medical necessity, relevant clinical notes and test results, and records of any treatments you already tried. Send the appeal by a trackable method such as certified mail with return receipt, or through the insurer's portal if it provides a timestamped confirmation. Keep a complete copy of everything you submit. If you would rather not assemble all of this by hand, our free appeal letter generator drafts a structured, evidence-cited appeal from your denial letter.

If the internal appeal fails: external review

An upheld denial after your internal appeal is not the end. Under 42 USC § 300gg-19 and the ACA rules at 45 CFR § 147.136, most health plans must offer an external review by an independent review organization that has no stake in the outcome. The independent reviewer looks at your case afresh, and its decision is binding on the plan. There are deadlines to request external review once your internal appeal is final, and an expedited external review exists for urgent cases. Our guide on external review and the IRO walks through how to request it and what to expect.

The short version of denied prior auth: what to do

When you are wondering about a denied prior auth what to do next, the sequence is consistent: get the denial in writing, find the deadline, loop in your prescribing doctor for a peer-to-peer review and a letter of medical necessity, file a medical exception if step therapy is the problem, use the expedited 72-hour track if your care is urgent, send a documented appeal by a trackable method, and escalate to external review if the internal appeal does not go your way. A prior authorization appeal rewards speed and specificity more than anything else.