Denied for Missing Prior Authorization? What to Do Next

Written by Aptiva Health Editorial Team · Reviewed by Taylor Sorrels, Esq. and Crystal Brake, RCM Director · Editorial & review standards · How we research

Prior authorization means your health plan must approve some care before you get it. It is also called pre-authorization or pre-certification. If the plan has no approval on file, it may deny the claim afterward, even if the care was right for you.

This denial is often about paperwork and timing, not medicine. That is good news: it can often be fixed. This guide explains how. It is part of the Coverage & Appeals Center. For the basics, see how prior authorization works.

What the letter says vs. what it means

The fix depends on which one you have. Call the plan and ask exactly what is missing. Write down the answer and a reference number.

Rules that changed in 2026

A federal rule called CMS-0057-F changed prior authorization for many plans starting January 1, 2026 (CMS: CMS-0057-F fact sheet). It applies to:

• Medicare Advantage plans
• Medicaid and CHIP (including managed care plans)
• Plans sold on the federal ACA Marketplace (specific-reason rule only)

For these plans, the rule says:

• Urgent requests must be decided within 72 hours.
• Standard requests must be decided within 7 calendar days.
• When they deny a request, they must give a specific reason.
• They must publish data about their prior authorization decisions in 2026.
• They must offer electronic prior authorization systems by January 1, 2027.

Many large insurers also made voluntary promises in June 2025. These include clearer denial explanations and a 90-day transition period for prior authorizations when you switch plans during treatment, starting in January 2026 (CMS: industry pledge, June 23, 2025). These are promises, not laws, so ask your plan how it applies them.

If you have Traditional Medicare, a separate model called WISeR began testing AI-assisted prior authorization in six states in 2026. Kentucky and Indiana are not part of it (CMS: WISeR Model).

How to fix a missing prior authorization denial

1. Find out whether a request was sent. Call the provider’s office and ask if they requested approval, when, and what the reference number was.
2. If a request was sent, get proof. Ask the provider’s office for the submission record, fax confirmation or portal screenshot.
3. If no request was sent, ask about retro-authorization. Some plans accept a request after the care. Ask the provider’s office to request it with the medical reasons.
4. Check the details. Make sure the approved service code, number of visits and dates match the claim. A mismatch can look like “no authorization.”
5. Appeal with the medical reasons. If the plan still denies, file an internal appeal. Explain why the care was needed and attach your clinician’s letter and records.
6. Ask for external review if needed. If the denial was based on medical judgment, you may be able to ask for an outside review (45 CFR 147.136(d); KRS 304.17A-600; IC 27-8-29-12).

Who is responsible?

It depends on your plan and the provider’s contract. When a provider is in network, the provider’s office is often responsible for getting approval. In some contracts, the in-network provider cannot bill you for a service the plan denied only because the office didn’t get approval.

If you saw an out-of-network provider, you may be responsible for getting the approval yourself. Check your plan documents.

Ask the provider’s billing office directly: “Am I responsible for this bill if the denial was for missing authorization?” Get the answer in writing if you can.

Sample appeal letter

[Your name]
[Your address] · [Your phone] · [Your email]

[Date]

[Plan name] — Appeals Department
[Address or fax from your denial letter]

RE: Appeal of denial for missing prior authorization
Member name: [Name]
Member ID: [Number]
Claim / reference number: [Number]
Service: [Service] on [date]
Provider: [Name]
Date of denial letter: [Date]

To the Appeals Department:

I am appealing your denial of [service] on [date] for "[copy the exact reason]."

[Choose one:]
- A prior authorization request was submitted on [date] (reference [number]). Proof of submission is enclosed. Please process the claim under that request.
- The service was needed before approval could be obtained because [reason, e.g., urgent symptoms]. I ask you to review the medical necessity of the care and approve it retroactively.

Enclosed:
- Proof of the prior authorization request (if any)
- Letter of medical necessity from [clinician]
- Medical records from [dates]
- Your denial letter

Please reverse the denial. If you do not, please explain the specific reason in writing and tell me how to request an external review.

Sincerely,
[Signature]
[Printed name]

Deadlines

See the Kentucky and Indiana guides for state details. Self-funded employer plans use the federal external review process.

When to escalate

• If the plan won’t tell you what is missing, ask for the specific reason in writing. Plans covered by CMS-0057-F must give a specific denial reason since 2026.
• If you are stuck between the plan and the provider, contact your state Department of Insurance: Kentucky (800) 595-6053 (KY DOI Consumer Protection) or Indiana (800) 622-4461 (IDOI Consumer Services).
• If the real issue is whether the care was needed, see denied as “not medically necessary”.

How to avoid this denial next time

Most prior authorization problems can be prevented with a few questions before your appointment:

• “Does this service need prior authorization under my plan?” Ask the plan and the provider’s office.
• “Who is requesting it, and when?” Get a name and a date.
• “Has it been approved?” Ask for the approval or reference number before your visit.
• “What exactly was approved?” Check the service, the number of visits, the body part or level, and the dates.
• “When does it expire?” Schedule the care inside the approved dates.
• “Am I switching plans soon?” If so, ask your new plan how it handles approvals from your old one. Many insurers promised a 90-day transition period starting in 2026 (CMS: industry pledge).

Keep the approval number with your appointment details. If a claim is later denied, that number is your best evidence.

Urgent and emergency care

Emergency care is handled differently: most health plans must cover emergency services without prior authorization (45 CFR 149.110). You should never delay emergency care to get approval. Call 911 in an emergency.

If the care is urgent but not an emergency, ask the provider to request an urgent prior authorization. Since 2026, Medicare Advantage and Medicaid plans must decide urgent requests within 72 hours.

Get specific help

Prior authorization is common for imaging, therapy and injections. See how to get these covered:

• MRI
• Physical therapy
• Epidural steroid injection