What Is Prior Authorization Denied: How to Appeal" class="auto-link">Prior Authorization and Why Was I Denied?

Prior authorization (also called pre-authorization, pre-approval, or pre-certification) is a requirement by your health insurer that you get approval before receiving certain services, procedures, medications, or tests. If you or your provider skips this step — or if the insurer denies the request — the resulting claim may not be covered.

Why Insurers Require Prior Authorization

Insurers use prior authorization to control costs and ensure that services meet their criteria for medical necessity before they're delivered. In theory, this is supposed to prevent unnecessary or wasteful care. In practice, critics argue it often creates barriers to medically needed treatment and leads to delays, denials, and worse patient outcomes.

Common services that typically require prior authorization:

• Surgeries and inpatient hospital stays
• Advanced imaging (MRI, CT, PET scans)
• Specialty medications and biologics
• Specialty care referrals (in HMO plans)
• Durable medical equipment (wheelchairs, CPAP machines)
• Behavioral health and substance use treatment

Why Was My Prior Authorization Denied?

The most common reasons a prior authorization is denied include:

1. Not medically necessary: The insurer's clinical reviewer determined the service doesn't meet their criteria for medical necessity based on their own guidelines (often InterQual or Milliman MCG).
2. Step therapy not completed: The insurer requires you to try and fail cheaper alternatives first (for example, generic medications) before approving the treatment your doctor recommended.
3. Documentation incomplete: Your doctor's request didn't include the clinical information the insurer needed to make a determination.
4. Wrong plan level: Some services require referral from a primary care physician before authorization can be granted (common in HMOs).
5. Not a covered benefit: The service may simply not be covered under your plan, regardless of medical necessity.
6. Coding issues: The authorization request used a different procedure or diagnosis code than what was intended.

Appealing a Prior Authorization Denial

A PA denial is absolutely appealable. Here's how to approach it:

Immediate step — peer-to-peer review: Your doctor can typically request a direct conversation with the insurer's reviewing physician within 2–5 business days of the denial. This call is highly effective and reverses many decisions before a formal appeal is filed.

Formal internal appeal: Submit a written appeal with:

• A physician letter of medical necessity that directly addresses the insurer's stated denial reason
• Clinical documentation: treatment notes, lab results, imaging reports, specialist recommendations
• Evidence from published clinical guidelines (NCCN, AHA, AAP, etc.) that support the requested treatment
• Evidence of failed alternatives if step therapy was the denial reason

External Independent Review: Complete Guide" class="auto-link">External review: If your internal appeal fails, request external review by an IROs) Explained" class="auto-link">Independent Review Organization. PA denials based on medical necessity are among the most frequently overturned categories at external review.

Legislative Changes

Federal and state legislators have increasingly targeted prior authorization requirements. Many states have passed PA reform laws that:

• Require insurers to make decisions within specific timeframes
• Mandate continuity of authorization when you change plans
• Limit PA requirements for certain standard treatments
• Require "gold carding" (exempting doctors with high approval rates from PA requirements)

At the federal level, the ACA requires expedited PA decisions (within 72 hours) for urgent cases.

Fight Back With ClaimBack

Prior authorization denials are often reversible with the right documentation. ClaimBack helps you build a complete appeal package and coordinates with your physician's office to maximize your chances.

Start your appeal at ClaimBack

Related Reading

• What Is Medical Necessity?
• Common Reasons Insurance Claims Are Denied
• How to Write an Insurance Appeal Letter