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

Prior authorization (also called prior auth, PA, or pre-certification) is a requirement by your health insurance company that you — or your doctor — obtain approval before receiving certain medical treatments, procedures, medications, or services. If your insurer requires prior authorization and you don't get it before receiving care, your claim will almost certainly be denied, even if the treatment is medically necessary.

How Prior Authorization Works

When your doctor recommends a treatment that requires prior auth, here is how the process unfolds:

Step 1: Your provider submits a PA request. The request includes your diagnosis codes (ICD-10), the procedure or medication being requested (CPT or NDC code), clinical notes supporting medical necessity, and the specific plan criteria being met.

Step 2: The insurer or its vendor reviews the request. Many insurers outsource PA to third-party utilization management companies like eviCore, AIM Specialty Health, or Carelon. These reviewers compare the request against clinical criteria — often proprietary guidelines like InterQual or MCG — that are not always publicly available.

Step 3: Approval, denial, or modification. The insurer may approve the full request, approve a modified version (fewer sessions, a different drug tier), or deny it outright. They are required to give you a written denial with the specific reason.

Which Treatments Require Prior Authorization Prior auth requirements vary by plan, but commonly covered services include: MRI and CT scans, specialty drugs, surgery (especially elective procedures), inpatient hospitalization, mental health residential treatment, physical and occupational therapy beyond a set number of visits, durable medical equipment, and certain lab tests. Your plan's Evidence of Coverage document lists all services requiring PA.

How to Get Prior Authorization Approved

The most common reason PA gets denied is incomplete documentation. To maximize approval odds:

• Ask your doctor to include the specific clinical criteria your insurer uses and explicitly address each one in the request.
• Submit peer-reviewed clinical guidelines (like those from specialty medical societies) showing the treatment is standard of care.
• Include your treatment history: prior treatments tried, why they failed, and why this treatment is the next appropriate step.
• Follow up within 48 hours. PA requests are often lost or sitting in a queue with no action taken.

What to Do If Prior Authorization Is Denied

A PA denial is not final. You have the right to appeal, and peer-to-peer reviews have one of the highest overturn rates of any appeal type.

Peer-to-Peer Review: Your doctor calls the insurer's medical reviewer directly to discuss the case. Many PA denials are reversed at this stage — sometimes within the same phone call. Ask your doctor to request a peer-to-peer review immediately after a denial.

Internal Appeal: Submit a written appeal with additional clinical documentation. Request the specific clinical criteria used to deny the request so you can address each criterion directly.

External Independent Review: Complete Guide" class="auto-link">External Review: If the internal appeal fails, you are entitled to independent external review under the ACA (for non-ERISA plans) or your plan documents (for ERISA plans). External reviewers overturn insurer decisions roughly 40% of the time.

Expedited Review: If your condition is urgent, request an expedited PA review. Insurers must respond within 72 hours (or 24 hours for truly urgent cases) rather than the standard 15-day window.

The 2024 CMS Prior Authorization Rule

In January 2024, the Centers for Medicare and Medicaid Services (CMS) finalized a landmark rule affecting Medicare Advantage, Medicaid, and CHIP plans. Key provisions include:

• 72-hour turnaround for urgent PA requests (down from no federal standard).
• 7-day turnaround for standard PA requests.
• Required reasons for denial that cite the specific clinical criteria not met.
• Continuity of care: Insurers must honor PA approvals for an entire course of treatment, not revoke them mid-treatment.
• Electronic PA (ePA): Plans must implement electronic PA systems to speed the process.

These protections apply to government-sponsored plans. Commercial fully-insured plans are subject to state prior auth reform laws, which more than 30 states have passed as of 2026.

What to Do If This Applies to You

1. Ask your provider's office whether they submitted the PA request and when. Get the reference number.
2. Call your insurer and confirm receipt of the PA request and expected decision date.
3. If denied, immediately request a peer-to-peer review — your doctor's staff should handle this, but you need to push for it.
4. Request the specific clinical criteria used in the denial decision. You are entitled to this information.
5. File a written internal appeal if the peer-to-peer fails.
6. Contact your state insurance commissioner if turnaround times are not being met.

Fight Back With ClaimBack

Prior authorization denials feel arbitrary — and often are. ClaimBack helps you build a structured appeal that directly addresses the clinical criteria your insurer used to say no. Our system identifies the right medical evidence, formats the appeal correctly, and gives you a document your doctor can submit with confidence.

Insurers count on patients giving up after the first denial. Don't give up. A well-constructed appeal with the right clinical support overturns prior auth denials every day — and ClaimBack exists to make that process fast and accessible for everyone.

Start My Free Appeal →

Related Reading

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