How to Appeal a Health Insurance Denial (And Win)

Quick Answer: Most insurance denials can be appealed — and a meaningful percentage are reversed. You have three main tools: an internal appeal (file within 180 days), a peer-to-peer review where your doctor calls the insurer's medical director, and an independent external review if the internal appeal fails. For urgent care, an expedited appeal must be decided within 72 hours.

Why Denials Happen — and Why Many Are Wrong

Insurance denials fall into a few categories: prior authorization failures, medical necessity disputes, out-of-network issues, coding errors, and coverage exclusions. A significant portion are overturned on appeal — not because the insurer changed its policy, but because the initial denial was a rubber-stamp decision made without adequate clinical review.

The first step after any denial is to read the denial letter carefully. It must state the specific reason for denial and the clinical criteria used. If the reason is vague, request the full clinical guidelines the insurer applied — you are entitled to them.

Step 1: Internal Appeal (File Within 180 Days)

Every insurer regulated under the ACA must offer an internal appeal process. Key rules:

  • You have at least 180 days from the denial notice to file. Check your letter — some plans allow more time.
  • The insurer must decide within 30 days for pre-service (prospective) appeals and 60 days for post-service (retrospective) appeals.
  • A different reviewer — not the person who made the original denial — must review your appeal.
  • You can submit new evidence: clinical notes, peer-reviewed literature, specialist letters, photos, or anything relevant that supports medical necessity.

Your internal appeal letter should include: the claim number, date of service, denial reason, why the denial is incorrect (citing the insurer's own clinical criteria), and supporting documentation from your treating physician.

Step 2: Peer-to-Peer Review — Your Most Powerful Tool

A peer-to-peer (P2P) review is a direct conversation between your doctor and the insurer's medical director. It happens before or alongside the internal appeal and is often the fastest path to reversal.

Why it works: the initial denial is usually made by a nurse reviewer or algorithm, not a physician. When your doctor speaks directly with the insurer's medical director — physician to physician — they can present clinical nuance, patient-specific factors, and evidence that a form-based review cannot capture.

  • Ask your doctor's office to request a peer-to-peer review immediately after the denial — many insurers limit it to within 14–30 days of the denial.
  • Your doctor should prepare: the clinical rationale, relevant guidelines (UpToDate, specialty society recommendations), prior treatment failures, and patient-specific factors that make this the appropriate treatment.
  • Studies and insurer data show P2P reviews reverse denials at approximately a 50% rate.

Step 3: Expedited Appeal for Urgent Care (72-Hour Decision)

If waiting for the standard appeal timeline would seriously jeopardize your health, you are entitled to an expedited appeal. The insurer must decide within 72 hours.

Expedited appeals apply when:

  • You are currently hospitalized and the insurer is denying continued inpatient stay.
  • You need a procedure or medication urgently and delay could cause serious harm.
  • Your physician certifies that the standard timeframe is medically inappropriate.

File the expedited appeal in writing, labeled clearly as "Expedited Appeal — Urgent Medical Situation," and have your physician include a letter stating the urgency and potential harm from delay.

Step 4: External Review (Independent Organization)

If your internal appeal is denied, you have the right to an independent external review. An accredited, independent organization — not the insurer — reviews the decision fresh.

  • You must file for external review within 4 months of the final internal denial.
  • The external reviewer's decision is binding on the insurer. If they reverse the denial, the insurer must cover the service.
  • External review is free to you for ACA-regulated plans.
  • For employer self-funded plans (often large employers), the federal external review process applies. For state-regulated plans, your state's process governs.

Request external review through your insurer — they are required to provide the process. You can also initiate it through your state insurance department for state-regulated plans.

Step 5: State Insurance Commissioner Complaint

File a complaint with your state insurance commissioner whether or not you are pursuing an appeal. This creates a regulatory record, sometimes prompts the insurer to reconsider proactively, and protects other patients if a denial practice is systemic.

Find your state department at naic.org/state_web_map.htm. Your complaint should include: the denial letter, your appeal, the clinical justification, and a clear statement of what you are asking the commissioner to investigate.

Building a Strong Appeal: What to Include

  • A letter of medical necessity from your treating physician — this is the single most important document. It should address the insurer's specific denial criteria directly.
  • Peer-reviewed clinical literature supporting the treatment as appropriate for your diagnosis.
  • Documentation of prior treatment failures — if the insurer denied a medication because a cheaper alternative exists, show that you tried the cheaper option and it failed.
  • The insurer's own clinical coverage policy — request it by name, read it carefully, and point to the criteria you meet.
  • Your treatment history — dates, diagnoses, prior authorizations, prior approvals for similar services.

Common Denial Reasons and How to Counter Them

  • "Not medically necessary": Have your doctor write a detailed letter citing clinical guidelines and patient-specific factors. Request a peer-to-peer review.
  • "Experimental or investigational": Research whether the treatment is approved by the FDA, recommended by specialty society guidelines, or covered by Medicare. Any of these counter the "experimental" label.
  • "Prior authorization not obtained": If your doctor's office forgot to get auth, they may be able to obtain a retrospective authorization. If they did request auth and the insurer lost or denied it improperly, document the request with dates.
  • "Out-of-network provider": Check whether the NSA applies (emergency care, out-of-network provider at in-network facility). If not NSA-protected, request a "single case agreement" allowing the out-of-network provider to be treated as in-network for this service.
  • "Coding error": Contact the provider's billing office. A resubmission with the corrected code often resolves this without a formal appeal.

Timeline Summary

  • Immediately: Request peer-to-peer review, request clinical criteria used for denial.
  • Within 14–30 days: File internal appeal with full supporting documentation.
  • Within 4 months of final denial: File for independent external review.
  • Any time: File state insurance commissioner complaint.