What is a medical necessity denial?

A medical necessity denial means your insurance company claims the treatment your doctor ordered did not meet its clinical criteria. This does not mean your doctor was wrong — it means the insurer disagreed. You have the legal right to appeal.

Can I appeal a medical necessity denial?

Yes. You have a legal right to appeal any health insurance denial. Studies show over 40% of appeals are overturned when properly submitted. Most plans give only 30 to 180 days to file — act quickly.

How long do I have to appeal a health insurance denial?

Appeal deadlines are typically 30, 60, or 180 days from the denial letter date. Missing this deadline permanently forfeits your right to appeal. Check your denial letter or call your insurer immediately.

Is this template attorney-drafted?

Yes. This appeal letter template was drafted by an attorney with over a decade of insurance law experience. It is editable, includes a video tutorial, and is available as an instant download.

Why was my claim denied for out-of-network care?

Insurance companies deny out-of-network claims when the provider is not in their approved network. Many of these denials are wrongful — especially when care was urgent, when no in-network provider was reasonably available, or when you had no choice of provider in an emergency.

Can I appeal an out-of-network insurance denial?

Yes. You have the right to appeal, particularly if care was medically urgent, no in-network alternative was available, or the insurer failed to properly apply the No Surprises Act or state network adequacy rules.

What is the No Surprises Act?

The No Surprises Act protects patients from surprise bills for emergency care and for non-emergency care at in-network facilities by out-of-network providers when you had no meaningful choice of provider.

My insurance says my treatment is not covered — can I appeal?

Yes. Even when an insurer says a treatment is not covered or a policy exclusion applies, you can appeal. Many of these denials are based on ambiguous policy language or outright errors. An appeal forces the insurer to justify its reading of the policy.

What is a policy exclusion denial?

A policy exclusion denial means the insurer claims a specific clause in your policy excludes the treatment you received. These exclusions must be clearly stated — if the insurer cannot point to exact policy language, the denial may be wrongful and appealable.

Can I appeal a prior authorization denial?

Yes. You can appeal a prior authorization denial whether prospective, concurrent, or retrospective. Even if authorization was not obtained before care, you may have valid grounds — especially if care was urgent or the insurer's authorization process was unclear.

What if I had an emergency and could not get prior authorization?

Emergency care cannot legally require prior authorization. Cite the Emergency Medical Treatment and Labor Act (EMTALA) and your state emergency care laws in your appeal. Federal and state law require insurers to cover emergency stabilization regardless of prior authorization status.

How fast must insurers respond to a prior authorization appeal?

For urgent or ongoing care, you qualify for an expedited appeal — insurers must respond within 72 hours. For standard prior authorization appeals, deadlines are typically 30 days for pre-service decisions.

Can I appeal an experimental treatment denial?

Yes. Experimental or investigational treatment denials are among the most successfully appealed when the right evidence is presented. Insurers often apply outdated clinical criteria. A strong appeal presents published studies, clinical guidelines, and your physician's statement.

What evidence do I need to appeal an experimental treatment denial?

The strongest appeals include peer-reviewed clinical studies, published guidelines from major medical societies such as the AMA or ASCO, your treating physician's letter explaining why treatment is appropriate for your specific condition, and documentation showing the insurer's criteria are outdated.

What does denial code PR-1 mean?

PR-1 means Deductible Amount — Patient Responsibility. The insurer is applying the charge to your deductible. However, PR-1 denials are frequently incorrect — caused by calculation errors, timing issues, incorrect coordination of benefits, or provider and payer miscommunication.

Can I appeal a PR-1 deductible denial?

Yes. You can appeal if your deductible has already been met, if claims were processed in the wrong order, if there was a coordination-of-benefits error, or if the insurer incorrectly tracked your deductible accumulation.

What does denial code CO-167 mean?

CO-167 means the diagnosis code submitted does not justify the procedure billed. CO-167 denials are often caused by coding errors at the provider's billing office — not by a genuine lack of medical necessity.

How do I appeal a CO-167 diagnosis procedure mismatch denial?

Contact your provider's billing department to verify which codes were submitted. If codes were incorrect, ask the provider to resubmit. If codes were correct, file an appeal demonstrating the diagnosis supports the procedure using medical records and physician documentation.

What should I do first when my health insurance claim is denied?

Read the denial letter to find the denial reason and appeal deadline. Call your insurer for clarification. Gather your medical records, EOB, and insurance policy. File a formal internal appeal before the deadline — typically 30 to 180 days. Missing the deadline permanently forfeits your appeal rights.

Do I need a lawyer to appeal a health insurance denial?

No. Most health insurance denials can be appealed successfully without a lawyer using a well-structured appeal letter, your medical records, and your doctor's support. Attorney-drafted templates give you professional legal framing without the cost of retaining a lawyer.

What are the most important tips for winning a health insurance appeal?

Always file before the deadline. Address the specific denial reason rather than writing a generic letter. Get a detailed medical necessity letter from your treating physician. Include all relevant medical records. Cite clinical guidelines supporting your treatment. Send via certified mail and keep copies of everything.

What is the biggest mistake people make when appealing an insurance denial?

Writing a generic appeal that does not directly address the insurer's stated reason for denial. Each denial type requires different legal and clinical arguments. Match your arguments to the denial code and reasoning in your denial letter.

Are insurance companies using AI to deny claims?

Yes. Many major health insurers now use automated AI systems to review and deny claims — often without meaningful human review. These automated denials are legally challengeable through the standard appeal process.

What are the most common reasons health insurance claims are denied?

The most common reasons are: lack of prior authorization, treatment deemed not medically necessary, out-of-network provider, policy exclusion, diagnosis and procedure code mismatch (CO-167), deductible not met (PR-1), and experimental or investigational treatment classification. Most are appealable.

What is the difference between an internal and external insurance appeal?

An internal appeal is reviewed by your insurance company and is the required first step. An external appeal is reviewed by an independent organization — and its decision is legally binding on the insurer. Under the ACA, most health plans must offer external review after an internal appeal denial.

Insurance Denied My Surgery or Hospital Stay: What to Do Next

May 25

Written By Tatiana Kadetskaya

A denial for surgery or hospitalization can feel like the floor dropping out. Here's what you need to know.

You needed surgery. Your doctor ordered it, scheduled it, and in many cases already performed it. And now your insurance company is saying it won't pay — or wasn't going to pay — because the procedure was "not medically necessary," required prior authorization that wasn't in place, or falls outside your coverage.

These denials are among the most financially devastating and emotionally distressing in health insurance. Bills for surgeries and hospitalizations routinely run into tens of thousands of dollars. They are also among the most commonly overturned on appeal.

This guide explains exactly why surgical and hospitalization claims get denied, what the law says about your rights, and how to build an appeal that works.

Why insurance companies deny surgery and hospitalization claims

"Not medically necessary"

This is the most common denial reason for surgical procedures. The insurer's internal criteria — not your surgeon's clinical judgment — determined that the procedure did not meet the threshold for medical necessity.

What this often means in practice: a billing code was submitted without enough clinical context to justify the procedure under the insurer's guidelines. Or the insurer's automated system flagged the diagnosis-procedure combination as not meeting its criteria. In many cases, a human clinician reviewed the denial for only minutes — or not at all.

The appeal argument here is clinical. You need to document why conservative treatment failed, what the risks of not having surgery are, and how the procedure meets your policy's definition of medical necessity. The cornerstone of this argument is a letter of medical necessity from your surgeon — a formal document that goes far beyond a surgical note.

Prior authorization was not obtained or was denied

Many surgeries require the insurer to pre-authorize the procedure before it is performed. If authorization was not requested, was denied, or was obtained for a related but different procedure, the claim may be denied after the fact.

If your surgeon's office failed to obtain authorization, this is a common scenario — and it is not necessarily your fault. Many states have laws that prohibit insurers from denying claims due to administrative failures by in-network providers. Your appeal can argue that the authorization failure was the provider's responsibility, not yours, and that you had a reasonable expectation of coverage.

If authorization was denied before surgery, and you proceeded with the procedure anyway because it was medically urgent or your physician recommended it, your appeal needs to address why the urgency or medical necessity justified proceeding without authorization.

The hospital stay was "longer than necessary"

Insurers often authorize a surgery but dispute the length of the hospital stay that follows. If the insurer determines — using its own criteria — that you were hospitalized for longer than medically necessary, it may deny payment for the additional days.

These denials are frequently wrong. Post-surgical complications, patient-specific risk factors, physician-directed observation requirements, and discharge planning challenges are all legitimate reasons for extended stays that insurers may not account for in their standard criteria.

Your appeal needs to document, day by day if necessary, why each day of hospitalization was clinically warranted — with physician notes and nursing records to support it.

The procedure was denied as experimental

Newer surgical techniques, robotic-assisted procedures, or surgeries used for emerging indications may be labeled "experimental or investigational" by insurers, even when they are widely performed and supported by clinical evidence.

The argument here is the same as any experimental treatment appeal: published clinical guidelines, FDA clearance, peer-reviewed surgical literature, and your physician's documentation that this is an accepted standard of care for your condition.

Out-of-network surgeon or facility

If your surgery involved an out-of-network surgeon or was performed at an out-of-network facility, your claim may be denied or paid at a sharply reduced rate. Emergency surgeries and cases where no in-network specialist was available are specifically protected under federal and state law, including the No Surprises Act.

What the law says about surgical and hospital denials

Federal law under the Affordable Care Act requires insurers to provide a full and fair review of every appeal. For surgical denials specifically:

If the surgery has not yet occurred, you can request an expedited appeal, which must be decided within 72 hours when a delay would seriously jeopardize your health.
If the surgery has already occurred, you have the right to a standard internal appeal, typically with a 30 to 60-day decision window.
If your internal appeal is denied, you have the right to an external review by an independent organization whose decision is binding on the insurer.

The external review process is particularly valuable for surgical denials because an independent clinical reviewer is not subject to the same financial incentives as the insurer's reviewers. Learn how external appeals work →

Check your appeal deadline before doing anything else. Missing it permanently forfeits your right to challenge the denial. Check deadlines by insurer →

How to build a surgical appeal that works

Step 1 — Get your surgeon to write a letter of medical necessity

This is not optional for surgical appeals. Your surgeon needs to write a letter that specifically addresses the insurer's denial reason, documents the failed conservative treatments, explains the clinical basis for surgery, and describes the consequences of not operating. A standard operative note is not enough. Here's exactly what that letter needs to include →

Step 2 — Gather your complete medical record relevant to the surgery

The insurer needs to see the clinical trail that led to surgery: prior treatment records, imaging, specialist consultations, failed conservative care, and the physician recommendations that preceded the surgical decision. Submit these as attachments referenced in your appeal letter.

Step 3 — Pull your policy's medical necessity definition

Your Summary Plan Description contains your plan's definition of medical necessity. Your appeal letter must quote it and demonstrate, element by element, how your surgery meets it. Generic appeals that don't engage with policy language are routinely denied.

Step 4 — Research and cite clinical guidelines

If a relevant medical society — the American College of Surgeons, your specialty's board, or a published clinical practice guideline — recommends this procedure for your diagnosis, cite it by name. This is particularly important if the insurer labeled the procedure "experimental" or used narrow internal criteria to deny it.

Step 5 — Write a structured appeal letter that ties it all together

Your appeal letter is not a narrative of what happened to you. It is a legal argument that connects the clinical evidence to your policy language and demands a specific outcome. The structure matters as much as the content. See how insurers actually review appeals →

The financial reality of letting a surgical denial stand

Surgery and hospitalization denials are not like denied office visits. The numbers involved are serious:

A typical inpatient surgery: $20,000 to $80,000
A multi-day hospitalization: $10,000 to $20,000 per day in some cases
Post-surgical complications requiring extended care: potentially hundreds of thousands

Our Medical Necessity Appeal Letter Template costs $29. It was written by a licensed insurance attorney specifically for denials like yours — built to present the clinical argument your insurer needs to see, in the format reviewers are trained to evaluate.

Don't accept a denial on a $30,000 surgery without filing a proper appeal.

Download the Medical Necessity Appeal Template — $29 →

Not sure this is the right template for your denial? Answer 3 questions and find out →

Frequently Asked Questions

Can I appeal a surgery denial after the procedure has already been done?

Yes. Post-service appeals — where the surgery has already occurred — are fully allowed. You are appealing for coverage of care that was already provided. The process and deadlines are the same as a pre-service appeal, though your arguments may shift slightly depending on whether prior authorization was an issue.

My surgeon's office said they got authorization. Why was my claim still denied?

Authorization and payment are not the same thing. An insurer can authorize a procedure for scheduling purposes but later deny the claim on the basis that the documentation submitted didn't support medical necessity. This is a common frustration and a common basis for appeal — the authorization creates a strong argument that the insurer approved the procedure.

The insurer says my hospital stay was "too long." Can I appeal that?

Yes. Extended stay denials are common and frequently overturned when the clinical record documents why each day was medically required. Your physician's daily notes, nursing records, and documentation of any complications or discharge planning delays are the key evidence.

What if my surgeon is out-of-network?

If the surgery was an emergency, or if no in-network surgeon with appropriate expertise was available, federal and state law — including the No Surprises Act — limits what insurers can charge you and may prohibit certain out-of-network denials. Reference the applicable statute in your appeal.

What are my chances of winning a surgical appeal?

Appeal success rates for medical necessity denials — which cover most surgical denials — run between 40% and 60% according to published data. The single biggest factor is the quality of the appeal: a structured, evidence-based letter with a strong physician letter of medical necessity wins far more often than an unstructured complaint.

Tatiana Kadetskaya