A denial letter has a particular weight to it. Your doctor said you need the treatment, and a company you pay every month said no. Most people read that letter, assume the decision is final, and absorb the cost or go without the care.
The decision is not final. A denial is the insurer’s opening position, and federal law gives you a formal process to challenge it. This guide walks through that process step by step, including the California review that most people have never heard of.
First, the numbers worth knowing
Why Most Health Insurance Denials Are Never Appealed
in-network claims were denied in KFF’s analysis of HealthCare.gov plans in 2023.
of those denials were ever appealed.
KFF analyzed claims data from HealthCare.gov plans and found insurers denied nearly 1 in 5 in-network claims in 2023. Fewer than 0.2% of those denials were ever appealed.
Sit with that second number. The overwhelming majority of denials are simply accepted. The appeal rights written into federal law go unused, which means the system’s math rewards the insurer every time a family gives up at the letter.
The appeal process
How to Appeal a Health Insurance Denial Step by Step
Use the denial reason, claim file, doctor support, written appeal, and external review path together.
Step 1: Read the Health Insurance Denial Letter
Every denial letter must state the reason for the denial and explain your appeal rights. Find the specific reason code or language: not medically necessary, experimental, out of network, or a missing prior authorization. Your appeal answers that exact reason, not denials in general.
Then find your deadline. For most ACA-governed plans you have at least 180 days from the denial notice to file an internal appeal. Medicare, Medicaid, and some self-funded employer plans run on different timelines, so confirm the date printed in your letter and put it on the calendar that day.
Step 2: Request Your Claim File Before You Appeal
Under federal regulations, you can request every document and record the insurer used to make its decision, at no charge. This is the discovery phase most people skip.
The claim file shows you what the reviewer actually looked at. Files are often thinner than families expect. If the reviewer never saw the imaging report or the failed-medication history, your appeal now has its argument.
Step 3: Get Doctor Support for the Insurance Appeal
You are not arguing medicine. Your treating doctor already made the case for the treatment, and the appeal’s job is to put that case in front of someone required to read it. Ask your doctor’s office for a letter of medical necessity that responds to the denial reason directly, and ask whether a peer-to-peer review is available.
The framing matters. The appeal forces the plan to justify overriding the judgment of the physicians who examined you. That is a harder position to defend in writing than it is in a form letter.
Step 4: Write the Internal Health Insurance Appeal
Keep it organized and specific. State what was denied, quote the denial reason, and answer it with documentation: the doctor’s letter, the relevant records, and anything missing from the claim file. Reference your plan’s own coverage language where it supports you. Send it by a trackable method, keep copies of everything, and log every call with a date and name.
If your health problem is urgent, ask for an expedited review. In California, DMHC-regulated plans must decide urgent appeals within 3 days.
For California families, a health insurance denial can involve more than one office, doctor letter, billing department, medical record, and appeal deadline. BellWell helps organize the denial reason, claim file, supporting records, provider communication, and California review options so families do not have to manage every step alone.
Step 5: Use California IMR After an Insurance Denial
This is the step most families never reach, and it is where the odds change.
If your internal appeal is upheld, most plans must offer an independent external review, and the insurer is legally required to follow the external reviewer’s decision.
California goes further. If a DMHC-regulated plan denies a service as not medically necessary, refuses to cover an experimental or investigational treatment, or will not pay for emergency or urgent care you already received, you can request an Independent Medical Review through the state’s Department of Managed Health Care.
Independent doctors with no tie to your health plan decide it, usually within 45 days, or about 7 days when your doctor documents that the problem is urgent.
It is binding. Per the DMHC, approximately 73% of enrollees who submit IMR requests receive the service or treatment they requested, based on the DMHC’s 2024 Annual Report. When the review goes your way, the plan must authorize the service within 5 business days.
You generally need to complete your plan’s grievance process first, or wait 30 days after filing it. Medicare enrollees, Medi-Cal fee-for-service members, and self-funded employer plans fall outside the IMR process and use different appeal paths.
What are the odds?
What Are the Odds of Winning a Health Insurance Appeal?
Honest answer: most denials are never appealed, so most denials stand. When denials are appealed, outcomes shift. In KFF’s analysis of HealthCare.gov plans, 44% of appealed denials saw at least partial reversal at the internal stage. In California, the DMHC reports approximately 73% of IMR cases end with the enrollee receiving the requested service.
Those numbers do not promise an outcome in your case. They do say the quiet part out loud: the families who push past the first no win often enough that the appeal is worth writing.
Most denials are never appealed. The families who push past the first no win often enough that the appeal is worth writing.
FAQs About How to Appeal a Health Insurance Denial
Internal appeals run on your plan’s clock, with expedited review required for urgent cases. A California IMR is usually decided within 45 days of qualification, or about 7 days when expedited.
No. The internal appeal, your claim file, and the California IMR are all free to you.
Yes. California’s IMR process allows a designated person to assist you through the DMHC’s Authorized Assistant Form. The appeal stays in your name. The legwork does not have to stay on your desk.
Different rails. Medicare has its own appeals process with five levels, and self-funded employer plans follow federal ERISA rules rather than California’s IMR. The principles in this guide still hold: read the letter, get the file, anchor on your doctor’s reasoning, meet the deadline.
When to Get Help With a Health Insurance Denial Appeal
Plenty of families handle a first appeal on their own with the steps above. Where it gets heavy is the second denial, the urgent case running against a discharge clock, or the appeal that needs records pulled from four providers while you are working and caregiving at the same time.
That coordination is the work we do. If a denial is sitting on your desk, here is our booking page below. We are happy to take this on for you, whether that is organizing the appeal file, coordinating with the doctor’s office on the medical necessity letter, or managing the IMR submission and follow-through. We are here to help whether it is month to month support or a one off engagement.
Schedule a free 30-minute call