Winning a health insurance appeal: denials are a first offer

A claim denial arrives looking like a verdict. It's actually an opening bid. Federal data on ACA marketplace plans shows insurers deny roughly one in five in-network claims, patients appeal well under 1% of the time — and when patients do appeal, a large fraction of denials get overturned. That combination means the appeals process is one of the highest-expected-value pieces of paperwork in your financial life: the insurer is counting on you not filing it.

Why claims actually get denied

Most denials aren't a doctor at the insurer reviewing your case and disagreeing. They're automated: a missing prior authorization, a coding mismatch between what the provider billed and what the plan covers, 'not medically necessary' generated by an algorithm comparing your claim against plan criteria, out-of-network processing errors, or a missing referral. Because so many denials are clerical, a meaningful share can be fixed with a phone call asking the provider to rebill with corrected codes — before you ever write a formal appeal.

The two-level machine

Nearly every private plan gives you two rounds. First, an internal appeal: the insurer re-reviews its own decision, and you typically have 180 days from the denial to file. Second — and this is the part most people never learn — if the internal appeal fails, you're entitled to an external review by an independent third-party organization whose decision is binding on the insurer. External reviewers side with patients roughly 40% of the time. Urgent cases get expedited timelines (72 hours) at both levels. The denial letter is legally required to explain the reason, cite the plan provision, and spell out your appeal rights and deadlines — read it like a map, not a rejection.

1. 1
   Call and diagnose (day 1)

   Ask the insurer: exactly why was this denied, what code was billed, and what would make it payable? Log the date, time, and rep name. If it's a coding or prior-auth technicality, ask the provider's billing office to correct and resubmit.

2. 2
   Gather the record

   Request the claim file and the specific medical policy the denial relied on (you're entitled to both). Get your medical records for the service and the denial letter's exact language.

3. 3
   Recruit your doctor

   Ask your physician for a letter of medical necessity that addresses the insurer's stated criteria point by point, citing clinical guidelines. Provider offices do this constantly — ask for it explicitly.

4. 4
   File the internal appeal in writing

   One or two pages: what was denied, why the denial is wrong under the plan's own policy language, what the medical evidence shows, and what you're asking for. Attach the doctor's letter and records. Send it trackable, keep copies.

5. 5
   Escalate to external review

   If upheld, file for external review within the stated window (usually 4 months). It's free or nearly free, independent, and binding. Your state insurance department or Consumer Assistance Program can help — and for employer self-funded plans, the federal external review process applies.

Appeals that need extra muscle

• Prior-authorization denials for expensive drugs: ask your doctor about a peer-to-peer review — a direct call between your physician and the insurer's medical director often reverses these in one conversation.
• 'Experimental/investigational' denials: these are external review's sweet spot; independent physicians apply current evidence, not the plan's dated policy.
• Emergency care processed as out-of-network: cite the No Surprises Act and the prudent layperson standard — emergencies must be covered at in-network cost-sharing.
• Employer self-funded plans: your state insurance department can't regulate them, but federal external review still applies, and HR can pressure the administrator — the employer is the one actually paying claims.
• Denials stacking up on one condition: ask your state's Consumer Assistance Program or a nonprofit patient advocate for free help; hospitals' financial counselors also file appeals for care they delivered.

The bottom line

Denials are engineered friction, and the appeals process is the legally mandated path through it — internal review, then binding external review, with deadlines that favor you if you move. Diagnose the denial by phone, fix clerical issues at the source, arm your doctor's letter with the plan's own policy language, and escalate on schedule. The insurer's business model assumes you'll absorb the 'no.' Filing the appeal is how you decline.

The anatomy of a winning appeal letter

Since the letter is the whole product, here is its skeleton. Paragraph one: identify the claim (member ID, claim number, date of service, provider) and state plainly that you are appealing the denial dated X. Paragraph two: quote the denial's stated reason verbatim, then quote the plan's own coverage language or medical policy that contradicts it — this juxtaposition does most of the work, because internal reviewers are graded on whether decisions match policy, not on saving money per se. Paragraph three: summarize the clinical facts with dates, citing the attached records and the physician's letter. Paragraph four: state the specific remedy — process the claim at in-network benefits, authorize the medication, pay the allowed amount. Attach exhibits, number the pages, send it trackable. No rhetoric, no hardship narrative unless the plan's criteria make hardship relevant; the reviewer needs grounds to overturn, and your letter's job is to hand them those grounds in the fewest possible words.

Keep the meta-lesson too: every denial letter, EOB, and appeal you file builds a personal playbook that makes the next one faster. Households that treat insurance correspondence as a filing system rather than incoming fire — one folder per year, one template letter, a habit of calling for the real reason before writing — turn what feels like a bureaucratic ambush into routine maintenance with a 40–60% payout rate. Few systems in your financial life pay this reliably for this little skill. The insurer knows the odds; now so do you.