The denial letter is designed to feel final. It isn't. Insurers reverse a meaningful share of denials when patients push back with documentation — but most people never appeal at all. The system quietly counts on that.

You're allowed to be angry about this. Then let's turn the anger into a paper trail.

Step 1: Decode the denial letter

Somewhere in the letter is the actual reason, usually one of these:

  • "Not medically necessary" — the insurer's reviewer disagrees with your doctor. This is the most common and most winnable category.
  • Administrative — a coding error, missing prior authorization, or paperwork mismatch. Often fixable with a corrected claim, not a full appeal.
  • "Not covered" — the plan says it excludes this. Sometimes true; sometimes the plan documents say otherwise.

Find three things and write them down: the stated reason, the appeal deadline, and the appeal address or portal. Deadlines are typically around 180 days for internal appeals — generous, but they arrive faster than you'd think when you're unwell.

Step 2: Build the record

Appeals are won on paper. Gather:

  • the denial letter and the relevant Explanation of Benefits;
  • your plan's coverage documents (the section on your service — ask HR or the insurer for the full plan document if you have a summary only);
  • a letter of medical necessity from your doctor — ask for it directly; offices write these routinely;
  • supporting records: the notes, tests, and failed prior treatments that make the case that this service is necessary for you specifically.

If the denial says "experimental" or "not medically necessary," ask your doctor whether published guidelines or peer-reviewed evidence support the treatment — citing them turns an opinion fight into an evidence fight.

Step 3: The internal appeal

Write a cover letter that stays factual: what was denied, why the reason is wrong, what the evidence shows, what you're asking for. Attach everything. Send it trackably — portal with screenshots, or certified mail.

Then log every contact: date, name, what was said. If it isn't written down, it didn't happen.

If care is urgent, say so explicitly and ask for an expedited appeal — plans must decide those in days, not weeks.

Step 4: External review

If the internal appeal fails, you generally have the right to an independent external review — a decision by reviewers outside your insurance company, and one the insurer must abide by. The final denial letter has to tell you how to request it. Employer self-funded plans follow a federal process; other plans go through your state. Either way: this stage exists because internal appeals aren't the last word.

The whole picture

An appeal is a project — deadlines, documents, follow-up calls — dropped on you at exactly the moment you have the least capacity for projects. That's not a reason to skip it; it's a reason not to carry it alone. Billing and appeal support is one of the four things I do for clients, start to finish. And whatever you decide: don't let the deadline pass quietly. The letter is betting you will.