how to

Appeal a Denied Insurance Claim Step by Step

· 2 min read insurance-claimsappealshealth-insurancepaperwork

A denial letter is a position statement, not a verdict. Insurers deny claims for coding errors, missing prior authorization, and documentation gaps that a single well-aimed letter often fixes. Persistence pays because most internal appeals that include new evidence succeed.

What you need

  • The denial letter with its specific denial reason code
  • Your policy or plan document
  • All medical records, bills, and explanation of benefits related to the claim
  • Notes on every phone call: date, representative name, reference number

Step by step

  1. Decode the denial. Find the exact reason on the letter or EOB, such as CO-29 (late filing) or "not medically necessary." You cannot fight what you have not identified.
  2. Compare the stated reason against your plan documents. Many denials cite a policy exclusion that does not actually match the service billed.
  3. Call the insurer and ask whether it was a coding error. Billing codes get transposed constantly; this call alone resolves a large share of denials within days.
  4. Request the denial file if the reason is medical necessity. Federal rules entitle you to the criteria used, usually MCG or InterQual guidelines.
  5. Write the appeal letter around one argument: why the care meets the plan's own coverage criteria or why the coding is wrong. Attach records, not opinions.
  6. Send by certified mail or the payer's portal, before the deadline, typically 180 days from denial. Keep copies of everything.
  7. Escalate if the internal appeal fails: request external review by an independent reviewer. For health plans, this decision binds the insurer.
  8. For property claims, bring in a public adjuster only when the gap between offer and actual loss is large enough to justify their percentage fee.

Common mistakes

  • Arguing hardship or emotion instead of citing policy language and clinical criteria
  • Missing the appeal deadline while gathering more evidence; file first, supplement later
  • Accepting "the doctor's office will handle it" without confirming an appeal was ever filed

Related guides

Strong documentation habits start earlier: see [[home-inventory-document-claims]] for property proof and [[compare-health-plan-tiers]] for knowing what your plan promised in the first place. If repeated disputes suggest your limits are wrong, revisit [[life-insurance-needs-calculation]].

← All guides