Why claims get denied
Marketplace-wide, claims year 2024. Note CMS does not link denial reasons to claim totals, so shares are of reported reason counts.
Frequently asked
What is the most common reason claims are denied?
The chart above shows the full CMS breakdown. Administrative issues such as missing prior authorization and billing-code problems lead; medical necessity and out-of-network care are the big coverage reasons.
Can a denied claim be resubmitted instead of appealed?
Often yes. Clerical denials, like a wrong billing code or a missing referral, are usually fixed by resubmitting corrected paperwork. Denials about medical necessity or coverage are worth a formal appeal.
What is a prior authorization denial?
Your plan required approval before the service and it was not given or was refused. Plans denied 12 to 18% of standard prior-authorization requests in 2025 according to KFF.
How do I fight a medical necessity denial?
Get your doctor's records showing why the care was needed and file an internal appeal. The appeal letter generator on this site formats the letter for you.