Information checked: September 9, 2026.
A strong health insurance appeal letter identifies the disputed claim, states why the denial is wrong, and supplies the clinical and plan evidence needed to reverse it. It should follow the address and deadline printed on the denial notice.
Key answer: Include the patient's name, address, member ID, claim or authorization number, service and provider, denial date and reason, a clear statement that you are appealing, the requested outcome, and supporting records. For many ACA-covered health claims, request internal appeal within 180 days of the denial.
Table of contents
- Information to include
- Evidence to attach
- Where to send it
- Urgent appeals
- After submission
- Frequently asked questions
Information to include
- Patient and policyholder names
- Address, phone, member ID, and group number
- Claim, reference, or prior-authorization number
- Service date, provider, diagnosis or procedure when relevant
- Exact denial reason and policy provision
- Why the service is covered or medically necessary
- The specific decision requested
Put “Appeal of denied claim” and the claim number in the subject line. If representing someone else, include the insurer's authorization form.
Evidence to attach
Attach the denial notice and Explanation of Benefits, relevant plan language, medical records, treatment history, and a clinician letter explaining medical necessity and why alternatives are inappropriate. Label attachments and cite them in the letter. Send copies, not irreplaceable originals.
Where to send it
Use the mailing address, fax, portal, or other method on the denial. A Marketplace eligibility appeal is different from an insurer claim appeal and goes to the Marketplace Appeals Center under its own 90-day rule. Do not send a plan claim to the Marketplace merely because the plan was purchased there.
Keep a full copy and proof of delivery. If faxing, retain the transmission report; if uploading, save the confirmation screen.
Urgent appeals
If delay could seriously risk life, health, or the ability to regain maximum function, request expedited review and explain the medical urgency. CMS says internal urgent-care appeals are decided within 72 hours, and qualifying expedited external review must be completed as quickly as the condition requires and no later than 72 hours after receipt.
After submission
Record the received date and expected decision date. CMS lists up to 30 days for a non-urgent service not yet received and 60 days for a service already received under applicable rules. If the internal appeal remains denied, read the external-review instructions immediately.
Frequently asked questions
Do I need a special form?
Use the insurer's form if required. CMS also recognizes a written request containing the necessary information for applicable plans.
Should my doctor write a letter?
A clinician letter can be important for medical-necessity or prior-authorization denials.
Can I send more evidence later?
Only if the plan permits it. Submit the strongest complete packet before the deadline.
Final checklist
Follow the denial notice, identify the claim precisely, connect the plan rule to medical evidence, request the remedy, and retain proof of timely submission.
Related guides
- Insurance Claim Denied: Appeal Deadlines, Required Documents, and Next Steps
- Itemized Medical Bill Request: How to Find Errors Before You Pay