When your health plan denies a claim, your first formal step is an internal appeal — asking the insurer to review its own decision. For most plans subject to the Affordable Care Act, you generally have 180 days from the date of the denial notice to file, and the plan must give you its decision within set timeframes. Always confirm the exact deadline and address on your denial letter / EOB, because plans differ (and Medicare, Medicaid, and some self-funded plans use their own process).
Before you write
Find the denial reason and code on the EOB or denial letter, and gather support: your doctor’s notes, the order for the service, relevant medical records, and — if the denial is about medical necessity — a letter of medical necessity from your provider (see that separate letter).
The letter
[Your full name]
[Your address]
[City, State ZIP]
[Phone] | [Email]
[Date]
[Insurance company - Appeals Department]
[Address from your denial letter]
Re: Internal appeal of denied claim
Member: [Name] Member ID: [number] Group #: [number]
Claim number: [number] Date(s) of service: [dates]
Denial date: [date] Denial reason/code: [as stated on the EOB]
To the Appeals Department:
I am requesting a full internal appeal of the denial of the claim above. I
believe this service is covered under my plan and that the claim should be paid.
Reason this denial should be reversed:
[State your case plainly. Examples:
- The service was medically necessary; see the attached letter from my
physician and the supporting records.
- The service is a covered benefit under my plan documents (see section [x]).
- The denial was a coding/processing error: [explain].
- Prior authorization was obtained on [date], reference [number].]
Enclosed in support:
- [Letter of medical necessity from Dr. [name]]
- [Relevant medical records / test results]
- [Copy of the EOB / denial letter]
- [Plan document page showing the benefit, if applicable]
Please review this appeal and notify me of your decision in writing within the
timeframe required for my plan. If the denial is upheld, please send the specific
reason and tell me how to request an external review.
Thank you,
[Your signature]
[Your printed name]
How to send it
File within your plan’s deadline (often 180 days for ACA plans — check the letter). Send by certified mail with return receipt, or through the insurer’s official appeals channel if it generates a confirmation. Keep a dated copy of everything. For a time-sensitive treatment, ask for an expedited (urgent) appeal.
Notes. Standard internal-appeal decisions are typically due within about 30 days for services not yet received and 60 days for services already received, and 72 hours for urgent care — but exact timeframes are set by your plan and plan type, so rely on your denial letter. If the internal appeal fails, you can usually escalate to an external review. This is general information, not legal or medical advice.