Quick answer
Read the denial letter to find the reason and the deadline, then file a written internal appeal with your insurer, usually within 180 days. Include a letter from your doctor explaining why the care is medically necessary and any records that support it. If the insurer still says no, you can ask for an external review by an independent reviewer, whose decision the insurer must follow.
Key takeaways
- Many denials are paperwork problems a phone call or corrected claim can fix.
- You generally have at least 180 days to file an internal appeal.
- Urgent cases get fast decisions: 72 hours for urgent internal appeals and expedited external reviews.
- You have 4 months after a final internal denial to ask for an external review.
- Few people appeal. KFF found fewer than 1% of denied marketplace claims were appealed in 2024.
On this page
Why claims get denied
HealthCare.gov insurers denied 19% of in-network claims in 2024, according to KFF, and rates ranged from 3% to 36% depending on the insurer. Common reasons include:
- Paperwork problems, like a wrong code, a missing referral or a typo in your member ID.
- No prior approval for a service that needed it, which often happens with surgery and imaging.
- Not medically necessary, in the insurer’s view.
- Not covered by your plan.
- Out of network.
Step 1: Read the denial and your plan
Your denial letter or explanation of benefits must give the reason and explain how to appeal. Find:
- The exact reason and any codes.
- The deadline to appeal.
- The plan rule or medical criteria the insurer used. You can ask for copies of the documents behind the decision at no charge.
Then check your plan’s coverage documents to see whether the service should be covered.
Step 2: Call the insurer and your doctor
If it looks like a billing mistake, ask your doctor’s office to fix and resubmit the claim. For prior authorization and medical necessity denials, your doctor can often request a “peer-to-peer” call with the insurer’s medical reviewer. Write down who you talked to and when. See what is prior authorization.
Step 3: File an internal appeal
- File in writing, using the insurer’s form if it has one, and include your claim number.
- Include a letter of medical necessity from your doctor, medical records, and any studies or guidelines that support the treatment.
- Explain in plain words why the denial is wrong, pointing to your plan’s own language when you can.
- Keep copies of everything and send it in a way you can track.
You can appeal for a family member on your plan, such as a child. See covering all family members under the same policy.
| Type of appeal | Plan’s deadline to decide |
|---|---|
| Urgent care | 72 hours |
| Care you haven’t gotten yet | 30 days |
| Care you’ve already received | 60 days |
Step 4: Ask for an external review
If the insurer upholds its denial, you can ask for an external review by an independent organization. You have 4 months after the final denial to request it. Standard reviews are decided within 45 days, and expedited reviews within 72 hours. The insurer must accept the reviewer’s decision. For urgent situations, you can ask for an expedited external review at the same time as your internal appeal.
Step 5: Get help if you need it
- Your state’s insurance department or consumer assistance program can help with individual and many job-based plans.
- For job-based plans, the U.S. Department of Labor’s benefits advisors can help at askebsa.dol.gov or 1-866-444-3272.
- Your employer’s HR or benefits office can sometimes push a claim along.
- For large bills, a patient advocate or attorney may be worth it.
Ask the provider to put the bill on hold while your appeal is pending, so it doesn’t go to collections.
If you lose the appeal
Ask the provider for a discount, financial assistance or a payment plan. What if you can afford your medical bills out of pocket covers paying your own way. Insurers differ in how they handle claims as well as in what they charge, so if you keep running into denials, look at the best health insurance companies and how to switch health insurance companies at the next open enrollment.
Ready to compare insurers? See plans and prices by ZIP code.
Frequently asked questions
How long do I have to appeal a health insurance denial?
Usually at least 180 days from the denial notice for an internal appeal, and 4 months after a final internal denial for an external review. Check your denial letter for your plan’s deadlines.
Do health insurance appeals work?
Often enough to be worth trying. Insurers reversed about a third of the marketplace denials that were appealed in 2024, according to KFF, and external reviewers overturn some of the rest.
Can my doctor appeal for me?
Yes. Your doctor can file on your behalf, and a letter from your doctor is often the strongest part of an appeal.
What if I need the care urgently?
Ask for an urgent (expedited) appeal. The insurer must decide within 72 hours, and you can request an expedited external review at the same time.
Sources
This article is general information, not legal or insurance advice. Appeal rules and deadlines depend on your plan and state. Last reviewed September 2026.