How to read an insurance denial letter
The letter looks like a verdict, but it is really a map. It hands you the reason, the deadline, and the next door to knock on.
CheckMyDenial team, patient billing and appeals. Published October 2026. Last reviewed 2026-10-29.
What does a denial letter have to tell me?
You are not alone, and the letter owes you more than a flat no. Under federal consumer rules for health plans, your insurer must tell you in writing that the claim was denied and explain why. It must also explain your right to appeal.
Insurers must also print the name of any Consumer Assistance Program in your state on denial notices. That is a program that can help you with an appeal. If any of these pieces is missing from your letter, that is worth noting.
These rules depend on your plan type. CMS says a plan that already existed on March 23, 2010 may be a grandfathered plan that does not have to follow them. Medicare, Medicaid, and dental-only plans can have their own steps, so the letter itself is your best guide.
Where is the reason for the denial in my letter?
Look for words like "reason for denial," "explanation," "why we made this decision," or a short code with a description next to it. The reason is usually near the top or beside the line for the service that was denied.
If you only see a code and no plain explanation, circle it anyway. You can ask your insurer in writing to explain the code and the exact reason.
How long do I have to appeal a denied claim?
For health plans covered by the federal rules, HealthCare.gov says you must file an internal appeal within 180 days (6 months) of receiving the notice that your claim was denied. Medicare, Medicaid, grandfathered, and dental-only plans can use different deadlines, so find the deadline printed on your letter and circle it first.
If your letter and a website disagree, go with the date on your letter and call the number on it to confirm. This is general information, not legal advice.
What do I do first when I get a denial letter?
Take a breath. Then work through it in order.
The steps below keep it simple.
- Step 1: Find the deadline. Circle the date by which you must appeal. Put it on your calendar with a reminder well before it.
- Step 2: Circle the reason. Mark the stated reason and any code. This is what an appeal has to answer.
- Step 3: Note the claim details. Write down the claim number, date of service, and your member ID. You will need them on every call and letter.
- Step 4: Get a second pair of eyes. Text a photo of the letter to (213) 606-6303 and we will read it and reply with where it breaks. It is free, with no account and no form.
What happens if my internal appeal is denied?
You may be able to ask for an independent external review. HealthCare.gov says the insurer's final determination must tell you how to request one, and that you must file a written request within 4 months after you receive that notice. CMS notes that some employer plans may ask you to go through two internal appeals first.
HealthCare.gov also says your insurer is required by law to accept the external reviewer's decision. Fees depend on the process: no charge in the HHS-administered process, and no more than $25 per review in others.
How fast must my insurer answer an appeal?
For health plans covered by the federal rules, HealthCare.gov says an internal appeal must be completed within 30 days for a service you have not received yet, and within 60 days for a service you already received. If the case is urgent, the insurer must speed up the process.
Keep copies of everything and write down the date and name for each call. If you have a Medicare health plan, Medicare.gov says the plan must tell you in writing how to appeal, and your local SHIP (find it at shiphelp.org) offers free health insurance counseling for people with Medicare.
Your checklist
- Circle the appeal deadline date
- Circle the stated reason and any code
- Write the claim number, date of service, and member ID
- Find the phone number and address for appeals
- Look for the state Consumer Assistance Program name
- Keep a copy of the letter and note every call
- Text a photo of the letter to (213) 606-6303
Which rules apply to you?
The steps and deadlines on this page can differ by the kind of plan you have. Your own denial letter always comes first.
- Coverage through a job:ask your HR team whether the plan is “self-funded” or “fully insured.” It can change who you can ask for help. Most private-sector job plans fall under a federal law called ERISA, and the U.S. Department of Labor’s EBSA takes health plan questions at Ask EBSA or 1-866-444-3272.
- Marketplace plan: follow the appeal steps at HealthCare.gov.
- Medicare or Medicaid: each has its own appeal process, listed on your notice.
- Dental-only plan: your plan contract sets the appeal rights, so read it and your letter.
Related answers
Sources: HealthCare.gov: Internal appeals. HealthCare.gov: External review. HealthCare.gov: Appealing a health plan decision. CMS: You have a right to appeal a denied claim. Medicare.gov: Filing an appeal. More in the full appeal guide.
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Free tools for the next step
Keep your appeal papers in one place. Take a photo of your denial letter, EOBs and insurance cards with GetPreCare, so they are on your phone when the insurer or the office asks. Free. Open GetPreCare. Helping a parent or partner? Set it up for them.