What a denial letter must tell you

Federal rules set out what a denial notice must say. The list is longer for an employer plan or insurance company that is not “grandfathered” (in place on 23 March 2010 and not changed in ways that end that status). This page gives the list as the rule states it, so you can lay your letter beside it and see what is missing.

What this means

The rules here apply to private coverage: job-based plans and plans you buy yourself, including Marketplace plans. They do not apply to Medicare, Medicaid, TRICARE or Veterans Affairs coverage, which have their own notice rules, or, under the Affordable Care Act, to short-term plans, health care sharing ministries and fixed indemnity products. We have not confirmed whether the general federal claims rule for employer plans covers a fixed indemnity plan that comes through an employer. A denial in this sense includes a refusal, a cut, an ending, or a failure to pay in whole or in part. It also covers a finding that care is experimental, investigational or not medically necessary.

Every denial from a private group plan under the Employee Retirement Income Security Act (ERISA)

ERISA is the federal law that covers most job-based plans. The notice must be written or electronic, “calculated to be understood by the claimant”, and must state:

• the specific reason or reasons for the denial
• the specific plan provisions the denial relied on
• any additional material needed to fix (“perfect”) the claim, and why it is needed
• the plan’s review procedures and time limits, including your right to sue under ERISA section 502(a) after a denial on review

It must also say, if the plan used an internal rule, guideline or protocol, either what it says or that it was relied on and a free copy is available on request. If the denial rests on medical necessity, experimental treatment or a similar limit, the notice must either explain the scientific or clinical judgment, applying the plan’s terms to your medical circumstances, or say that the explanation is free on request.

Extra items from plans and insurers that are not grandfathered

• enough information to identify the claim: the date of service, the provider and the claim amount, if applicable
• a statement that the diagnosis code and treatment code, and what they mean, are available on request
• the denial code and its meaning
• a description of the standard used to deny the claim
• how to start an internal appeal and external review (review by an independent reviewer outside the plan)
• contact details for any state consumer assistance program or ombudsman

A final internal denial from these plans must also include “a discussion of the decision”, not just a code.

Special cases

• Urgent care. The denial may come by phone first, but a written notice must follow within 3 days and must describe the fast review process.
• After an appeal. A denial on appeal must also say you may receive, free on request, copies of all documents relevant to the claim; describe any voluntary appeal levels; and state your right to sue under ERISA section 502(a).
• Mental health and substance use disorder benefits. The reason for any denial must be made available to you on request.
• Language. If 10 percent or more of the people in your county can read only the same non-English language, the plan must offer oral help in that language, give the notice in that language on request, and put a statement on the English notice explaining how to get language services.

What to do

1. Put the letter beside the list. The denial letter contents checklist and the denial letter checker do this for you.
2. Mark each missing item. Note it with the date you received the letter.
3. Ask in writing for what is missing. Use the claim file request and the request for clinical criteria. Say what you are asking for and ask for a reply in writing.
4. Keep your appeal on track. A request for the diagnosis and treatment codes cannot be treated by the plan as filing an appeal. Find your deadline, and file by it whether or not the missing pieces have arrived (check the date on your notice, which controls).
5. Keep a copy of everything, including how and when you sent each request.

What the plan may say, and what to say back

“The explanation is available on request.” That is allowed for the clinical explanation and the internal rule. Make the request, in writing, and keep a copy.

“Your claim was denied under code [number].” Ask what the code means and which plan provision applies. Non-grandfathered plans must give the denial code and its meaning.

The rule

A group health plan’s denial notice must give the specific reasons and plan provisions relied on, the material needed to perfect the claim, and the review procedures and time limits. Non-grandfathered plans and insurers must add claim details, the denial code, the standard used, and how to start internal appeals and external review. Source: Code of Federal Regulations (CFR) Title 29, section 2560.503-1(g) and 29 CFR 2590.715-2719(b)(2)(ii)(E).

Watch for

• Grandfathered plans. They skip the extra items above, but a grandfathered employer plan under ERISA must still follow the ERISA claims regulation, including the notice contents, the 180-day minimum to appeal and the document rights.
• A defective process has consequences, with limits. If a non-grandfathered plan or insurer does not “strictly adhere” to the internal appeal rules, you may go straight to external review or court. A minor violation that caused no harm, had good cause, happened during a good-faith exchange of information and is not part of a pattern does not count. You can demand a written explanation of any violation, which the plan must give within 10 days. For legal advice on this, contact a lawyer or the Department of Labor help line.
• Electronic delivery may change. On 23 July 2026 the Department of Labor proposed letting group health plans deliver denial notices by “notice and access” (an online posting with a right to ask for paper). Comments closed 21 September 2026. As of 11 November 2026, it is a proposal, not a final rule.
• Other programs. Medicare, Medicaid and other public programs have separate notice contents. See your rights when a plan says no.

What next

• Read a real letter step by step in how to read a denial letter line by line.
• Get the file the plan used: how to request your claim file.
• Check which kind of plan you have: how to find out what kind of plan you have.
• If the plan goes quiet, see when the plan is silent.