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Your guide to timely filing appeal letters (with examples)

Wondering how to write one? Here’s what you need to know.

May 22, 2025

6 min read

If you’re a therapist who accepts insurance, there will inevitably come a time when one of your claims is denied. Denials can happen for all sorts of reasons — but a common one involves failure to meet timely filing requirements.

Insurers establish timely filing windows to dictate how much time providers have to submit claims related to provided services. These standards vary quite a bit by insurance provider; some may give clinicians just 30 days from the date of service, while others may still accept claims a full year later.

Headway handles claim submission on behalf of its providers, so they don’t have to worry about keeping track of and meeting timely filing requirements. But for providers without that benefit, denials related to timely filing are likely to crop up from time to time. Luckily, however, these denials can often be appealed. Here’s how.

What is a timely filing appeal letter?

A timely filing appeal letter challenges a denial related to alleged failure to meet timely filing requirements. If a claim was indeed submitted late, the insurer’s denial will be difficult to reverse unless there were uncontrollable extenuating circumstances at play. 

If a denial was made wrongfully, however, an appeal may rectify the situation. For example, a clinician would have strong grounds for an appeal if they have proof that their claim actually was submitted on time, but was not processed properly due to errors made by their claims clearinghouse or the insurance company itself. 

What is a corrected claim?

Although they are similar, appeals and claims corrections are different processes. A corrected claim revises or replaces a previously submitted claim, often to add new information or correct mistakes on the first claim. An appeal, by contrast, challenges a decision made by an insurance carrier.

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What to include in a timely filing appeal letter

When submitting a timely filing appeal letter, your goal is to make an airtight case that your claim was, in fact, submitted within the proper timeline. To do so, you’ll need to provide information about the session that took place and proof that you followed proper procedures when submitting your claim related to it. Every timely filing appeal letter should include:


  • The patient’s name and healthcare ID number
  • The date of service
  • The original claim number
  • Total amount billed on that claim
  • Proof of timely filing (such as confirmation of electronic submission or a confirmation from a claims clearinghouse)
  • The insurer’s denial letter
  • A copy of the original claim

How to obtain proof of timely filing

The most important thing to include with your appeal letter is proof that the original claim was, in fact, submitted on time. There are several ways you can secure that evidence, including:


  1. If you submit claims using a platform — like Headway — with EHR functionalities, you can simply ask the platform’s support team for proof of timely filing.
  2. If your claim was processed through a claims clearinghouse, you can contact the clearinghouse’s support team for assistance.
  3. If you have digital proof that the claim was submitted and accepted on time — such as acknowledgment from the payer or a submission confirmation report from the payer or clearinghouse — that can also serve as proof.

Timely filing appeal letter example

From time to time, you may receive denial notices related to claims you know were submitted promptly and correctly — with the documentation to prove it. In these situations, it’s appropriate to appeal the payer’s decision, using an appeal letter like the one outlined below.

[Your Name, Credentials]

[Your Practice Name]

[Address]

[City, State, ZIP Code]

[Phone Number]

[Email Address]

[Date]


Re: Timely Filing Appeal for Denied Claim

Patient Name: [Patient Full Name]

Patient ID/Policy Number: [Insurance ID Number]

Date of Service: [MM/DD/YYYY]

Claim Number: [Claim Number, if available]


To Whom It May Concern,

I am writing to formally appeal the denial of the above-referenced claim, which was rejected due to an alleged failure to meet the timely filing deadline. As a licensed [Your Profession, e.g., Licensed Clinical Social Worker], I take filing compliance seriously, and I respectfully request a reconsideration of this claim based on the evidence of timely submission and an apparent internal error within your system.

The claim for services rendered on [Date of Service] was submitted electronically on [Original Submission Date], which was well within your timely filing requirement of [insert time frame, e.g., 90 days from the date of service]. Attached, you will find the electronic submission report [or clearinghouse confirmation] that clearly shows the claim was submitted on [date]. Additionally, no rejection or request for correction was received at the time, leading us to believe the claim was in process.

It appears this denial may have been the result of a processing error on your end. As providers, we rely on accurate and timely communication from payers to ensure compliance and continuity of care. I am requesting that this claim be reprocessed and paid accordingly, as we have provided sufficient proof of timely submission.


Attached Documents:

  • Electronic claim submission confirmation
  • Clearinghouse transmission report (if applicable)
  • Copy of the original claim
  • Denial notice


Please let me know if any further documentation is required. I appreciate your prompt attention to this matter and look forward to a resolution.

Sincerely,

[Your Full Name, Credentials]

[Your NPI Number]

[Your Practice Name]

What happens if a timely filing appeal is denied?

A timely filing appeal may be denied if you do not supply adequate proof that you submitted the original claim within its required timeframe. Ironically, appeals can also be rejected if they are not filed within a timeframe set by the payer.

If an appeal is denied, it’s not necessarily the end of the road. Reconsideration requests are considered “second-level” appeals. As the name suggests, a reconsideration request asks an insurance company to revisit its initial decision on an appeal. Providers may progress to this step if they have new proof to back up their argument, if they believe evidence was overlooked during the initial appeal process, or if they have a compelling argument as to extenuating circumstances that caused them to miss the initial deadline.

Headway takes care of claims for you

Headway providers don’t have to worry about denials, appeals, and other insurance headaches, because Headway’s free, comprehensive platform includes assistance with claim submission. We take care of the claims for you — so you can take care of your clients.

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This content is for general informational and educational purposes only and does not constitute clinical, legal, financial, or professional advice. All decisions should be made at the discretion of the individual or organization, in consultation with qualified clinical, legal, or other appropriate professionals.

© 2026 Therapymatch, Inc. dba Headway. All rights reserved. No part of this publication may be reproduced without permission.

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