What is a timely filing limit?

To show proof of timely filing for a denied medical claim, you must provide system-generated, tamper-proof electronic or paper documentation establishing that the original claim was transmitted within the payer's required deadline.

Electronic Submissions

• Clearinghouse Reports: Pull an electronic batch report, transmission confirmation, or EDI acceptance report (such as a 277CA claim acknowledgment) from your billing software or clearinghouse showing the original submission and acceptance date.
• Reference Numbers: Locate the internal claim ID, clearinghouse reference number, or trace number assigned during the initial transmission.
• Vendor Support: If needed, request an official claim report or a signed timely filing verification letter from your platform provider (such as Office Ally or SimplePractice).

Paper Submissions

• Delivery Receipts: Provide official certified mail return receipts, USPS delivery confirmation, or courier tracking showing the package arrived before the deadline.
• Submission Logs: Include a copy of your internal, system-generated claim submission log matching the mailed date.

Submitting the Appeal

1. Draft an Appeal Letter: Include the patient's name, insurance ID, date of service, original claim number, and billed amount.
2. Attach Documentation: Include the denial notice (Explanation of Benefits showing code CO-29/CARC 29), a copy of the original claim, and your concrete proof of timely transmission.
3. Submit: Send the package via the payer’s designated appeals portal or mail it to their specific appeals address with delivery tracking.

A timely filing limit is the strict deadline set by an insurance payer or government program for a healthcare provider to submit a claim after rendering services.

If a claim is submitted after this deadline, the insurance company will deny it, and the provider usually cannot bill the patient for the balance.

Common Limits by Payer Type

• Medicare: 12 months (one calendar year) from the date of service.
• Medicaid: Varies completely by state, ranging from 90 or 95 days up to 12 months.
• Commercial Insurers (like Aetna, Cigna, or UnitedHealthcare): Typically 90 to 180 days depending on the specific contract and network status.

Key Rules

• The clock usually starts on the date of service (or the discharge date for inpatient care).
• Rejected or returned claims do not pause the clock; the original deadline still applies.
• Exceptions are rare and typically limited to system errors by the payer or retroactive Medicare/Medicaid eligibility.

Yes, you can appeal a timely filing denial if you have proof that the claim was submitted on time or a valid "good cause" reason for the delay.

When You Can Appeal

• Proof of original submission: You have an electronic data interchange (EDI) report, clearinghouse confirmation, or receipt showing the claim went out before the deadline.
• Good cause exceptions: Extenuating circumstances caused the delay, such as severe illness, natural disasters, or delayed notification of secondary insurance coverage from the patient.
• State or federal rules: Some state laws or government programs require insurers to accept late claims if valid justification or proof of secondary coordination of benefits (COB) is provided.

Steps to Appeal

1. Gather documents: Collect the original claim form, the denial letter (such as denial code CO 29), the Explanation of Benefits (EOB), and your clearinghouse transmission report.
2. Write an appeal letter: Draft a clear letter explaining the reason for the delay or providing the electronic tracking details. Cite specific sections of the California Medical Association or your payer manual if local regulations apply.
3. Submit the package: Send the appeal via the insurer's provider portal or mail it directly to their designated appeals address before their appeal deadline expires.

The Medicare timely filing limit is 12 months (one full calendar year) from the date the service was provided under 42 CFR § 424.44.

Key Rules and Measurement

• Receipt Date: Medicare measures timeliness by the date your Medicare Administrative Contractor (MAC) physically or electronically receives the claim—not the date you mail, postmark, or submit it in your billing software.
• Calculation: A service provided on March 31 must be received by Medicare on or before March 31 of the following year. If the deadline lands on a weekend or a federal holiday, it moves to the next business day.
• Original vs. Advantage: Original Original Medicare strictly uses the 12-month federal rule. Private Medicare Advantage plans set their own individual limits, which often range from 90 to 180 days.

Denials and Exceptions

• No Appeals: If Medicare denies a claim for late filing (such as denial code CO-29), the decision is not an "initial determination," meaning you cannot use the standard appeals process.
• Limited Exceptions: Exceptions are rare and granted only for specific situations like administrative/system errors, retroactive Medicare entitlement, or retroactive disenrollment from a Medicare Advantage plan.

The timely filing limit (TFL) for Original Medicare is 12 months (one calendar year) from the date of service.

Original Medicare Rules

• Deadline: Claims must be received by the Medicare Administrative Contractor (MAC) within 365 days of the service date.
• Anchor Date: For Part B professional claims, it starts from the exact "From" date of service. For Part A institutional claims, it counts from the "Through" date of the claim span.
• Receipt Date: Medicare looks at the date the claim is received, not the date it was mailed or submitted.
• Denials: Missing the deadline by even a single day results in a denial (using code CO-29), and late filing denials generally cannot be appealed through standard channels.

Medicare Advantage (Part C) Differences

• Private insurance companies run Medicare Advantage plans.
• While CMS maintains a 12-month federal floor for non-contracted providers, individual network contracts often require much shorter deadlines—frequently between 90 to 180 days depending on the specific insurance provider (such as Aetna, Humana, or UnitedHealthcare).

Limited Exceptions

Medicare allows rare extensions past the 12-month limit under strict CMS guidelines, which include:

• Government or contractor administrative errors
• Retroactive Medicare entitlement
• Natural disasters or localized emergencies