Medicare Denied Claim for Late Filing (Timely Filing)

What This Means

Medicare denied this claim because it was submitted after the filing deadline. This usually appears as CARC CO-29, “the time limit for filing has expired”. For Original Medicare, providers generally have one calendar year from the date of service to submit the claim (42 CFR 424.44). Medicare Advantage plans set their own provider filing deadlines by contract, which can be shorter.

This is almost always a billing office issue, not something you caused.

Why This Happens

• The provider’s billing office missed the deadline. Claim submission is the provider’s responsibility. Staffing changes, system errors, or administrative backlogs can cause claims to be filed late.
• There was a delay in processing other insurance first. If you have other insurance in addition to Medicare, the primary insurer needs to process the claim first. Delays there can push the Medicare filing past the deadline.
• A claim was resubmitted after correction but too late. If an original claim was rejected for errors and the corrected version was resubmitted after the deadline, the timely filing limit may have passed.
• You changed insurance. If you recently switched from Medicare Advantage to Original Medicare (or vice versa), there can be confusion about which entity to bill and when.

Should You Appeal?

The more important question: should you owe money for this?

If your provider accepted assignment (agreed to Medicare’s payment terms) and they missed the filing deadline, they generally cannot bill you for the service — a claim denied solely for the provider’s late filing is the provider’s responsibility, not yours. Contact your provider’s billing office and ask whether they accepted assignment.

What To Do Next

1. Contact your provider’s billing office. Tell them the claim was denied for timely filing. They may be able to resubmit with documentation showing it was originally filed on time, or they may need to write off the charge.
2. Ask whether they accepted assignment. If they did, they should not bill you for their late filing.
3. Check if you have other insurance. If another insurer caused the delay, your provider’s billing office may be able to request an exception from Medicare.
4. If you’re being billed unfairly, contact 1-800-MEDICARE (1-800-633-4227) to report the issue, or contact your State Health Insurance Assistance Program (SHIP) for free help.

Sources

• eCFR — 42 CFR 424.44: Time limit for filing claims — the one-calendar-year Medicare filing deadline
• CMS: Medicare Claims Processing Manual, Chapter 1, Section 70 — timely filing requirements and limited exceptions
• Medicare.gov: Does Your Provider Accept Medicare as Full Payment? — assignment, and why a provider can’t bill you for their own late filing
• X12: Claim Adjustment Reason Codes — definition of CO-29
• Medicare.gov: Filing a Complaint About Your Medicare Coverage

Frequently Asked Questions