CO-29 Denial Code: Timely filing limit expired
The payer says the claim arrived too late. The trap: the clock runs from date of service to FIRST submission — resubmissions and payer-caused delays don't reset or count against you.
Why it happens
- Claim genuinely filed after the deadline (staff backlog, credentialing holds)
- Original claim WAS timely but was rejected/lost and the resubmission is being measured instead
- Payer received it on time but their intake mis-dated it
- COB confusion — waiting on primary EOB pushed secondary filing late
How to fix it, step by step
- Never write these off automatically — pull proof of the ORIGINAL submission (clearinghouse acceptance report, EDI 999/277 acknowledgment)
- Appeal with a timeline table: date of service, each submission date, each payer response, with proof attached
- Cite the payer's own timely-filing rule — measured from first submission
- For COB cases, attach the primary EOB date showing you filed secondary promptly after
Is it worth working?
High when you have submission proof — timely-filing denials with clearinghouse evidence are among the most winnable appeals.
High when you have submission proof — timely-filing denials with clearinghouse evidence are among the most winnable appeals.
How much is your practice writing off to denials like this?
Send 6 months of remittance files (3 clicks in your billing software) — get a free one-page scorecard of your denied dollars, what's recoverable, and your top payer patterns — within one business day of receiving your files. Recovery is contingency-only: no fee unless money posts.
Get the free denial auditMore codes: the Claimmender denial-code library.