CO-29 denial code
The payer received the claim after its filing deadline.
“The time limit for filing has expired.”
Start 01/01/1995 · X12 adjustment reason code list
What it usually means in behavioral health
Medicare generally requires claims within 12 months of the date of service. Commercial filing limits come from the provider contract, and Medicaid limits vary by state; many are far shorter than Medicare's.
Behavioral health claims age quietly in rejections that never became real claims, in authorization disputes, and in claims waiting on a credentialing fix.
Common causes
- Claim rejected at the clearinghouse and never corrected
- Held waiting on an authorization, credentialing, or coordination-of-benefits fix
- Filed to the wrong payer first
- Corrected claim sent after the corrected-claim window
Correct and resubmit, or appeal?
Appeal only with proof the claim was filed on time, such as an accepted clearinghouse report or the payer's acknowledgment, or with a contract or rule exception. Without proof, CO-29 is generally a write-off.
What to do
Search for proof of timely submission: clearinghouse acceptance reports and payer acknowledgments.
Check the contract for exceptions, such as retroactive eligibility or coordination delays.
Appeal with the proof, or write off and fix the aging process.
Work rejections daily; a rejection is not a filed claim.
Often seen with
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