CO 29 Denial Code: Timely Filing Expired. Can You Still Get Paid?

CO 29 reads "the time limit for filing has expired." Every payer contract sets a window for submitting claims after the date of service; miss it and the claim denies in full, with no patient billing allowed. It's the most unforgiving code in billing: the care was delivered, the claim may be perfect, and the revenue is still zero.

CO 29 at a Glance

Question	Answer
Is it a true denial?	Yes, and a total one; late claims pay nothing.
Can you bill the patient?	No. Provider filing failures are contractually the provider's loss.
Is it appealable?	Only with proof the claim was originally submitted on time, or documented good cause.
Prevention	Completely preventable: it's a workflow deadline problem, not a payer judgment.

Typical Timely Filing Limits

Payer Type	Typical Limit	Notes
Medicare	12 months from date of service	The most generous major payer
Medicaid / MCOs	90 days to 1 year, state-dependent	Some state programs run as short as 90 days
Commercial plans	90 to 180 days commonly	Contract-specific; some allow 12 months
Corrected claims / appeals	Often 30-90 days from the denial	A separate, shorter clock many teams miss

The second clock is the silent killer: a claim denied for a fixable reason (like CO 16) that sits in a work queue can pass the corrected-claim deadline even though the original was filed on time.

Appealing CO 29

Two arguments work:

1. Proof of timely original submission. Clearinghouse acceptance reports, electronic claim receipts, or certified mail records showing the claim went out inside the window. This wins when the payer lost or misprocessed the original. Keep acceptance reports for every batch; they are your evidence.
2. Good cause. Retroactive eligibility (a Medicaid approval backdated past the filing window), incorrect payer information supplied by the patient with prompt filing once discovered, or documented payer system errors. Payers grant these narrowly, but they do grant them.

What doesn't work: "we were short-staffed." Volume of pending work is never accepted as good cause.

Prevention: Deadlines as Data

• Submit within 24-48 hours of the encounter. A claim filed the same week can miss no deadline anywhere.
• Track every unresolved claim against its specific payer clock, not a generic 90-day assumption.
• Work denials by deadline, not by age. A 45-day-old denial with a 60-day correction window outranks a 90-day-old one that's already dead.
• Watch the aging report. AR over 90 days is where CO 29 write-offs are born; our AR management service prioritizes follow-up by dollar value and filing deadline for exactly this reason.

More from the library: the complete denial codes list, CO 45 (fee schedule adjustments), and PR 119 (benefit maximum).