The official definition
“The time limit for filing has expired”
That is the verbatim definition of CARC 29 from the X12 Claim Adjustment Reason Code set, the standardized codes every insurer uses on EOBs and remittance advices. The letters in front of the number are the group code. CO: Contractual Obligation: an adjustment between the provider and the insurer. An in-network provider should not bill you for CO amounts.
What it means in plain English
The provider submitted the claim after the insurer's filing deadline. This is the provider's error: meeting filing deadlines is a basic contractual obligation between them and the insurer. You should not owe a dime because their billing office missed a date.
What to check on your EOB
- Whether the provider is billing you for the denied amount. For in-network providers, that generally violates their contract with the insurer.
- The claim's submission history, if you can get it: was there an earlier submission or an insurer request for more information that affects the deadline?
What to do next
- Do not pay a bill resulting from a timely filing denial.
- Tell the provider: this claim was denied for timely filing, and under your contract with the insurer you cannot bill me for it.
- If the provider insists, file a complaint with your state insurance department and the insurer's provider relations team.
Who's responsible
Provider, entirely. Most denials carry a clear owner. Knowing whether the fix belongs to you, your doctor, or the billing office is half the battle. If it's the provider's error, you should not be paying for it.
Want the fundamentals first? Start with how to read an EOB and the 7 most common billing errors. This page is general information about standardized denial codes, not legal or medical advice.
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