OwedAppeal

Denial codes

CO-29

Denied because the claim was filed late

The provider sent the claim after the plan's deadline. That's the provider's responsibility. Under most network contracts an in-network provider can't bill you for a claim they filed late.

Official meaning (X12 code 29): The time limit for filing has expired.

Who pays

CO-29. Contractual obligation: the provider's contract with your plan makes this the provider's write-off. An in-network provider generally can't bill you for a CO amount.

What to do

  1. Call the provider's billing office and ask them to write off the balance.
  2. If they had proof of timely filing (for example a rejected first submission), they can appeal.
  3. If you're billed anyway, send a written dispute citing the CO group code.

If you appeal

Late claim submission is the provider's responsibility. In-network providers' contracts usually bar them from billing you for claims they filed late. Ask the provider to write off the balance.

What the appeal asks for: Reconsider this timely-filing denial; the delay was not caused by the member. If the denial stands, confirm in writing that the member is not liable under the provider's network agreement.

Deadlines for the first appeal

employer plan
180 days from the notice
ACA Marketplace plan
180 days from the notice
Medicare Advantage plan
65 days from the notice
Original Medicare
120 days from the notice
Medicaid
60 days from the notice

The date printed on your notice controls. Urgent care can be appealed on an expedited (72-hour) basis.

What the data show

11.5%Only 11.5% of denied Medicare Advantage prior authorization requests were appealed in 2024. KFF, 2024 data
80.7%80.7% of appealed Medicare Advantage prior authorization denials were partially or fully overturned in 2024. KFF, 2024 data
<1% (262,982 appeals)Fewer than 1% of denied in-network marketplace claims were appealed in 2024 (at least 262,982 appeals). KFF, 2024 data
66% upheldInsurers upheld 66% of denials on internal appeal in 2024 (165,863 denials). KFF, 2024 data
25%25% of in-network marketplace denials were for administrative reasons, the most common reason other than 'other'. KFF, 2024 data

Averages across all denials; not a prediction for yours.

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General information, not legal or medical advice. Owed is a document-preparation and sending service, not a law firm.