OwedAppeal

Denial codes

CO-252

More documentation needed

The plan needs records before it will decide. The provider usually sends them; nothing is owed yet.

Official meaning (X12 code 252): An attachment/other documentation is required to adjudicate this claim/service.

Who pays

CO-252. 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. Ask the provider to send the requested records.
  2. Ask the plan what exactly is missing (the remark code helps).

If you appeal

Denials for a wrong code, missing modifier or mismatched diagnosis are usually fixed when the provider's billing office corrects and resubmits the claim. Call them first and ask them to do it; still file the appeal before the deadline as a backstop.

What the appeal asks for: Reprocess this claim once the provider submits corrected coding; the service itself was covered and medically necessary.

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.

Not sure this applies to you?

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