CO 210 denial code
Claim adjustment reason code 210. Often reported as CO 210.
Authorization not obtained in time
Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated .
What 210 means
An authorization or precertification was obtained, but later than the payer's rules allow, so payment was reduced or denied.
The difference from a missing authorization is timing. The approval exists, but it was requested or received after the window the plan sets, such as after an admission or after the service date.
Some plans apply a penalty reduction instead of a full denial. Check the plan's notification rules for the service type.
Group codes seen with 210
On a remittance, 210 comes after a group code. These are the ones it is most often reported with:
- CO 210 (Contractual Obligation): The provider's side of the ledger. The reduction comes from the payer contract or a rule the provider has to follow, and the patient normally cannot be billed for it.
The payer chooses the group code for each adjustment, so the same reason code can appear with another group code on your remittance. Read the two together. More about group codes.
Common causes
- An inpatient admission was reported to the payer after the plan's notification window.
- A retro authorization was requested after the service and the payer counted it as late.
- A change in the procedure during the visit was reported to the payer too late.
What to do next
- Check the date the authorization was requested against the payer's notification deadline.
- Appeal with proof of timely notice, such as fax confirmations or portal timestamps, if you have it.
- Explain any emergency or after-hours circumstances that delayed the request when appealing.
- Tighten intake workflows so notifications go out within the plan's window.
Related codes
- 197 (reason code) No prior authorization on file
- 198 (reason code) Authorization limits exceeded
- 29 (reason code) Timely filing limit has passed
Source
Official wording: X12 Claim Adjustment Reason Codes list. The explanation on this page is our own plain-English wording, not the X12 text.
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