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CO-210 Denial Code: Late Pre-Certification

CO-210 means the payer adjusted payment because the pre-certification or authorization was not received in a timely fashion. An authorization may exist, but it was requested or submitted after the payer's deadline, such as after the service or past a notification window.

Quick facts

Code
CO-210 (CARC 210)
Status
Active In use since July 9, 2007.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider is responsible for the late authorization. The adjusted amount generally cannot be billed to the patient.
  • PR (Patient Responsibility): Less common. Some plans make the member responsible for obtaining authorization, and a late request can shift a penalty to the patient under plan terms.
Official description
Payment adjusted because pre-certification/authorization not received in a timely fashion
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-210 means

CARC 210 reads: payment adjusted because pre-certification/authorization not received in a timely fashion. The key word is timely. The payer is not saying the service was never authorized; it is saying the request or notification came in after its deadline.

Many payers require authorization before a scheduled service and notification within a set period after an urgent or emergency admission. When the request lands after the service, or after that notification window, some payers deny the claim and others apply a reduction or penalty. Both are reported as CARC 210. Because the adjustment can be partial, check whether the line was denied in full or only reduced.

Common causes

  • Authorization requested after the date of service, for example when a test was added the same day.
  • Missed admission notification for an inpatient stay or observation-to-inpatient change.
  • Extension requested late, after the original authorization period had ended but treatment continued (common in therapy and behavioral health).
  • Request sent to the wrong entity, such as the health plan instead of its delegated utilization management vendor, so the correct one received it late.
  • Retro-authorization granted but flagged as late under plan rules.

How to fix it

  1. Confirm the authorization details in the payer portal: request date, approval date, effective dates, and the units or services covered.
  2. Compare with your records. Look for fax confirmations, portal receipts, or call reference numbers showing when you actually submitted.
  3. If your records show a timely request, file a reconsideration or appeal with that evidence. Include the authorization number (box 23 on the CMS-1500).
  4. If the authorization number or dates were wrong on the claim, correct them and send a corrected claim (frequency code 7) rather than an appeal.
  5. If the request truly was late, ask whether the payer has a late-notification exception, such as for emergencies or for retroactive eligibility, before writing off the amount.
  6. Do not bill the patient for a CO-210 amount.

For more on building authorization workflows, see authorization and referral denials.

How to prevent it

  • Track authorizations by start date, end date, and remaining units, with alerts before expiration.
  • Build admission-notification tasks into the admitting workflow, including weekends and holidays.
  • Check whether the plan delegates authorizations to a vendor and send requests to the right place.
  • Keep proof of every submission, with a date and time stamp.
  • Recheck authorization when services change on the day of the visit.

Specialty notes

Therapy, behavioral health, and home health often work under visit-limited authorizations. CO-210 in these settings commonly follows a lapse between the end of one authorization and the approval of the next, so request continuations well before the current period ends.

Remark codes that may appear with CO-210

  • N54 (Claim information is inconsistent with pre-certified/authorized services.): Shows the claim does not line up with what was authorized, which may reveal the authorization's actual effective dates.
  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Points to plan documents describing notification deadlines.
  • N381 (Alert: Consult our contractual agreement for restrictions/billing/payment information related to these charges.): Points to your contract's authorization and notification requirements.
  • CO-197 (Precertification/authorization/notification/pre-treatment absent.): No authorization was on file at all, rather than one that arrived late.
  • CO-198 (Precertification/notification/authorization/pre-treatment exceeded.): An authorization existed, but the services exceeded what it approved.
  • CO-39 (Services denied at the time authorization/pre-certification was requested.): The authorization request was denied outright when submitted.
  • CO-29 (The time limit for filing has expired.): Late claim filing, which is a different deadline from late authorization.

CO-210 FAQ

What is the difference between CO-197 and CO-210?

CO-197 means no authorization was found. CO-210 means authorization was obtained, or notification was given, but after the payer's required timeframe.

Can I appeal a CO-210 denial?

Yes, if you have proof that notification or the authorization request was made on time, such as a fax confirmation, portal submission receipt, or call reference number. Without that proof, appeals are less likely to succeed.

Are emergency admissions subject to CO-210?

Many plans allow a short window after an emergency admission to notify them, and a missed window can trigger CO-210. The specific window varies by payer and contract.

Can I bill the patient for a CO-210 adjustment?

Not under the CO group. The provider bears the loss. Check the plan terms only if the payer reports the amount as PR.