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CO-65 Denial Code (Deactivated): Procedure Code Corrected

CO-65 meant the payer decided the procedure code on the claim was incorrect and paid based on the code it considered correct. X12 deactivated it without naming a successor.

X12 deactivated CARC65 on October 16, 2003. Payers should no longer use it on new remittances, but it can still appear on older ERAs, corrected claims, and appeals.

Quick facts

Code
CO-65 (CARC 65)
Status
Deactivated StoppedOctober 16, 2003 (in use since January 1, 1995).
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): Any difference between the billed and recoded amount was a provider adjustment.
Official description
Procedure code was incorrect. This payment reflects the correct code.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-65 meant

CARC 65 told the provider that the payer had recoded the service. The procedure code on the claim was judged incorrect, and the payment on the remittance was calculated using the code the payer believed described the service. In effect, the payer corrected the claim rather than rejecting it.

What replaced it

X12 did not name a replacement, and current practice varies by payer. Some payers deny the line and ask for a corrected claim instead of recoding it. Active codes you may see in similar situations include:

  • CO-150 when documentation does not support the level of service billed.
  • CO-181 when the code billed was not valid on the date of service.
  • CO-16 with a remark code for other billing errors.

If you still see CO-65

It is a historical code, so it mostly shows up in archived remittances. On such a claim, compare the code the payer paid with the one you billed and with the clinical note.

If the payer’s code was right, post the payment, write off the difference as a contractual adjustment, and correct your charge setup or coding habits so it does not recur. If your original code was supported, gather the documentation and dispute the change through the payer’s reconsideration process.

  • CO-150 (Payer deems the information submitted does not support this level of service.): The information submitted does not support the level of service billed.
  • CO-181 (Procedure code was invalid on the date of service.): The procedure code was invalid on the date of service.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Claim lacks information or has billing errors, with a remark code giving specifics.

CO-65 FAQ

Did CO-65 mean the claim was denied?

Not necessarily. The payer processed the claim but under a different procedure code than the one billed, so the payment may have been lower or higher than expected.

Should I accept the payer's corrected code?

Review it against the documentation. If your original code was correct, you can dispute the change through reconsideration or appeal. If the payer was right, update your coding so future claims are billed correctly.