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CO-145 Denial Code (Deactivated): Premium Withholding

CO-145 reported an amount withheld from a provider payment as premium payment withholding. X12 deactivated it, and its notes instruct payers to use Group Code CO with CARC 45.

X12 deactivated CARC145 on April 1, 2008. Payers should no longer use it on new remittances, but it can still appear on older ERAs, corrected claims, and appeals.

Code: CO-145 (CARC 145)
Status: Deactivated StoppedApril 1, 2008 (in use since June 30, 2002).
Code set: Claim Adjustment Reason Codes (CARC)
Group codes: CO (Contractual Obligation): The withholding was a contractual matter between payer and provider, not a patient liability.
Official description: Premium payment withholding
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What CO-145 meant

CARC 145 described money kept back from the provider’s payment under the label “premium payment withholding.” The official text gives no more detail than that. It was a relatively short-lived code, and the amount was treated as a contractual matter.

What replaced it

X12’s note says to use Group Code CO and code 45, so CO-45 is the named replacement. Payers that hold back part of a payment for other reasons have separate active codes: CO-104 for managed care withholding and CO-245 for performance program withholds.

If you still see CO-145

It will only appear in older remittances. Check your contract for any clause about withholds or premium offsets, and confirm whether the withheld amount was ever returned or settled at year-end. If your contract does not allow it, ask the payer to explain the basis. Otherwise post it as a contractual adjustment, not a patient balance.

CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The replacement X12 names, used with group CO.
CO-104 (Managed care withholding.): Managed care withholding, a separate active withholding code.
CO-245 (Provider performance program withhold.): Provider performance program withhold.

CO-145 FAQ

What was premium payment withholding?

The code's text does not define it further. It described an amount held back from the provider's payment under the payer arrangement, which X12 later decided belonged under the general contractual code 45.

Can I bill the patient for a CO-145 amount?

No. It was a contractual item under the CO group and was never patient cost-sharing.

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