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CO-218 Denial Code (Deactivated): Entitlement to Benefits

CO-218 meant a workers' compensation payer adjusted the claim based on the injured worker's entitlement to benefits. X12 deactivated it and its notes direct payers to code P6.

X12 deactivated CARC218 on July 1, 2014. Payers should no longer use it on new remittances, but it can still appear on older ERAs, corrected claims, and appeals.

Code: CO-218 (CARC 218)
Status: Deactivated StoppedJuly 1, 2014 (in use since January 27, 2008).
Code set: Claim Adjustment Reason Codes (CARC)
Group codes: CO (Contractual Obligation): The adjustment followed the carrier's entitlement decision and was not billed to the patient under this code.
Official description: Based on entitlement to benefits. Note: If adjustment is at the Claim Level, the payer must send and the provider should refer to the 835 Insurance Policy Number Segment (Loop 2100 Other Claim Related Information REF qualifier 'IG') for the jurisdictional regulation. If adjustment is at the Line Level, the payer must send and the provider should refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment information REF). To be used for Workers' Compensation only
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What CO-218 meant

CARC 218, used only in workers’ compensation, explained that payment was adjusted because of the injured worker’s entitlement to benefits. For example, the carrier might accept the injury but limit which treatment or which time period qualifies. The adjustment reflected that entitlement decision rather than pricing or coding.

What replaced it

X12’s notes say to use P6. CO-P6 keeps the same wording in the property and casualty P-series. When the whole claim is rejected rather than limited, carriers use CO-P4. General jurisdictional rules and payment policies fall under CO-P13.

If you still see CO-218

It will appear only on older workers’ compensation remittances. Review the adjuster’s correspondence to understand what the worker is entitled to and for which dates. If treatment was provided outside the accepted scope, ask whether a request to expand it is pending. Otherwise, follow the state’s rules for whether the balance may be billed to other coverage or the patient.

CO-P6 (Based on entitlement to benefits.): Named replacement: based on entitlement to benefits.
CO-P4 (Workers' Compensation claim adjudicated as non-compensable.): Workers' compensation claim adjudicated as non-compensable.
CO-P13 (Payment reduced or denied based on workers' compensation jurisdictional regulations or payment policies, use only if no other code is applicable.): Reduced or denied based on workers' compensation jurisdictional regulations or payment policies.

CO-218 FAQ

What does entitlement to benefits mean here?

It refers to whether, and to what extent, the injured worker is entitled to medical benefits under the workers' compensation claim. If entitlement is limited or ended, payment for the service is affected.

Where do I find the rule behind the decision?

The code text directs payers to report the jurisdictional regulation in specific 835 reference fields at the claim or line level. Check those, then ask the adjuster if anything is unclear.

Important: read before using this information

This page is general educational information about a standard industry code set. It is not medical billing, coding, legal, reimbursement, or compliance advice, and it does not create a professional or advisory relationship with ClaimsRevenue.

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