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CO-W8 Denial Code (Deactivated): Zero Relative Value

CO-W8 meant the procedure had a relative value of zero in the jurisdiction's fee schedule, so no payment was due. X12 deactivated it and its notes direct payers to code P19.

X12 deactivated CARCW8 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-W8 (CARC W8)
Status: Deactivated StoppedJuly 1, 2014 (in use since June 2, 2013).
Code set: Claim Adjustment Reason Codes (CARC)
Group codes: CO (Contractual Obligation): A zero-value service was a provider adjustment and generally not billable to the injured worker.
Official description: Procedure has a relative value of zero in the jurisdiction fee schedule, therefore no payment is due.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What CO-W8 meant

Many workers’ compensation fee schedules calculate payment from relative values. When a billed procedure carried a relative value of zero in the jurisdiction’s schedule, the math produced no payment. CARC W8 explained that result, which was not a denial of the care so much as a valuation outcome.

What replaced it

X12’s note says to use code P19. CO-P19 now reports the same zero-value result. Similar non-payment outcomes include CO-P14, for a service included in another one, and CO-246, for codes that exist purely for reporting.

If you still see CO-W8

It will be on older workers’ compensation remittances. Confirm the procedure code billed was correct and that it truly has zero value in the schedule for that date. If a different code more accurately describes the service, rebill it. Otherwise, write off the line and flag the code so staff know it is not separately payable in that jurisdiction.

CO-P19 (Procedure has a relative value of zero in the jurisdiction fee schedule, therefore no payment is due.): Named replacement: procedure has a relative value of zero in the jurisdiction fee schedule.
CO-P14 (The Benefit for this Service is included in the payment/allowance for another service/procedure that has been performed on the same day.): Included in the allowance for another service on the same day, property and casualty only.
CO-246 (This non-payable code is for required reporting only.): A non-payable code used for required reporting only.

CO-W8 FAQ

Why would a procedure have a relative value of zero?

Some services are considered part of other services, are reporting-only codes, or are not separately valued in the fee schedule the jurisdiction adopted.

Is a W8 amount ever payable?

Not under the fee schedule as written. If you think the wrong code was used, correct it; otherwise the adjustment is final.

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