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CO-B19 Denial Code (Deactivated): Review Org Finding

CO-B19 meant the claim or service was adjusted because of a review organization's finding. X12 deactivated it without naming a successor; CARC 216 now covers adjustments based on a review organization's or the payer's findings.

X12 deactivated CARCB19 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.

Code: CO-B19 (CARC B19)
Status: Deactivated StoppedOctober 16, 2003 (in use since January 1, 1995).
Code set: Claim Adjustment Reason Codes (CARC)
Group codes: CO (Contractual Obligation): The provider absorbed the adjustment unless the finding was overturned.
Official description: Claim/service adjusted because of the finding of a Review Organization.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What CO-B19 meant

CARC B19 told the provider that an outside review organization had examined the claim or the care behind it, and its conclusion changed the payment. That could mean a denied inpatient day, a reduced level of care, or a service found unnecessary. The adjustment was the payer carrying out the reviewer’s decision.

What replaced it

X12 did not name a replacement. The active CO-216 now covers adjustments based on the findings of a review organization or the payer itself. When the finding concerns medical necessity, payers may use CO-50. After a reconsideration, CO-193 indicates the original decision stood.

If you still see CO-B19

Expect it only on older remittances. For any review-based adjustment, request the reviewer’s written determination so you know exactly what was found. If the medical record supports the care provided, file a reconsideration within the stated time limit. If not, accept the adjustment and share the finding with the clinical team.

CO-216 (Based on the findings of a review organization or the payer's findings.): Based on the findings of a review organization or the payer's own findings.
CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): Not deemed a medical necessity by the payer.
CO-193 (Original payment decision is being maintained.): Original payment decision maintained after review.

CO-B19 FAQ

What is a review organization?

An entity that reviews care for appropriateness or quality on behalf of a payer or program. In Medicare, quality improvement organizations have played this role for inpatient stays.

Can a review finding be challenged?

Usually, through the review organization's or payer's reconsideration process, within its deadlines. Submit the medical record and a clinical explanation addressing the finding.

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