CARC Denial Code Reference Guide

Claim Adjustment Reason Codes (CARCs) tell you why a payer adjusted or denied a claim. Each code below includes what it means, why it happens, and how to resolve it. These codes follow the X12/ANSI standard used by all U.S. commercial and government payers.

Contractual Obligation (CO) Codes

CO-4

Procedure code inconsistent with modifier or bundled

CO-6

Procedure/revenue code not covered under plan

CO-11

Diagnosis inconsistent with procedure

CO-14

Date of service outside coverage period

CO-15

Authorization missing, invalid, or expired

CO-16

Claim/service lacks information or differs from payer records

CO-18

Duplicate claim/service

CO-19

Workers' compensation claim

CO-21

Expense incurred after coverage terminated

CO-22

Coordination of benefits adjustment

CO-23

Payment adjusted: charges exceed fee schedule

CO-25

Code edit violation

CO-26

Expense incurred before coverage began

CO-27

Expenses not covered by plan

CO-29

Timely filing limit expired

CO-31

Patient not our insured

CO-32

Our contract does not cover this

CO-33

Requested information not received

CO-39

Services denied at time of discharge

CO-41

Contractual agreement exceeded

CO-42

Charges exceed contracted/legislated fee

CO-44

Prompt payment discount applied

CO-45

Exceeds fee schedule/maximum allowable

CO-46

Not deemed a medical necessity

CO-47

Payment suspended pending review

CO-48

Non-covered service per state regulation

CO-50

Non-covered service (not deemed medical necessity)

CO-55

Multiple procedure reduction applied

CO-97

Benefit included in another service/procedure

CO-102

Medical necessity not established

CO-103

Not covered under patient's current plan

CO-119

Benefit maximum reached for this period

CO-167

Diagnosis not covered by this payer

CO-197

Precertification/notification/authorization absent

CO-204

Service/equipment/drug not ordered by provider

Other Adjustment (OA) Codes

OA-23

COB adjustment (informational)

Patient Responsibility (PR) Codes

Non-covered charge (patient responsibility)

Stop chasing denial codes manually

Altair flags denials in real time and tells your team exactly how to fix them.

Check Out How

This content is for informational purposes only and does not constitute legal, medical, or billing advice. Always verify current payer policies before acting on denial code information. Payer rules change frequently.