Claim Denial Code Library
Search 60+ Claim Adjustment Reason Codes (CARCs). Learn what each code actually means, why payers trigger it, and the exact clinical documentation required to overturn it.
Highest-Volume CARC Denial Codes
Updated for CY2026Precertification / Authorization / Notification absent
The insurer claims they never authorized this care before it happened, or the authorization on file does not match the exact CPT code billed.
Claim lacks information or has billing errors
Something was missing from the electronic claim form — a modifier, NPI, diagnostic cross-reference, or attachment.
The benefit for this service is included in another service
The insurance company bundled this service into another procedure performed on the same day, claiming it was included in the base fee.
These are non-covered services because this is not deemed a medical necessity
The insurer claims the patient did not need this treatment, test, or level of care based on their clinical policy.
The time limit for filing has expired
The insurer claims you took too long to submit the claim or appeal, so they refuse to review it.
Charge exceeds fee schedule / maximum allowable amount
Standard contractual write-off, but frequently conceals systematic payer underpayments below contracted fee schedules.
This care may be covered by another payer per coordination of benefits
The insurance company thinks another insurance plan should pay first and refuses to pay until you prove otherwise.
Exact duplicate claim / service
The insurer thinks this is a duplicate bill and automatically rejected it without looking.
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