Denial code

CARC 18 denial code: meaning & whether to appeal

CARC 18: the exact X12 wording, how it is classified, and whether it is worth appealing.

Appealant EditorialX12 verified3 min read

What CARC 18 means

Exact duplicate claim/service (Use only with Group Code OA except where state workers' compensation regulations requires CO)

Verbatim description from the official X12 Claim Adjustment Reason Codes list.

Classification

Routing category: duplicates

Appealability verdict

Verify duplicate status first

What to know

Confirm whether the claim is a true duplicate before responding. If the payer's duplicate flag is wrong, respond with proof of the distinct service or of the original timely submission.

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