CARC 18Duplicate claimDuplicate service line
CARC 18: Duplicate Claim or Service
A duplicate adjustment means the payer believes the same service was already submitted or adjudicated. The correct action depends on whether the prior claim is paid, pending, denied, voided, or materially different.
First checks
- 1Find the original payer claim number and status.
- 2Compare patient, provider, code, modifier, units, charge, and date.
- 3Check whether a corrected claim was sent as a new original.
Resolution path
- 01Do not send another unchanged original claim.
- 02If the prior claim is correct and pending or paid, close or post appropriately.
- 03If correction is needed, use the payer's replacement or void process.
- 04Dispute only when the claims are demonstrably distinct.
Evidence packet
- Original and current claim comparison
- Payer claim-history screen
- Distinct encounter, site, provider, or service documentation
Prevent the next denial
Lock resubmission while a claim is pending, reconcile clearinghouse and payer claim IDs, and require replacement or void indicators for true corrections.
Official sources
Use the current payer notice, contract, code set, policy, and filing instructions. This guide is educational and does not determine patient liability or appeal rights for an individual claim.