Denial Code CO 18

Denial Code CO 18 – Duplicate Claim/Service

Insurance company will denote the claim or service with denial code CO 18 – Duplicate Claim/Service, when they have already adjudicated the original claim or service previously.

Claim or service can be denied with denial code 18 for the following reasons:

• When provider renders medical service once, but the claim or service billed more than once to the insurance company.
• On the same day, if patient receives the same service by two different providers and insurance already processed another provider claim prior to your claim.
• On the same day, same service performed twice by the same provider.
• If provider performs same service bilaterally, but claim submitted without indicating a appropriate modifier.
• When corrected claim resubmitted without indicating it as corrected claim.

Denial Code CO 18 resolutions:

Now let us see the above reasons along with examples to find the best solution to get rid of the denial code CO 18.

1. When provider renders medical service once, but the claim or service billed more than once to the insurance company.

When provider bills the claim twice to the insurance company, then insurance company will adjudicate the original claim or service and deny the other claim with denial code CO 18

Resolution: In this case we need to check the original claim adjudicated towards denial or it’s paid by the insurance company. If it is denied, then need to take action based on the denial code we received for the original claim.

• On the same day, if patient receives the same service by two different providers and insurance already processed another provider claim prior to your claim.

When patient receives the same medical treatment on the same day with two different medical doctors.  And if the other doctor claim adjudicated and paid prior to your claim or service, then insurance company will deny your claim or service with denial code CO 18.

Resolution: In this case we need to reach out claims department and request the representative to send the claim back for reprocessing as same service performed by two different providers. If rep disagree, then we need to appeal your claim along with supporting documents.

• On the same day, same service performed twice by the same provider.

Modifier plays an important role in the above scenario. Because when same service performed by the same provider more than once on the same day claim billed without indicating a modifier, then insurance company will adjudicate one claim and the other claim will be denied with denial code CO 18.

Resolution: In this case we need to append modifier 76 or check with coding team for the appropriate modifier. Also make sure to submit the claim as corrected claim.

If claim already submitted with appropriate modifier, but still denied for the following reason. Then we have to appeal the claim with supporting documentation for reimbursement.

• If provider performs same service bilaterally, but claim submitted without indicating an appropriate modifier.

 For example, let us consider provider performs same treatment for both the leg on the same day and claim submitted without indicating a modifier LT and RT or 50 for the line items, then insurance will process one claim or service and others get denied with denial code CO 18.

Resolution: Please review the medical records and append the appropriate modifier RT and LT or 50.

• When corrected claim resubmitted without indicating it as corrected claim.

Whenever you correct the claim, then it is very important to indicate those corrected claim as “Corrected claim”. If it is not indicated, then insurance company will process as normal claim and deny the claim with denial code CO 18.

Medical Billing Denials and actions – Top Denial codes Solutions (medicalbillingcycle.com)