Last Modified: 10/5/2021
Location: FL, PR, USVI
Business: Part B
Q: We are receiving a denial with claim adjustment reason code (CARC) OA18. What steps can we take to avoid this denial code?
A: You will receive this reason code when more than one claim has been submitted for the same item or service(s) provided to the same beneficiary on the same date(s) of service.
• QA18 = Exact duplicate claim/service
The Medicare claims processing systems contain edits which identify exact duplicate claims and suspect duplicate claims submitted by physicians and practitioners. Please refer to preventing duplicate claim denials
for information on claim system edits regarding duplicate claims, and modifiers that may be used, as applicable, to identify repeat or distinct procedures and services on a claim.
Exact duplicate claims
• Claims or claim lines that exactly match another claim or claim line with respect to the following elements: Medicare ID, provider number, from date of service, through date of service, type of service, procedure code, place of service and billed amount
• Claims or claim lines are denied
• Appeal rights
Suspect duplicate claims
• Claims or claim lines that contain closely aligned elements sufficient to suggest that duplication may be present and, as such, require that the suspect claim be reviewed
• Criteria for identifying vary according to the following: type of billing entity, type of item or service being billed, and other relevant criteria
• Appeal rights (unless an exact duplicate)
• Ensure necessary appropriate modifiers are appended to claim lines, if applicable, and resubmit the claim.
• Append the applicable modifier(s) to the procedure code even if the diagnosis indicates the exact site of the procedure. For example: diagnosis code M1711 is a unilateral primary osteoarthritis, right knee or diagnosis code M1712 is a unilateral primary osteoarthritis, left knee. In this example, it would be appropriate to append modifier RT (right side) or LT (left side) to the procedure code(s) along with the related diagnosis code(s).
• Do not resubmit an entire claim when partial payment made; when appropriate, resubmit denied lines only.
• Do not refile a claim if the total approved amount has been applied to the patient’s deductible.
The following educational resources are available through First Coast University
and First Coast’s Medicare provider website:
• First Coast also offers free educational sessions throughout the year, focused on billing issues you may be experiencing. These may include webcasts or seminars on avoiding duplicate claims for Part B.
Visit the First Coast Medicare provider Events page
to learn about upcoming events and Learning on Demand Center
to link to encore presentations of webcasts conducted on this topic.
First Coast Service Options (First Coast) strives to ensure that the information available on our provider website is accurate, detailed, and current. Therefore, this is a dynamic site and its content changes daily. It is best to access the site to ensure you have the most current information rather than printing articles or forms that may become obsolete without notice.