RESOLVED: Incorrect Coinsurance Percentage Applied for Drugs and Biologicals

Published 04/11/2022

RESOLVED: Incorrect Coinsurance Percentage Applied for Drugs and Biologicals

Current Status



Resolved 4/11/2022 Adjustments have been completed.



The MCS system maintainer installed a fix on February 4, 2022, and Palmetto GBA verified claims are now pricing correctly. The system maintainer will provide MACs with a list of affected claims.



Since the system maintainer’s installed fix, Palmetto GBA has identified drug claims still being sporadically affected by the initial issue. The sporadic issue could apply to any dates of service processed between November 15 and November 22, 2021. Palmetto GBA has reported this to the system maintainer for research. This issue will be updated when new information is available. There is no provider action required.



The MCS system maintainer has clarified that some drug claims finalized between 10/26/2021 and 10/29/2021 may have had an incorrect coinsurance amount applied (.02 percent instead of 20 percent). 

The MCS System maintainer installed a fix after the claims processing cycles that finalizes claims on 10/29/2021 and is currently researching to identify all claims impacted by the issue and will alert MACs once they have completed their research.



The MCS system maintainer is currently researching this issue and will notify MACs when additional details regarding a system fix and corrective actions are available. Providers may sign up for this CPIL’s “Article Update Notification” to receive email updates on this issue.

Provider Action


There is no provider action needed or any need to contact the provider contact center regarding this issue.




The MCS system maintainer has notified Medicare Administrative Contractors (MACs) of an issue where the copayment amount applied to drug and biological claims for any date of service finalized on or after October 27, 2021, may have been applied at .02 percent instead of 20 percent. (11/12/2021: Issue verbiage updated to reflect the percentage of coinsurance incorrectly applied.) 

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