Preventing duplicate claim denials - with example

Providers are responsible for all claims submitted to Medicare under their provider number. Preventable duplicate claims are counterproductive and costly, and continued submission to Medicare may lead to program integrity action.

Please share this information with your billing companies, vendors and clearing houses: Claim system edits search for duplicate, suspect duplicate and repeat services, procedures and items within paid, finalized, pending and same claim details in history. Duplicate claims and claim lines are automatically denied. Suspect duplicate claims and claim lines are suspended and reviewed by the Medicare administrative contractor (MAC) to make a determination to pay or deny. Click here for additional information.

Medicare correct coding rules include the appropriate use of condition codes and/or modifiers. When you submit a claim for multiple instances of a service, procedure or item, the claim should include an appropriate modifier to indicate that the service, procedure or item is not a duplicate. Note that the modifier should be added to the second through subsequent line items for the repeat service, procedure or item. (An example is listed below.) In many instances, this will allow the claim to process and pay, if applicable.

However, in some instances, even if an appropriate modifier is included, the claim may deny as a duplicate, based on medically unlikely edits (MUEs). MUEs are maximum units of service that are typically reported for a service, medical procedure or item, under most instances, for a beneficiary on a single date of service. Note that these duplicate denials may not always be considered preventable.


Review your billing procedures and software, and use appropriate modifiers, as applicable. The following are examples of modifiers that may be used on your claim to identify that the service, procedure or item is not a duplicate. Please review the Current Procedural Terminology (CPT®) codebook for a complete list of modifiers.

• Modifier 59: Service or procedure by the same provider, distinct or independent from other services, performed on the same day. Services or procedures that are normally reported together but are appropriate to be billed separately under certain circumstances.

• The Centers for Medicare & Medicaid Services (CMS) established four new modifiers, effective January 1, 2015, to define subsets of modifier 59. Refer to MLN Matters® article MM8863 external pdf file for details.
• Modifier 76: Repeat service or procedure by the same provider, subsequent to the original service or procedure.
• Modifier 91: Repeat clinical diagnostic laboratory tests. This modifier is added only when additional test results are medically necessary on the same day.

• Example: Laboratory submits Medicare claim for four glucose; blood, reagent strip tests (CPT® code 82948).
Line 1: 82948
Line 2: 82948 and modifier 91
Line 3: 82948 and modifier 91
Line 4: 82948 and modifier 91

• Modifiers RT (right side) and LT (left side): Append applicable modifier to the procedure code, even if the diagnosis indicates the exact site of the procedure.

• Example: Provider submits Medicare claim for diagnosis code M1711 (unilateral primary osteoarthritis, right knee) and/or diagnosis code M1712 (unilateral primary osteoarthritis, left knee). Modifier RT should be added to the procedure code billed with diagnosis code M1711. Modifier LT should be added to the procedure code billed with diagnosis code M1712.