Medically Unlikely Edits and Related Billing Clarifications
An MUE is the maximum number of UOS allowable under most circumstances for a single HCPCS/CPT code billed by a provider for a particular date of service for a single beneficiary.
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Prior to Billing
Match documentation to CPT/HCPCS codes. Ensure exactly what the CPT/HCPCS code descriptor states and whether it includes any qualifying term such as “bilateral” or right/left or whether a different code actually describes some or all of the services performed.
General Billing Guidelines When an MUE Is Involved
- Report the CPT/HCPCS code subject to an MUE edit on one line of the claim up to the MUE allowed when documented and medically reasonable and necessary
- Number of units reflect less than or equal to the number of units allowed per MUE
- No modifier is required
- When additional units of the same CPT/HCPCS were rendered and medically necessary, bill those additional units on a separate claim line
- Ensure an appropriate modifier is billed
- Ensure only one additional line is billed for the additional services; billing multiple lines for each additional unit of service may result in a denial as a duplicate
- The total number of units billed for the specific CPT/HCPCS code should match the medical records documentation
Be aware of the correct billing when a code has an MUE limit:
- CPT/HCPCS code with an MUE assigned and MAI (MUE adjudication indicator) is 1 is edited as a claim line edit
- CPT/HCPCS code with an MUE assigned and MAI is 2 is edited as an absolute DOS (per day) edit. If appropriate, bill according to billing instructions provided for an MAI of 1. Typically, UOS on the same DOS in excess of the MUE value would be considered impossible because it was contrary to statute, regulation or sub-regulatory guidance. Thus, there is most likely a different code that is used for additional services.
- Example:
- One unit of CPT code 11043 (Debridement, muscle and/or fascia [includes epidermis, dermis and subcutaneous tissue, if performed]; first 20 square cm or less) is allowed per date of service.
- Additional units would be appropriately billed using the applicable add-on code. For example: the second line would reflect another code that reflects the service performed – such as CPT code 11046 (each additional 20 sq. cm. list separately in addition to code for primary procedure) with the units reflecting the additional units performed per documentation
- Example:
- CPT/HCPCS code with an MUE assigned and MAI is 3 is edited as date of service edits/“per day edits based on clinical benchmarks”.
- Example:
- 1 unit of CPT code 27403 (Arthrotomy with meniscus repair, knee) is allowed per date of service
- In this scenario, the documentation shows that this procedure was actually preformed bilaterally; thus. It is billed as 27403 with a modifier 50 to show it was performed bilaterally
- Denials for MUE with MAI of 3:
- Providers should carefully assess any denials based on these edits and consider the denial to be an indication of incorrect reporting due to such things as clerical errors or errors in the interpretation or application of coding instructions. It is also possible some errors are associated with a lack of medical necessity for the excess units. Note that the MUE itself does not address medical necessity. The MUE only addresses the medically unlikely nature of the reported value.
In the rare instance where the provider has verified all information, including the correct interpretation of coding instructions, and still believes that the correctly coded medically necessary service exceeds the MUE, the provider should submit a clearly supported appeal.
- Providers should carefully assess any denials based on these edits and consider the denial to be an indication of incorrect reporting due to such things as clerical errors or errors in the interpretation or application of coding instructions. It is also possible some errors are associated with a lack of medical necessity for the excess units. Note that the MUE itself does not address medical necessity. The MUE only addresses the medically unlikely nature of the reported value.
- Example:
Note: The above codes are used as examples only in this document – please refer to the current CPT/HCPCS manual and MUE edits for the most current information.
In response to questions as to whether to report the actual number of units provided versus rolling up the units:
- When HCPCS/CPT codes are required to bill for services provided, the units are equal to the number of times the procedure/service being reported was performed according to the HCPCS/CPT code description. The National Correct Coding Initiative Policy Manual for Medicare Services specifies units of service and must be billed correctly. This manual can be found on CMS's National Correct Coding Initiative Edits website.
In response to questions on whether to bill services as covered or noncovered, we offer the following:
- Providers are obligated to code correctly whether or not an edit exists. In addition, the general rules for billing noncovered services always applies; thus, if the provider believes that the service is not covered then it should be billed as noncovered. Conversely, if the provider believes the service should be covered, then bill such services as covered.
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Reviewed 10/11/2023