Medically Unlikely Edits (MUEs)
While the majority of MUEs are publicly available on the CMS website, the Centers for Medicare & Medicaid Services will not publish all MUE values. MUEs that are published, are shown in tables on the CMS website.
MUE Tables change quarterly; the date of the change only affects claims with dates of service (DOS) on or after the new updated tables are issued. For example, if an MUE has an allowed amount of two on March 4, 2020, and the updated table shows an increase to five units as of April 1, 2020, the allowed for March 4, 2020, is still two. Any claims with date of service on or after April 1, 2020, would have an allowed amount of five.
Some MUEs allowed units are not published in the MUE table; this does not mean that there are no allowed units. It only means that CMS does not publish the allowable units for that code.
CMS MAI Indicators
The MUE Adjudication Indicator (MAI) indicates the type of MUE and its basis. The MAI assigned to HCPCS/CPT® codes will determine how your claim will process and/or deny.
The MAI types are listed in the charts below.
MAI of “1” or 51 MUE
- MUEs for HCPCS codes with a MAI of “1” will continue to be adjudicated as a claim line edit
- May require modifiers to distinguish:
- Repeat services
- Anatomic differences
MAI of “2” or 53 MUE
- MUEs for HCPCS codes with a MAI of “2” are absolute date of service edit
- Lines for same date of service are added together for the total number of units billed
- No need to split units to separate lines if appealing, the denial is for the total number of units billed
- These are “per day edits based on policy”
- Based on statue, description of HCPCS/CPT code, or coding guidance
- CMS gives no instances in which a higher value would be correct and payable
- Expectation is provider will not bill above allowable MUE
MAI of “3” or 54 MUE
- MUEs for HCPCS codes with a MAI of “3” are date of service edits
- These are “per day edits based on clinical benchmarks”
- Lines for same date of service are added together for the total number of units billed
- No need to split units to separate lines if appealing, the denial is for the total number of units billed
- Appealed additional units are considered if there is adequate documentation of medical necessity to support reported units
Correct Billing Examples
Biopsy services
- Line 1 = 11100 (MAI 2) Biopsy of single growth of skin and/or tissue — 1 unit
- Line 2 = 11101 (MAI 3) Biopsy of each additional growth of skin and/or tissue — each additional unit
Lab services
- Line 1 = 87070 (MAI 1) Bacterial culture — 3 units
- Line 2 = 87070 91 (MAI 1) Bacterial culture — 2 units
Surgical services
- Line 1 = 26111 (MAI 3) Excision, tumor or vascular malformation, soft tissue of hand or finger, subcutaneous; 1.5 cm or greater — 4 units
Important Points for Review
- If you report a code with units greater than the MUE value assigned, the line and/or claim will deny
- Be sure to carefully assess the description of a HCPCS/CPT code when billing a service, some important key words examples are noted below:
- Initial
- Subsequent
- Single level
- Second level
Many HCPCS/CPT® codes have common or similar terms, but there are differences in the description. Some examples include:
- Bilateral
- Unilateral
- Greater than
- Less than
- With
- Without
Some important reminders include:
- MUEs do not exist for all HCPCS/CPT® codes
- When appealing a MUE denial, records should clearly explain why the patient required more than the approved MUE for any service. A statement merely indicating that the patient required additional units, is not acceptable.
- Documentation submitted must support the units of service billed as reasonable and necessary
- Append the appropriate modifiers to ensure proper payment of the claim
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