Medically Unlikely Edits

The CMS developed Medically Unlikely Edits (MUEs) to reduce the paid claims error rate for Part B claims. An MUE for a HCPCS/CPT code is the maximum units of service that a provider would report under most circumstances for a single beneficiary on a single date of service. All HCPCS/CPT codes do not have an MUE.

Although CMS publishes most MUE values on its website, other MUE values are confidential and are for CMS and CMS Contractors' use only. The latter group of MUE values should not be released since CMS does not publish them.

There are three types of MUE tables available on the CMS Medically Unlikely Edits webpage. Practitioner, Durable Medical Equipment (DME) and Facility Outpatient. Part B MUEs are located in the Practitioner file. The table contains four columns:

  1. HCPCS/CPT Code: Contains code with MUE value.
  2. Practitioner Services MUE Values: Maximum units of service a practitioner would report under most circumstances for a beneficiary on a single date of service.
  3. MUE Adjudication Indicator (MAI): Describes the type of MUE (claim line or date of service).
    • MAI 1: Applied at line level (claim line) - Appropriate use of modifiers to report the same code on separate lines of a claim will enable the reporting of medically necessary units of service in excess of MUE
      • Modifier Examples: 76, 77, 91, RT, LT, F1, F2
    • MAI 2: Absolute criteria (date of service) – CMS has not identified any instances in which a higher value is payable
    • MAI 3: Value unlikely to appear on correctly coded claim but could, in unusual circumstances, be payable (date of service) – Exceptions rare, supporting documentation required
  4. MUE Rationale: Provides underlying basis

If the number of units is over the MUE value, all units are denied. These denials may be appealed with supporting documentation.


You may submit inquiries about the NCCI program, including those related to NCCI (PTP, MUE, and Add-on Code) edits, in writing via email to

Any submissions made to the NCCI program that contain Personally Identifiable Information (PII) or Protected Health Information (PHI) are automatically discarded, regardless of the content.

Inquiries about a specific claim or how to submit an appeal should be addressed to the Medicare Administrative Contractor (MAC).



Last Updated Apr 25 , 2023