MUE's Explained

What You Need to Know

Medically Unlikely Edits are designed to lower the percentage of claims that Medicare pays in error. Specifically, every L code describing a bracing or prosthetic device has a numerical MUE assigned to it. The number represents the maximum units of service for that code that can be provided by the same supplier for the same beneficiary on the same date of service.

A claim with units of service for a code that are in excess of the MUE value will result in Medicare denying that code. So, for example, if you submit a claim for patient Jane Smith on June 9th, 2026 that includes more than two units of service for L1843 or L5981 - both of which have a MUE of 2 - those codes will get denied.

There are, however, limited instances in which you can get payments for units of service in excess of the MUE number. Medicare's MUE file includes a column titled "MUE Adjudication Indicator." Any L code that has a MAI beginning with the number 3 is potentially eligible for payment in excess of the MUE limit; you must document in your clinical notes the medical necessity justifying providing more than the standard number of items.

You cannot issue an Advanced Beneficiary Notice for services denied due to an MUE, nor can you bill the beneficiary for units of service denied based on an MUE.

What This Means for You

First, check the number of units carefully before billing. If it exceeds the MUE for a given L code, the excess units will be denied automatically, regardless of medical necessity. These denials are predictable and preventable.

Second, do not assume you can appeal or override the edit. Most MUE denials cannot be overturned through standard appeals, nor can you use an ABN to shift liability to the patient.

Lastly, know when exceptions are possible. For codes with an MAI that begins with the number 3, you may be able to successfully appeal the initial denial, but only when you have clear, specific documentation of medical necessity to support the overage.

MUEs are a front-end claims issue. By understanding the limits and validating units before submission, you can significantly reduce avoidable denials and protect revenue.

CMS updates the MUE list on a quarterly basis. You can access the Q2 2026 MUE's file here.