Reason Code 51MUE

Published 12/16/2019

Beginning with dates of service on and after 01/01/07, it has been determined the units of service are in excess of the medically reasonable daily allowable frequency for HCPCS with a MAI of 1. The excess charges due to units of service greater than the maximum allowable may not be billed to the beneficiary and; this provision can neither be waived nor subject to an advanced beneficiary notification (ABN). Note: this reason code is assigned effective for claims received on or after 04/01/2010. This reason code is bypassed when a 55 CPT modifier is present.

Units at line level are billed in excess for allowable units based on National Correct Coding Initiative (NCCI) edits for Medically Unlikely Edits (MUE). If units of service can be justified, a Redetermination may be submitted. Redetermination should include:

  • All applicable supporting medical documentation
  • Corrected UB-04 form

If the excessive units were submitted in error, a Redetermination may be submitted.

Note: Redeterminations will only review medically denied lines.

CMS National Correct Coding Initiative Edits — Although CMS publishes most MUE values on its website, other MUE values are confidential and are for CMS and CMS Contractors' use only.

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