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.
The first MUE edits were implemented January 1, 2007, with quarterly updates increasing the number of edits. Upon the implementation of the MUEs, CMS developed Change Request 5402 that required Medicare contractors to deny the claim line with units of service that exceed MUE criteria and pay the other services on the claim as part of initial claims processing activities. Beginning January 1, 2007, NHIC, Corp. allowed up to the MUE value and denied only the units in excess of the MUE value. It was recently brought to NHIC's attention that the CR specific instructions indicate contractors are to deny the entire claim line. Therefore, effective with a claim process date of May 11, 2009, NHIC will begin to deny the claim line with units of service that exceed MUE criteria.