NCCI Medically Unlikely Edits (MUEs)
MUEs are maximum units of service that a single provider would reasonably report on a single date for a single beneficiary, with three adjudication levels (line, date, claim).
Primary source
CMS NCCI Medically Unlikely Edits →https://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits/medicare-ncci-medically-unlikely-edits
Verified May 23, 2026 · This is the authoritative regulator URL. The summary below is a research aid; the linked source controls.
Medically Unlikely Edits (MUEs) are the maximum units of service that a provider would typically report on a single date of service for a single beneficiary for a particular HCPCS/CPT code. Units of service exceeding the MUE are denied or returned for review.
MUE Adjudication Indicators (MAI):
- MAI 1 (Line Edit): units above the MUE on a single line are denied; units may be split across multiple lines using appropriate modifiers when clinically justified.
- MAI 2 (Date of Service Edit — absolute): units above the MUE on the date of service cannot be billed — these reflect statutory limits or anatomic impossibility.
- MAI 3 (Date of Service Edit — overrideable): units above the MUE on the date of service are denied but can be appealed with documentation.
MUE values for most codes are publicly published; some are flagged as confidential by CMS. Practices billing high-volume procedures should know the MAI for their key codes — an MAI 2 with units above the threshold is not appealable, only correctable.
Like PTP edits, MUE values are updated quarterly. The MUE file and policy guidance are published on the CMS NCCI hub.
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Related across the archive
- RegulationNCCI Modifier Overrides (Modifier 59 and X{EPSU})Modifier 59 (and its more specific subsets XE, XS, XP, XU) is the principal mechanism for overriding a PTP edit when a procedure is distinct or independent from another performed on the same day.
- RegulationNCCI Policy Manual OverviewThe National Correct Coding Initiative is the CMS coding edits program that prevents improper Medicare payment due to incorrect code reporting; the Policy Manual is the authoritative coding-policy reference.
- RegulationNCCI Procedure-to-Procedure (PTP) EditsPTP edits identify code pairs that should not be reported together because one is a component of the other or because reporting both is otherwise inconsistent with correct coding.
- GlossaryMUE (Medically Unlikely Edits)CMS-set maximum units of service that a provider would report under most circumstances for a single beneficiary on a single date of service.
- GlossaryNCCI EditsThe CMS National Correct Coding Initiative edits that prevent improper payment when incorrect code combinations are reported.
- RegulationModifier 25: Significant, Separately Identifiable E/M ServiceModifier 25 is appended to an E/M code when the E/M is significant and separately identifiable from another procedure or service performed on the same day by the same provider.
- RegulationNCCI Bilateral Procedure Reporting RulesMedicare's policy for reporting bilateral procedures uses the MPFS Bilateral Indicator (0, 1, 2, 3, 9) and depends on whether the code descriptor already includes both sides.
- RegulationNCCI Chapter 11: Evaluation and Management ServicesNCCI policy on bundling and separately reporting E/M services with procedures, including modifier 25 use and global surgical package interactions.
Last reviewed May 23, 2026 · Citation verified May 23, 2026
Research aid, not legal advice. This summary is an administrative research aid prepared by D3rx. It does not certify compliance, provide legal advice, replace counsel, or guarantee an audit outcome. For authoritative regulatory text follow the primary source link at the top of this page. The practice remains responsible for reviewing, adopting, and maintaining its compliance program.