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Medicare NCCI Medically Unlikely Edits (MUEs) — quarterly change files posted December 1, 2025, effective January 1, 2026 (Practitioner Services, Outpatient Hospital Services, DME Supplier Services).
CMS Posts 2026 Q1 Medicare MUE Updates: What to Change Before January 1 Claims
If your systems still enforce 2025 Q4 MUE caps, a subset of January 2026 claims can deny automatically for exceeding updated units-of-service limits—even when the underlying service was legitimate.
Last updated: December 18, 2025
For practice owners, billing managers, compliance leads, RPM/RTM operators, and revenue cycle teams billing Medicare Part B.
How to use this page
This is an operational compliance guide, not legal advice. Use it to update unit-limit logic in claim scrubbers and billing workflows against CMS’s published Medicare NCCI MUE quarterly files and change reports.
Who this affects
- Recurring, high-volume billing patterns (RPM, RTM, CCM, APCM, repeat labs, supply spans)
- Professional claims (Medicare Part B practitioner), outpatient hospital claims, and DME supplier claims
- Teams with software or staff that can load too many units onto a single date of service
Thesis
Update your unit-of-service limits now. Claim scrubbers and billing workflows that still enforce 2025 Q4 values will trigger denials the moment January 2026 claims hit MAC adjudication.
Section Index / Navigation Map
- Key takeaway in one sentence
- What CMS posted for January 1, 2026
- What an MUE is and how it is adjudicated
- Common failure patterns that trigger denials
- Why these patterns fail in audits and appeals
- Edge cases and clarifications (MAI, modifiers, appeals, retroactive changes)
- Practical implications for RPM/RTM/CCM/APCM operations
- Planning checklist
- How this fits the broader CMS trajectory
- How FairPath enforces MUE compliance
- FAQ
- References
Key Takeaway in One Sentence
Beginning January 1, 2026, Medicare claim lines that exceed the updated NCCI MUE units-of-service caps for the applicable MUE table (Practitioner, Outpatient Hospital, or DME Supplier) are subject to automated denials, so claim scrubbers and billing workflows must be updated to the CMS-posted Q1 2026 MUE files and adjudication indicators before January submissions.
What CMS Posted for January 1, 2026
On December 1, 2025, CMS published the Q1 2026 quarterly change files (additions, deletions, revisions) for all three MUE tables, effective January 1, 2026:
- DME Supplier Services
- Outpatient Hospital Services
- Practitioner Services
CMS also publishes full tables and keeps only the current and prior quarter publicly visible, so internal version retention is operationally important.
What an MUE Is and How It Is Adjudicated
Definition
Medicare’s National Correct Coding Initiative (NCCI) includes Medically Unlikely Edits (MUEs): automated unit-of-service ceilings to prevent improper payment when a CPT/HCPCS code is billed with an implausible quantity. An MUE is the maximum units reported for the same provider/supplier, same beneficiary, same date of service on the vast majority of appropriately reported claims. Not all codes have MUEs, and some values are confidential.
Tables by Context
CMS maintains separate tables for practitioner, outpatient hospital, and DME supplier services. The same code can have different behavior depending on the claim stream, so scrubbers must evaluate the correct table.
Claim-Line vs Date-of-Service
- Claim-line MUEs (MAI 1): each claim line is compared to the MUE. If units on that line exceed the MUE, all units on that line are denied. Multiple lines with appropriate modifiers can adjudicate independently.
- Date-of-service MUEs (MAI 2 or 3): all units for the same code, provider/supplier, beneficiary, date of service are summed across claim lines (regardless of modifiers). If the sum exceeds the MUE, all units for that code on the claim are denied.
MAI Implications
CMS uses an MUE Adjudication Indicator (MAI) to signal behavior:
- MAI 2: policy-based, absolute date-of-service edit.
- MAI 3: date-of-service edit with limited appeal paths when correctly coded and medically necessary.
Common Failure Patterns That Trigger Denials
- Treating MUE compliance as an annual update rather than quarterly.
- Validating claims against the wrong table (e.g., using practitioner limits for facility claims or vice versa).
- Assuming monthly services lack day-level limits, then posting multiple units to a single date when catching up or truing up monthly time.
- Splitting lines with modifiers to bypass a date-of-service MUE; the system sums units across lines for MAI 2/3.
- Treating an MUE denial like a medical-necessity denial and routing to patient-liability workflows.
- Issuing ABNs for anticipated MUE denials; CMS explicitly states ABNs do not shift liability for MUEs.
Why These Patterns Fail in Audits and Appeals
- Claims processing logic is deterministic. CMS describes exactly how claim-line and date-of-service MUEs adjudicate, including summing across lines for MAI 2/3.
- CMS directs consistent denial coding: CARC 151 (CO) applies when units exceed the MUE value and the entire relevant claim line(s) are denied.
- Liability shifting is not available. CMS rejects ABN-based liability shifting for MUE denials and characterizes them as coding denials.
Edge Cases and Clarifications
Retroactivity
CMS positions MUEs as prospective edits; retroactive changes are unusual and must be explicitly dated. MACs are not expected to proactively identify retroactive claims but may address cases brought to their attention.
Appeals Above the Cap
MUE denials may be appealed to the MAC. For MAI 1 or 3, MACs may pay units above the MUE in some circumstances when correctly coded, counted, and medically necessary. MAI 2 operates as an absolute policy-based edit.
Replacement Files
CMS sometimes issues mid-quarter replacement files to correct edit values. Operations need both quarterly updates and a lightweight path to ingest replacements.
Public vs Confidential Values
Some MUEs are confidential and may change status. Absence of a published value is not proof that no MUE exists.
Remit Behavior
CMS instructs contractors to use CARC 151 (Group Code CO) when units exceed the MUE and to deny the entire claim line(s) for the relevant code.
Practical Implications for RPM/RTM/CCM/APCM Operations
RPM/RTM/CCM/APCM environments combine high recurring volume, frequent catch-up workflows, and billing abstraction layers that translate operational time into claim lines. When systems post multiple units onto one date to represent monthly totals or staff consolidate units for convenience, date-of-service MUEs can be violated even when clinical work occurred.
Because missing a quarterly MUE update can introduce denials across an entire patient panel on day one of the quarter, MUE compliance is a stability requirement for recurring revenue, not a coding trivia item.
Planning Checklist
- Download the Q1 2026 MUE quarterly change files (additions/deletions/revisions) for Practitioner, Outpatient Hospital, and DME Supplier Services posted December 1, 2025.
- Refresh the full MUE tables and record the effective date/version in your compliance log; retain copies because CMS posts only current and prior quarters.
- Update scrubber logic to evaluate the correct MUE table for the claim stream (professional vs facility vs DME).
- Ensure scrubbers apply MAI behavior: claim-line vs date-of-service adjudication; avoid “split lines with modifiers” unless MAI supports it.
- Monitor MUE denials using CARC 151 (CO) and route to coding/unit correction workflows, not patient billing.
- Train staff that ABNs do not shift liability for MUE denials.
- Implement an alert path for CMS mid-quarter replacement files so updates are not limited to quarterly cadence.
How This Fits the Broader CMS Trajectory
MUEs exemplify CMS’s shift toward front-end, automated program integrity. By encoding unit plausibility, code-pair logic, and modifier rules directly into claims processing systems through the NCCI framework, CMS limits improper payment before it happens. Remote care and care-management programs that are recurring and software-mediated are especially exposed because standardized edits now operate as policy enforced in code.
How FairPath Enforces MUE Compliance
FairPath treats MUE compliance as versioned policy:
- Quarterly MUE files and change reports are ingested as effective-dated rulesets aligned to CMS posting/effective dates, segmented by claim context.
- Claim construction checks MUE limits using MAI logic, so the platform does not attempt modifier workarounds where date-of-service summation makes them invalid.
- Denial intelligence routes CARC 151 patterns into coding/unit remediation consistent with CMS’s characterization of MUE denials as coding denials.
- Patient-liability workflows are blocked for MUE denials because CMS explicitly disallows ABN-based shifting for MUE denials.
FAQ
Yes. CMS’s Medicare NCCI MUE page lists Q1 2026 MUE quarterly additions/deletions/revisions ZIPs for DME Supplier, Outpatient Hospital, and Practitioner Services posted December 1, 2025, effective January 1, 2026.
At least quarterly. CMS sometimes issues replacement files mid-quarter to correct specific values.
Whether the code’s MAI indicates claim-line (MAI 1) or date-of-service (MAI 2/3) adjudication. That determines whether splitting lines with modifiers can ever matter.
CMS instructs contractors to use CARC 151 (Group Code CO) when units exceed the MUE value and to deny the entire relevant claim line(s).
No. CMS states an MUE denial is a coding denial. ABN issuance based on an MUE is not appropriate, and providers or suppliers may not bill the beneficiary for units denied due to an MUE.
Sometimes. CMS states MUE denials may be appealed to the MAC. For MAI 1 or MAI 3, MACs may pay units above the MUE in some circumstances when correctly coded, correctly counted, and medically necessary. MAI 2 is positioned as an absolute policy-based edit.
References
Primary CMS sources
- CMS Medicare NCCI Medically Unlikely Edits (MUEs) page (Q1 2026 postings, effective date, change files).
- CMS Medicare NCCI FAQ Library (definitions, adjudication logic, MAI meaning, update cadence, confidentiality).
- Medicare Claims Processing Manual, Pub. 100-04, Chapter 23, Section 20.9 (MUE definition/context; ABN prohibition; CARC 151 instruction; appeal notes; retroactivity notes).
- MLN: How to Use the Medicare NCCI Tools (MAI definitions; ABN guidance).
- MLN Matters MM8853 and related CMS transmittals (MUE program modifications; ABN guidance).
Standards / remittance coding references
- X12 Claim Adjustment Reason Codes (CARC 151 definition).
