MUE stands for “Medically Unlikely Edit” and refers to an edit for the units of service reported for a particular CPT/HCPCS code for the same beneficiary on the same date of service.
Introduced back in 2007, MUEs were implemented as an extension of the National Correct Coding Initiative (NCCI) to provide an additional safeguard in preventing improper payments based on incorrect units of service.
Where do I find a list of MUEs?
There are three separate MUE tables posted on the CMS website, which are updated and published on a quarterly basis:
Facility Outpatient Services
DME Supplier Services
It is important to note that the published tables are not an exhaustive list. In fact, some MUE values are confidential; therefore it is important to monitor claim denials for units of service carefully.
The MUEs tables can be downloaded at: http://www.cms.gov/Medicare/Coding/NationalCorrectCodInitEd/MUE.html
How are MUEs applied during claims adjudications?
An MUE is applied against each line item on a claim. The MUE value indicates the maximum number of units that can be billed per line. MUE edits can be bypassed by reporting procedures on separate lines of a claim with the appropriate NCCI modifier. Caution should be used when splitting a service into multiple line items.
What modifiers are used to bypass MUEs?
CPT modifiers such as -76 (repeat procedure by same physician), -77 (repeat procedure by another physician), anatomic modifiers (e.g., RT, LT, F1, F2), -91 (repeat clinical diagnostic laboratory test), and -59 (distinct procedural service) will accomplish this purpose. Modifier -59 should be utilized only if no other modifier describes the service.
CMS believes that the use of modifiers to bypass MUEs should be rare, and if providers find that this is a frequent occurrence, they should review their coding practices. The NCCI manual instructs providers to ask the following:
Is the HCPCS/CPT code being used correctly?
Is the unit of service being counted correctly?
Are all reported services medically reasonable and necessary?
Why does the provider’s or supplier’s practice differ from national patterns?
Note that there is a HCPCS modifier –GD that has an effective date of 1/1/2008:
GD - Units of service exceeds medically unlikely edit value and represents reasonable and necessary services (effective date 1/1/2008). Use this modifier to overwrite Medically Unlikely Edits (MUE) when appropriate. 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. MUE denials may be reported with ANSI Reason Code 151 and Remark code N362 on the Medicare EOB.
Although the modifier has an effective date of 1/1/2008, CMS has never issued instruction for use of this modifier for Medicare claims; therefore it should not be used at this time.
When is it appropriate to use NCCI modifiers to bypass an MUE?
Each case must be considered on an individual basis; however one instance for which modifiers are not permitted to bypass an MUE is radiological guidance for needle placement. Although CPT Assistant instructs to assign guidance codes per lesion, the NCCI manual Chapter 9 states the following:
“CPT codes 76942, 77002, 77003, 77012, and 77021 describe radiologic guidance for needle placement by different modalities. CMS payment policy allows one unit of service for any of these codes at a single patient encounter regardless of the number of needle placements performed. The unit of service for these codes is the patient encounter, not number of lesions, number of aspirations, number of biopsies, number of injections, or number of localizations.”
The NCCI manual is explicit in stating that these codes are to be reported only once per encounter, therefore it would not be appropriate to report multiple units by listing them as separate line items on claim.
It is important to always consult the NCCI Manual for additional information on limitations of units of service.
How can I request a reconsideration of an MUE?
A national healthcare organization, provider/supplier, or other interested third party may request a reconsideration of the MUE value of a HCPCS/CPT code by CMS by writing to Correct Coding Solutions, LLC.
Requests for modification of an MUE value should be sent to the following:
National Correct Coding Initiative
Correct Coding Solutions, LLC
P.O. Box 907
Carmel, IN 46082-0907
The requesting party should include its rationale and any supporting documentation. However, it is generally recommended that the party contact the national healthcare organization (medical specialty society) whose members perform the procedure prior to writing.
Can I have a Medicare beneficiary sign an ABN for services that may be denied because of an MUE?
MUEs are considered coding denials, not medical necessity denials, therefore an ABN cannot be issued to a Medicare beneficiary when a service exceeds an MUE value. An MUE denial is an initial determination based on a coding denial, not a medical necessity denial. By statute an ABN may be applied only if the initial determination on a claim results in a denial due to medical necessity. If a provider appeals an MUE denial and some units of service are denied as not medically necessary, the provider should NOT apply an ABN to bill the beneficiary. An appeal is not an initial determination, and by statute the ABN provision only applies to the initial determination.
Can I appeal an MUE denial?
Since claim lines are denied at Carriers and Part A/Part B Medicare Administrative Contractors (A/B MACs) processing claims with the MCS system, MUE-based claim line denials at these contractors may be appealed. Prior to April 2010, for FIs and A/B MACs processing claims with the Fiscal Intermediary Shared System (FISS), claims with a claim line with units of service exceeding an MUE value were returned to the provider, with no appeal available. However, since April 2010 these claims have been able to be appealed.
Reference: CMS FAQ’s Medically Unlikely Edits at http://www.cms.gov/Medicare/Coding/NationalCorrectCodInitEd/MUE.html