Understanding MUE Usage Denials and Bilateral Procedures Using MUEs
MUEs are used by Medicare to help reduce improper payments for Part B claims. This article will address the use of the National Correct Coding Initiative (NCCI) and Medically Unlikely Edits (MUEs) and how they are used by CMS. MUEs are applied to Healthcare Common Procedure Coding System (HCPCS) and Current Procedural Terminology (CPT) codes to indicate the maximum number of units commonly used on a single date of service.
CMS assigns Medically Unlikely Edits (MUEs) for HCPCS/CPT to most codes. However, not every code has an MUE assigned. According to CMS, MUE edits are used to limit tests and treatments provided to a Medicare patient for a single date of service or for a single line item on a claim form. It is important to understand that MUEs are not to be used as utilization guidelines; CMS is concerned that providers will incorrectly interpret MUE values as utilization guidelines. MUE values do NOT represent units of service that may be reported without concern about medical review. Providers should continue only to report services that are medically reasonable and necessary.
According to CMS, although CMS publishes most MUE values on its website, other MUE values are confidential. Confidential MUE values are not releasable.
Find-A-Code lists the MUE values that have been released by CMS; these MUEs can be found on the CPT code information page under the additional information for easy access.
| Reminder: MUEs are used on a case-by-case basis and are not to be used as utilization guidelines. In other words, if your clinical data reflects the need for additional units and it is medically reasonable and necessary, it should be reported. |
Reasons for MUE Rationale
- Published Contractor Policy
- CMS Policy
- Clinical: Data
- Nature of Equipment
Bilateral Procedures and MUEs
You may be wondering how MUEs work with bi-lateral procedures, good question. We first need to understand Medicare's correct coding instructions; we are required to report a bilateral procedure with a 50 Modifier and one Unit of Service (UOS) on the same line. To understand if a procedure can be performed bilaterally, pay careful attention to the following.
The code description: Always start here; the code may state in the description if the procedure is bilateral, for example, 27395- Lengthening of hamstring tendon: multiple tendons, bilateral.
Bilateral Indicator: Medicare uses what is called Medicare Physician Fee Schedule (MPFS) indicators; one indicator is called a Bilateral Surgery Indicator, letting us know whether special payment rules apply, such as the 150% payment rule for a bilateral procedure. The bilateral surgery indicator lets us know if modifier 50 is allowed to be reported with the procedure/CPT code. Let's take a look at the same CPT code, 27395- Lengthening of hamstring tendon: multiple tendons, bilateral. CMS has assigned a bilateral Surgery indicator of "2," indicating the 150% payment adjustment for bilateral surgery does NOT apply. Therefore, you cannot code this procedure with Modifier 50, as the code already includes a bilateral procedure in the description.
| Bilateral Indicator | Description |
| 0 | No bilateral payment adjustment: (a) because of physiology or anatomy, or (b) because the code description specifically states that it is a unilateral procedure, and there is an existing code for the bilateral procedure. |
| 1 | 150% Bilateral payment adjustment applies: If the code is billed with the bilateral modifier or is reported twice on the same day by any other means (e.g., with RT and LT modifiers or with a 2 in the units field), base the payment for these codes when reported as bilateral procedures on the lower of (a) the total actual charge for both sides or (b) 150% of the fee schedule amount for a single code. If the code is reported as a bilateral procedure and is reported with other procedure codes on the same day, apply the bilateral adjustment before applying any multiple procedure rules. |
| 2 | Bilateral procedure 150% payment adjustment does not apply. RVUs are already based on the procedure being performed as a bilateral procedure. If the procedure is reported with modifier -50 or is reported twice on the same day by any other means (e.g., with RT and LT modifiers or with a 2 in the units field), base the payment for both sides on the lower of (a) the total actual charge by the physician for both sides, or (b) 100% of the fee schedule for a single code. Example: The fee schedule amount for code YYYYY is $125. The physician reports code YYYYY-LT with an actual charge of $100 and YYYYY-RT with an actual charge of $100. Payment should be based on the fee schedule amount ($125) since it is lower than the total actual charges for the left and right sides ($200). The RVUs are based on a bilateral procedure because (a) the code descriptor specifically states that the procedure is bilateral, (b) the code descriptor states that the procedure may be performed either unilaterally or bilaterally, or (c) the procedure is usually performed as a bilateral procedure. |
| 3 | No bilateral payment adjustment. The usual payment adjustment for bilateral procedures does not apply. If the procedure is reported with modifier -50 or is reported for both sides on the same day by any other means (e.g., with RT and LT modifiers or with a 2 in the units field), base the payment for each side or organ or site of a paired organ on the lower of (a) the actual charge for each side or (b) 100% of the fee schedule amount for each side. If the procedure is reported as a bilateral procedure and with other procedure codes on the same day, determine the fee schedule amount for a bilateral procedure before applying any multiple procedure rules. Services in this category are generally radiology procedures or other diagnostic tests which are not subject to the special payment rules for other bilateral surgeries. |
For additional details, see "Examples of Correct Coding for Bilateral Procedures, see MLN SE142."
What are the MAI indicators?
Each MUE is assigned a Medicare Adjudication Indicator (MAI), further specifying how MACS look at MUEs. MUEs and MAIs are used by providers, suppliers, and MACS in all settings. These are the most common and published MAIs. There are MUEs with a value of less than 1 and a value of 4 or more that are not published due to concerns from CMS about fraud and abuse.
MAI 1 - adjudicated as a claim line edit
MAI 2 - per day edits based on policy (Impossible to bill excess MUEs)
MAI 3 - per day edits based on clinical benchmarks (UOS in excess of the MUE value were actually provided, were correctly coded, and were medically necessary)
MUEs are automatically denied or deemed an "auto-deny edit." |
Because they are auto-deny edits, it is important to be aware of the MAIs assigned to each MUE. These denials should all be appealed and returned for reconsideration if denied incorrectly. ASC Providers (specialty Code 49) cannot use modifier 50 (Bilateral procedure); therefore, the MUE with an MAI of 1 is automatically doubled by the MAC.
Incorrect usage of MUEs will be denied as a coding denial, not a clinical or medically necessary denial.
Claim Remark Codes
On your EOB or remittance advice, to identify claims that fail the MUE edit claim, remark codes N362 and MA01 will be used.
Durable Medical MUEs
CMS also assigns MUEs to Durable Medical supplies and equipment. Notice the difference in the examples below; you can see if we look at the description first, A4218 is only for 10 ML of saline or water, and A4238 is for a 1-month supply. Therefore, the allowable MUEs make sense.
| HCPCS code | Description | MUE Value |
| A4218 | Sterile saline or water, metered dose dispenser, 10 ml | 56 |
| A4238 | Supply allowance for adjunctive, non-implanted continuous glucose monitor (cgm), includes all supplies and accessories, 1 month supply = 1 unit of service | 1 |
Questions
For questions on a specific claim, you will need to contact your MAC representitave. If your questions are about the MUE program or questions related to NCCI (PTP, MUE, and Add-On) edits, send them to NCCIPTPMUE@cms.hhs.gov.
Appeals and Reconsideration
According to HHS If a national healthcare organization, provider, or other party wants to submit a request for reconsideration of an MUE value, the procedure described in the Frequently Asked Questions (FAQs) should be followed. See the web link below. Such requests should be addressed to:
National Correct Coding Initiative
Email: NCCIPTPMUE@cms.hhs.gov
