CMS Pub. 100-04, ch. 23, § 20.9.3.2

All HCPCS/CPT codes with MUE values have an MAI.

MUEs for HCPCS/CPT codes with an MAI of “1”: MUEs for HCPCS/CPT codes with an MAI of “1” will

be adjudicated as a claim line edit.

MUEs for HCPCS/CPT codes with an MAI of “2”: MUEs for HCPCS/CPT codes with an MAI of “2” are

absolute date of service edits. These are “per day edits based on policy”. HCPCS/CPT codes with an MAI

of “2” have been rigorously reviewed and vetted within CMS and obtain this MAI designation because UOS

on the same date of service in excess of the MUE value would be considered contrary to statute, regulation,

or subregulatory guidance. Subregulatory guidance includes clear correct coding policy that is binding on

both providers or suppliers and the MACs. As stated in CR 8853, while Qualified Independent Contractors

(QICs) are not bound by subregulatory guidance, they should understand the policy nature of the MAI “2”

indicator when considering whether to pay UOS in excess of the MUE value if claim denials based on these

edits are appealed.

Limitations created by anatomical or coding restrictions are incorporated in correct coding policy, both in

the Health Insurance Portability & Accountability Act of 1996 (HIPAA) mandated coding descriptors and

CMS approved coding guidance as well as specific guidance in the CMS and NCCI Policy manuals. For

example, it would be contrary to correct coding policy to report more than 1 unit of service for "ventilation

assist and management . . . initial day" because such usage could not accurately describe 2 initial days of

management occurring on the same date of service as would be required by the code descriptor.

CMS establishes edits with an MAI of “2” based directly on regulation, statute or subregulatory guidance.

MUEs for HCPCS/CPT codes with an MAI of “3”: MUEs for HCPCS/CPT codes with an MAI of “3” are

date of service edits. These are “per day edits based on clinical benchmarks”. If claim denials based on these

edits are appealed, MACs may pay UOS in excess of the MUE value if there is adequate documentation of

medical necessity of correctly reported units. If MACs have pre-payment evidence (e.g. medical review) that

UOS in excess of the MUE value were actually provided, were correctly coded, and were medically

necessary, the MACs may bypass the MUE for a HCPCS/CPT code with an MAI of “3” during claim

processing, reopening, or redetermination, or in response to effectuation instructions from a reconsideration

or higher level appeal.

General Instructions on MUEs:

• MUEs are set high enough to allow for medically likely daily frequencies of services provided in most

settings. Because MUEs are based on current coding instructions and practices, MUEs are prospective

edits applicable to the time period for which the edit is effective. A change in an MUE is not retroactive

and has no bearing on prior services unless specifically updated with a retroactive effective date. In the

unusual case of a retroactive MUE change, MACs are not expected to identify claims but should reopen

impacted claims that providers or suppliers bring to their attention.

• Since MUEs are auto-deny edits, denials may be appealed. Appeals shall be submitted to the appropriate

MAC not the NCCI contractor. MACs adjudicating an appeal for a claim denial for a HCPCS/CPT code

with an MAI of “1” or “3” may pay correctly coded correctly counted medically necessary UOS in

excess of the MUE value.

• A denial of services due to an MUE is a coding denial, not a medical necessity denial. The presence of

an ABN shall not shift liability to the beneficiary for UOS denied based on an MUE. If during reopening

or redetermination medical records are provided with respect to an MUE denial for an edit with an MAI

of “3”, MACs will review the records to determine if the provider or supplier actually furnished units in

excess of the MUE, if the codes were used correctly, and whether the services were medically reasonable

and necessary. If the units were actually provided, but one of the other conditions is not met, a change in

denial reason may be warranted (for example, a change from the MUE denial based on incorrect coding

to a determination that the item/service is not reasonable and necessary under section 1862(a)(1)). This

may also be true for certain edits with an MAI of “1.” CMS interprets the notice delivery requirements

under Section 1879 of the Social Security Act (the Act) as applying to situations in which a provider or

supplier expects the initial claim determination to be a reasonable and necessary denial. Consistent with

NCCI program guidance, denials resulting from MUEs are not based on any of the statutory provisions

that give liability protection to beneficiaries under section 1879 of the Social Security Act. Thus, ABN

issuance based on an MUE is NOT appropriate. A provider or supplier may not issue an ABN in

connection with services denied due to an MUE and cannot bill the beneficiary for UOS denied based on

an MUE.

• If a procedure is performed bilaterally and the HCPCS/CPT code descriptor does not state that it is a

unilateral or bilateral procedure, report bilateral surgical procedures on a single claim line with modifier

50 and one (1) unit of service. For specific instructions for Ambulatory Surgical Centers, see the

Medicare Claims Processing Manual, Chapter 14, Section 40.5.

When modifier 50 is required by manual or coding instructions, claims submitted with 2 lines or 2 units

and anatomic modifiers will be denied for incorrect coding. MACs may reopen or allow resubmission of

those claims in accordance with their policies and with the policy in the Medicare Claims Processing

Manual, Chapter 34, Section 10.1.

Clerical errors (which include minor errors and omissions) may be treated as reopenings.

• Providers or suppliers may change and resubmit their own claims where possible but during reopening

MACs may, when necessary, correct the claim to modifier 50 from an equivalent 2 units of bilateral

anatomic modifiers. The original submitted version of the claim is retained in the Medicare IDR

(Integrated Data Repository).

• Providers or suppliers shall use anatomic modifiers (e.g., RT, LT, FA, F1-F9, TA, T1-T9, E1-E4) and

report procedures with differing modifiers on individual claim lines when appropriate. Many MUEs are

based on the assumption that correct modifiers are used.

• A/B MACs shall include with the review determination the more detailed explanation of the correct

coding initiative edit, which can be found in the standard correspondence language for A/B MACs in the

Medicare NCCI Correspondence Language Manual.

• MACs shall assign MSN 15.6. CARC 151 with Group Code CO for claims that fail the MUE edits,

when the UOS on the claim exceeds the MUE value, and deny the entire claim line(s) for the relevant

HCPCS/CPT code.

20.9.4 Reserved for future use

(Rev. 4465; Issued: 11-15-19, Effective: 01-30-19, Implementation: 01-30-19)

20.9.4.1 Reserved for future use

(Rev. 4465; Issued: 11-15-19, Effective: 01-30-19, Implementation: 01-30-19)