CurrentOptumPolicy N/A

Maximum Frequency Determination (MFD) for units billed

Governs reimbursement limits for the number of units billed per CPT/HCPCS code on a single date of service for Optum-administered Commercial, Medicare, and Individual Exchange plans and applies to all providers submitting CMS 1500 or electronic 837p claims.

Policy Summary

PayerOptum

PolicyMaximum Frequency Determination (MFD) for units billed

Policy CodePolicy N/A

Change TypeNo material change

Effective DateN/A

Next Review DateN/A

Key ActionWhen units exceed the MFD, report them with an appropriate modifier (59, XE, XS, XU) to be considered for additional reimbursement.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

MAI 2 = no overridesMAI 2 restriction

New = 100New code default

Unlisted = 999Unlisted code default

Per-day = 1Per-day limit

59, XE, XS, XUAccepted modifiers

Maximum Frequency Determination (MFD) Reimbursement Rules

MFD reimbursement criteria

Reimbursement rules for billed units relative to Maximum Frequency Determination (MFD) values.

Services are reimbursable up to and including the MFD value for each CPT/HCPCS code.

MFD values are determined in the following hierarchy: use the CMS MUE value where available; if the code description indicates reporting once per day, MFD = 1; if the code description specifies a frequency, set MFD to that value; when no other value is established, unlisted CPT/HCPCS codes default to MFD = 999 (bypass); new CPT/HCPCS codes default to MFD = 100 until CMS MUE or claims data are available.

Modifier pathway for units > MFD

When reported units exceed the established MFD, additional reimbursement may be considered if an appropriate modifier is appended (examples: 59, XE, XS, XU).

Policy Summary

PayerOptum

PolicyMaximum Frequency Determination (MFD) for units billed

Policy CodePolicy N/A

Change TypeNo material change

Effective DateN/A

Next Review DateN/A

Key ActionWhen units exceed the MFD, report them with an appropriate modifier (59, XE, XS, XU) to be considered for additional reimbursement.

SourceLink

On This Page

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Code-Specific MFD Determination and Special Handling

Special code handlingmixed

unlisted	Unlisted CPT/HCPCS codes default to MFD value of 999 (bypass policy)
new	New CPT/HCPCS codes default to MFD value of 100 until CMS MUE or claims data available

MFD determination hierarchy

Primary precedenceUse the CMS Medically Unlikely Edit (MUE) value where available to establish the MFD value (including unlisted codes)

Descriptor frequencyIf the CPT/HCPCS code description references reporting the code once per day, set MFD = 1

Descriptor-specified frequencyIf the code description indicates the number of times the service can be performed, set MFD to that specified value

Unlisted codes defaultUnlisted CPT/HCPCS codes default to MFD = 999 (bypass the MFD policy)

New codes defaultNew CPT/HCPCS codes without other definitive criteria default to MFD = 100 until CMS MUE or claims data are available

Per-day code threshold

Per-day language ruleCodes whose descriptor includes 'per diem', 'per day', or similar once-daily verbiage are limited to MFD = 1

Question & answer confirmationOptum will allow 1 unit for a procedure code with 'per diem' or 'per day' or other once-daily verbiage in the code description

ApplicationThis MFD = 1 rule applies regardless of other billing lines; multiple lines reporting the same code may still be classified as duplicates

Billing Modifiers and Override Guidance

Billing Rule

Modifier use for units exceeding MFD

When reporting units that exceed the Maximum Fee Determination (MFD) for an individual CPT or HCPCS code, report the additional units with an appropriate modifier to request reimbursement above the MFD. Acceptable modifiers for this purpose include modifier 59 and the XE/XS/XU subset modifiers. Medical records do not need to be submitted with the claim when modifier 59, XE, or XU is appropriately reported; however, documentation in the medical record must reflect and support the number of units billed and the clinical rationale for the modifier.

Affected modifiers: 59, XE, XS, XU
Medical record must document number of units and support modifier use
No claim-attached records required when 59/XE/XU are properly reported

Denial Risk

MAI 2 override prohibition

CPT/HCPCS codes assigned a Medically Unlikely Edit (MAI) indicator of '2' are designated by CMS as codes for which units in excess of the MFD (MUE) are impossible and cannot be paid. Optum will not allow reimbursement for units reported in excess of the MFD for MAI '2' codes, and no modifier override (including 59, XE, XS, XU) will be permitted.

MAI indicator '2' = no overrides allowed
Excess units for MAI '2' codes will not be reimbursed

Key Terms and Definitions

Definition of 'units'

Units definitionThe number of times services with the same CPT or HCPCS code are provided per day by the same individual physician or other qualified health care professional

Same individual defined'Same individual' is defined as the same individual rendering services reporting the same Federal Tax Identification number

Claim-line implicationApplies whether units are submitted as multiple units on one claim line or as separate claim lines; duplicate lines may be classified as duplicate service

Definition of MFD

MFD definitionThe highest number of units eligible for reimbursement for a service on a single date of service

Determination sourcesMFD is determined by CMS MUE where available, otherwise by code descriptor frequency or established policy defaults

Policy purposeMFD values are set to prevent overpayment from billing submission and data entry errors while enabling reimbursement of properly reported services

Definition of MAI 2

MAI 2 meaningA CMS adjudication indicator where units beyond the MUE are considered impossible (contrary to statute, regulation, or guidance)

Reimbursement impactFor CPT/HCPCS codes assigned MAI indicator '2', units in excess of the MFD will not be reimbursed

Override prohibitionPer CMS guidelines, no modifier override will be allowed for codes assigned MAI '2'