National Correct Coding Initiative (NCCI) Edits

The purpose of the Medicare National Correct Coding Initiative (NCCI) Edits is to prevent improper payment when incorrect code combinations are reported. CMS developed the coding policies based on coding principals defined in the American Medical Association's (AMA's) CPT Manual, through national and local policies and edits, and through coding guidelines developed by:

  • National societies
  • Analysis of standard medical and surgical practices
  • Review of current coding practices

These edits are prepay edits that are applied automatically to claims based on the specific coding listed on the claim. The NCCI contains one table of edits for physicians/practitioners, one table of edits for outpatient hospital services, and one table of edits for Durable Medical Equipment (DME) supplier services.

A subset of NCCI edits is incorporated into the outpatient code editor (OCE) for Outpatient Prospective Payment System (OPPS) and therapy providers, skilled nursing facilities (SNFs), comprehensive outpatient rehabilitation facilities (CORFs), outpatient physical therapies (OPTs) and speech-language pathology providers (SLPs), and home health agencies (HHAs) billing under TOBs 22X, 23X, 75X, 74X, 34X).

The CMS annually updates the NCCI Coding Policy Manual for Medicare Services. NCCI establishes and maintains the following edits.

If a provider has concerns about specific NCCI edits, he/she may submit comments in writing to:

National Correct Coding Initiative Contractor
Email: NCCIPTPMUE@cms.hhs.gov

Any submissions made to the NCCI program that contain Personally Identifiable Information (PII) or Protected Health Information (PHI) are automatically discarded, regardless of the content.

Inquiries about a specific claim or how to submit an appeal should be addressed to the Medicare Administrative Contractor (MAC).

Add-on Code Edits

An add-on code is a HCPCS/CPT code that describes a service that is always performed in conjunction with another primary service. An add-on code is eligible for payment only if it is reported with an appropriate primary procedure performed by the same practitioner. Add-on codes, with one exception, are never eligible for payment if it is the only procedure reported by a practitioner. The one exception is for the reporting of 99292 for critical care as this code does not require the reporting of 99291 for payment. CMS has divided the add-on codes into three groups to distinguish the payment policy for each group.

  • Type I - A Type I add-on code has a limited number of identifiable primary procedure codes. The Change Request (CR) lists the Type I add-on codes with their acceptable primary procedure codes. A Type I add-on code, with one exception, is eligible for payment if one of the listed primary procedure codes is also eligible for payment to the same practitioner for the same patient on the same date of service. Claims processing contractors must adopt edits to assure that Type I add-on codes are never paid unless a listed primary procedure code is also paid.
  • Type II - A Type II add-on code does not have a specific list of primary procedure codes. The CR lists the Type II add-on codes without any primary procedure codes. Claims processing contractors are encouraged to develop their own lists of primary procedure codes for this type of add-on codes. Like the Type I add-on codes, a Type II add-on code is eligible for payment if an acceptable primary procedure code as determined by the claims processing contractor is also eligible for payment to the same practitioner for the same patient on the same date of service.
  • Type III - A Type III add-on code has some, but not all, specific primary procedure codes identified in the CPT Manual. The CR lists the Type III add-on codes with the primary procedure codes that are specifically identifiable. However, claims processing contractors are advised that these lists are not exclusive and there are other acceptable primary procedure codes for add-on codes in this type. Claims processing contractors are encouraged to develop their own lists of additional primary procedure codes for this group of add-on codes. Like the Type I add-on codes, a Type III add-on code is eligible for payment if an acceptable primary procedure code as determined by the claims processing contractor is also eligible for payment to the same practitioner for the same patient on the same date of service.

CMS updates the Add-on Code edits on a quarterly basis to add, delete and make revisions to the three add-on code categories.

Medically Unlikely Edits (MUEs)

MUEs were created by CMS to establish edits based on units of service for specific codes to reduce inappropriate payments and the edits are updated on a quarterly basis. The edits apply to the Medicare Part B benefit, such as, outpatient services billed on the UB-04 claim form. The MUE edits are prepay edits that automatically apply to the claim when the code billed represents units in excess of the maximum MUE value. The maximum amount of units for the service have been determined as the maximum that would typically occur under most circumstances for the code reported, for a single beneficiary, on a single date of service. When an outpatient claim is processed, the submitted procedures are analyzed to determine if they comply with the MUE policy. When an MUE is billed in excess of the maximum value the claim or line will be medically denied at the claim level or line level and require an appeal be submitted for review of the service(s).

CMS has not created MUEs for all HCPCS/CPT codes. They apply only to the services specifically listed in the MUE tables. Again, NCCI updates the MUEs quarterly, which could mean additional HCPCS are added to the list or that the number of units have changed for certain codes. The unit changes could be an increase or a decrease in the number of services allowed for the code. CMS does post a majority of the MUE unit values for codes with a maximum value of one, two or three units. CMS has indicated they will not publish all MUE values of four or higher due to concerns of potential fraud and abuse. It is important to only report the number of services that were reasonable and necessary as medical reviews could be done if it appears as though MUEs are being abused.

Before NCCI implements new or changes an existing MUEs, NCCI submits the proposed edits for review and comments to the:

  • AMA
  • National medical and surgical societies
  • Other national healthcare organizations including:
    • Non-physician professional societies
    • Hospital organizations
    • Laboratory organizations
    • DME organizations

MUEs are developed based on the reasonable practice for procedures and coding guidelines. CMS also takes into consideration anatomic probabilities, medical policies, clinical judgments and finally the framework or the nature of the service/procedure.

The MUE files on the NCCI website display "MUE Adjudication Indicators" (MAIs) for each HCPCS/CPT code. An MAI of "1" indicates the edit is a claim line level MUE. When a HCPCS/CPT code has an MUE MAI of "1" or is a claim line edit, appropriate CPT modifiers may be used to report the same HCPCS/CPT code on a separate line or lines of a claim. Each line of the claim with that HCPCS/CPT code will be separately adjudicated against the MUE value for that HCPCS/CPT code. Examples of appropriate modifiers may be:

  • 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 (valid only for Outpatient Prospective Payment System (OPPS) providers)
  • 59 - Distinct procedural service or X-modifiers
  • Modifier 59 or X-modifiers should be used only if no other modifier describes service. See more in CMS Change Request (CR) 8863

An MAI of 2 or 3 indicates the edit is a date of service MUE. MAIs of ‘2' are absolute per day date of service edits, which are based on policy. The MAI of ‘2' edits have been rigorously reviewed and vetted within CMS. Codes that obtained the MAI of ‘2' designation received this because units of service on the same date of service in excess of the MUE value would be considered impossible as it is contrary to statute, regulation or subregulatory guidance. The subregulatory guidance includes clear correct coding policy that is binding on both providers and CMS claims processing contractors. E.g. It would not be appropriate to report more than one unit of service for CPT 94002, ventilation assist and management initial day. More than one usage could not accurately describe two initial days of management occurring on the same date of service based on the code descriptor. As a result, Noridian has been instructed that an MAI of ‘2' has claim processing restriction without override capabilities Codes with a MAI of ‘2' will automatically deny an initial claim submission, reopening, or redetermination.

MAIs of ‘3' are per day edits based on clinical benchmarks. MAIs of ‘3' are based on criteria, e.g. nature of service or prescribing information, which is combined with data to indicate it is possible but highly medically unlikely that higher values would represent correctly reported medically necessary services. When Noridian has evidence through medical review that units of service in excess of the MUE value were actually provided, were correctly coded and were medically necessary, the editing will bypassed during claim processing, reopening or redetermination.

Billing Units in Excess of MUE

Providers must determine the correct MUE value and MAI for the specific HCPCS/CPT code if the value and MAI are listed on the CMS MUE webpage. Units billed in excess of the MUE value for HCPCS/CPT codes with a MAI are ‘2' or ‘3' will automatically deny with or without an appropriate modifier.

When the MAI is ‘1', providers must bill one line with the revenue code, HCPCS/CPT code, date of service, no modifier and the correct number of units for the MUE value. The second and/or subsequent line(s) must be billed with the units up to the MUE value but not exceeding the MUE value with the correct modifier. Providers may also bill one unit per line with the appropriate modifier on all lines accept the first line. Examples of appropriate modifiers may be:

  • 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 (valid only for Outpatient Prospective Payment System (OPPS) providers)
  • 59 - Distinct procedural service or X-modifiers
    • Modifier 59 or X-modifiers should be utilized only if no other modifier describes the service. See more at CR 8863

The Medicare system will not allow payment when more than double of the MUE limit is represented on one line. E.g., Provider rendered a five units of service for a HCPCS/CPT code with an MAI of ‘1' with a MUE value of three.

  • Line 1 - Report revenue code, HCPCS/CPT code, date of service and three units
  • Line 2 - Report revenue code, HCPCS/CPT code, appropriate modifier, date of service, and two units

Procedure to Procedure Edits (PTP)

The purpose of the NCCI PTP edits is to prevent improper payment when incorrect code combinations are reported and has been incorporated into the outpatient code editor (OCE). The NCCI contains one table of edits for physicians/practitioners and one table of edits for outpatient hospital services. The Column One/Column Two Correct Coding Edits table and the Mutually Exclusive Edits table have been combined into one table and include PTP code pairs. The tables contain pairs of HCPCS/CPT codes that should not typically be reported together. The tables include the PTP modifier indicators which indicate if a modifier is allowed on the column two code.

  • Modifier indicator "0" - modifier is not allowed
  • Modifier indicator "1" - modifier is allowed
  • Modifier indicator "9" - modifier is not applicable

Each edit has a column one and column two HCPCS/CPT code. When both codes in column one and column two are reported, the column one code is eligible for payment. When the column two code has a modifier indicator of "1", the code is eligible for payment if the appropriate modifier is appended. When the column two code has a modifier indicator of "0" or "9" the column two code is not eligible for payment.

There are times the column two code is a component of a more comprehensive column one code. Many times the code pair edit simply represents two codes that should not be reported together. E.g., Providers should not report a vaginal hysterectomy code and total abdominal hysterectomy code together and the modifier indicator for the example is "0", not allowed. CMS updates the PTP edits on a quarterly basis to add, delete and make revisions to the code combinations.

Questions/Concerns

You may submit inquiries about the NCCI program, including those related to NCCI (PTP, MUE, and Add-on Code) edits, in writing via email to NCCIPTPMUE@cms.hhs.gov.

Any submissions made to the NCCI program that contain Personally Identifiable Information (PII) or Protected Health Information (PHI) are automatically discarded, regardless of the content.

Inquiries about a specific claim or how to submit an appeal should be addressed to the Medicare Administrative Contractor (MAC).

Resources

Last Updated Jan 29 , 2024