The Center for Medicare & Medicaid Services (CMS) developed the National Correct Coding Initiative (NCCI) program for Medicare services billed by a single physician for a single patient on the same date of service. They include three types of edits: NCCI Procedure-to-Procedure (PTP) edits, Medically Unlikely Edits (MUEs), and Add-on Code (AOC) Edits. Commercial payers may or may not follow published NCCI edits and create their own, verify each unique policy.

Procedure-to-Procedure Edits

PTP edits prevent improper payment of services that should not be reported together. PTP edits can include:

• Mutually exclusive codes — Codes with an indicator of “0” can never be paid separately.
• Comprehensive codes —Bundled codes with an indicator of “1” may be paid separately when the definition of modifier -59 has been met
• Error codes — Codes with an indicator of “9” have been bundled in error and should be resubmitted for payment

Medically Unlikely Edits

MUEs prevent payment for an inappropriate number/quantity of the same service on a single day. The assigned MUE indicates the maximum units of service reported for a HCPCS/CPT code that can be billed by the same physician/supplier for the same beneficiary on the same date of service.

Add-on Code Edits

An AOC is a HCPCS or CPT code that describes a service performed with another primary service by the same physician. An AOC is not eligible for payment when billed by itself.

CMS implements edit revisions quarterly. A link to CMS’s NCCI webpage can be found at aao.org/coding-topics