Bundling & NCCI
Intelligence Center

The National Correct Coding Initiative (NCCI) is a CMS program that identifies procedure code combinations that should not be billed together. NCCI edits prevent improper payment for services that are bundled, mutually exclusive, or incidental.

NCCI includes two types of edits: Procedure-to-Procedure (PTP) edits and Medically Unlikely Edits (MUEs). PTP edits identify code pairs that should not be reported together. MUEs identify the maximum units of a service that a single provider would report for a single beneficiary on a single date of service.

PTP edits have a modifier indicator: 0 = cannot be overridden by a modifier; 1 = can be overridden with an appropriate modifier (e.g., 59, XE, XS, XP, XU) when the services are distinct and separate.

NCCI edits are updated quarterly (January, April, July, October). Always check the current version of the NCCI tables for the date of service being billed.

NCCI PTP edits apply to Medicare claims. Commercial payers may adopt NCCI edits or have their own bundling rules. Always verify the payer's specific bundling policy.

Bundling is the practice of combining multiple procedure codes into a single, more comprehensive code for payment. CMS and payers bundle services that are considered integral to a primary procedure.

When a code is bundled into another code, it is not separately payable. The payment for the bundled service is included in the payment for the primary procedure.

Example: CPT 93000 (ECG, complete) is bundled into CPT 93005 (ECG, tracing only) when reported together. The tracing is considered integral to the complete ECG.

Bundling prevents "unbundling" — the practice of billing separate codes for services that should be reported as a single comprehensive code. Unbundling is considered fraudulent billing.

NCCI PTP edits are the primary source of bundling rules for Medicare. Commercial payers may have their own bundling logic, often based on NCCI but with payer-specific modifications.

Unbundling is the improper practice of billing separate procedure codes for services that should be reported as a single comprehensive code. Unbundling inflates reimbursement and is considered fraudulent billing.

Example: Billing CPT 11042 (debridement, subcutaneous tissue) and CPT 97597 (debridement, open wound) for the same wound on the same date. These services are bundled because debridement of the same wound should be reported with a single code.

NCCI PTP edits with a modifier indicator of 0 cannot be unbundled — the services are always bundled, and no modifier can override the edit.

NCCI PTP edits with a modifier indicator of 1 can be "unbundled" (overridden) with an appropriate modifier (e.g., 59, XE, XS, XP, XU) when the services are truly distinct and separate. The modifier must be supported by documentation.

Improper unbundling — using a modifier to override a bundling edit when the services are not truly separate — is a common cause of denials, audits, and overpayment recoupments.

Mutually exclusive procedures are procedure code pairs that cannot reasonably be performed together because they are contradictory, overlap, or describe the same service in different ways.

Example: CPT 58150 (total abdominal hysterectomy) and CPT 58180 (supracervical hysterectomy) — these are mutually exclusive because a hysterectomy cannot be both total and supracervical.

NCCI identifies mutually exclusive procedure pairs and assigns them a modifier indicator. Most mutually exclusive edits have a modifier indicator of 0 (cannot be overridden).

If a modifier indicator is 1, the edit can be overridden when the procedures are performed on separate organs or anatomical sites, or in separate sessions, and the documentation supports the distinct services.

Mutually exclusive edits are a subset of NCCI PTP edits. They are identified in the NCCI tables by the edit rationale column.

Incidental procedures are procedures that are considered an integral part of a more comprehensive procedure and are not separately payable. The service is "incidental" to the primary procedure.

Example: CPT 49000 (exploratory laparotomy) is considered incidental to CPT 58150 (total abdominal hysterectomy) when performed through the same incision. The exploration is included in the hysterectomy.

Incidental procedures are identified in NCCI PTP edits and in the CPT code guidelines. The CPT code book may note that a procedure is "included in" or "integral to" another procedure.

Incidental procedures cannot be unbundled with a modifier — they are always bundled into the primary procedure. NCCI assigns a modifier indicator of 0 for incidental procedure edits.

For commercial payers, incidental procedures may be identified in the payer's medical policy or coding guidelines. Always check the payer's specific policy.

The Global Surgical Package includes all services that are included in the payment for a surgical procedure. It covers the pre-operative, intra-operative, and post-operative services provided by the surgeon.

The global period for most major surgical procedures is 90 days. For minor procedures, the global period is 0 or 10 days. The global period is specified in the Medicare Physician Fee Schedule (MPFS) for each CPT code.

Services included in the global surgical package: pre-operative visits after the decision for surgery, the surgical procedure itself, all post-operative visits (routine follow-up), and complications management that do not require a return to the operating room.

Services NOT included in the global package: the initial consultation or evaluation that led to the decision for surgery, services for unrelated problems, and services that require a return to the operating room.

Modifier 24 (unrelated E/M during a post-operative period) and Modifier 25 (significant, separately identifiable E/M on the same day as a procedure) are used to report E/M services that are not included in the global package.

Modifier 57 (decision for surgery) is used when the E/M service results in the decision for surgery and occurs on the day before or the day of the surgery (for procedures with a 90-day global period).

Modifier 59 (Distinct Procedural Service) is used to indicate that a procedure or service was distinct or independent from other services performed on the same day. It overrides NCCI PTP edits that have a modifier indicator of 1.

Modifier 59 should be used only when no other modifier more accurately describes the distinct service. CMS introduced the X{EPSU} modifiers (XE, XS, XP, XU) as more specific alternatives to Modifier 59.

Modifier 59 is appropriate when: the procedures are performed at different anatomic sites, different encounters/sessions, by different providers, or for different reasons (e.g., a therapeutic procedure and a diagnostic procedure on the same day).

Modifier 59 should NOT be used when: the procedures are performed at the same anatomic site in the same session, the procedures are routine components of a comprehensive service, or the NCCI edit has a modifier indicator of 0.

Documentation must support the distinct nature of the services. Include the anatomic site, session/encounter, provider, and reason for each service.

Overuse of Modifier 59 is a common audit target. Use the more specific X{EPSU} modifiers when they more accurately describe the situation.

Modifier XE (Separate Encounter) is used to indicate that a service was performed in a separate encounter on the same date. It is a more specific alternative to Modifier 59 for the "separate encounter" scenario.

XE is appropriate when the same or similar service is performed at a different time on the same day, in a distinct clinical encounter. Example: an E/M service in the morning and a procedure in the afternoon, each for distinct clinical reasons.

XE should NOT be used when the services are part of the same encounter or session. If the services are in the same encounter, use a different modifier or do not use a modifier at all.

Documentation must show the time of each service and the distinct clinical reason for each encounter. Include the start and stop times if available.

XE is one of the four X{EPSU} modifiers introduced by CMS in 2015 as more specific alternatives to Modifier 59. Use XE when the "separate encounter" scenario applies.

Modifier XS (Separate Structure) is used to indicate that a service was performed on a separate organ/structure. It is a more specific alternative to Modifier 59 for the "separate anatomic site" scenario.

XS is appropriate when the same procedure is performed on a different organ or structure. Example: debridement of a wound on the left leg and debridement of a separate wound on the right leg.

XS should NOT be used when the procedures are on the same organ or structure, or when the procedures are on the same anatomic site. Use a different modifier or no modifier.

Documentation must specify the anatomic site for each procedure. Include the laterality (left/right), the specific organ or structure, and the distinct nature of each service.

XS is one of the four X{EPSU} modifiers. Use XS when the "separate structure" scenario applies.

Modifier XP (Separate Practitioner) is used to indicate that a service was performed by a separate practitioner. It is a more specific alternative to Modifier 59 for the "separate provider" scenario.

XP is appropriate when the same procedure is performed by a different provider in the same group or a different group. Example: a dermatologist performs a biopsy and a surgeon performs an excision on the same day.

XP should NOT be used when the procedures are performed by the same provider. Use a different modifier or no modifier.

Documentation must identify the provider for each procedure. Include the provider name, NPI, and the distinct clinical reason for each service.

XP is one of the four X{EPSU} modifiers. Use XP when the "separate practitioner" scenario applies.

Modifier XU (Unusual Non-Overlapping Service) is used to indicate that a service was performed for an unusual reason that does not overlap with other services. It is a more specific alternative to Modifier 59 for the "unusual, non-overlapping service" scenario.

XU is appropriate when the service is distinct because it is for a different reason or diagnosis than the other services. Example: a diagnostic procedure and a therapeutic procedure for different diagnoses on the same day.

XU should NOT be used when the services overlap or are for the same reason. Use a different modifier or no modifier.

Documentation must show the distinct diagnosis or reason for each service. Include the ICD-10 diagnosis code and the clinical rationale for each service.

XU is one of the four X{EPSU} modifiers. Use XU when the "unusual, non-overlapping service" scenario applies.

The CPT code book designates some procedures as "Separate Procedure" in the code descriptor or parenthetical notes. This designation means the procedure is normally not reported separately when performed as part of a more comprehensive procedure.

When a "Separate Procedure" code is performed as an integral part of a more comprehensive procedure, it is bundled and not separately payable. Example: CPT 49000 (exploratory laparotomy) is a Separate Procedure and is bundled into CPT 58150 (total abdominal hysterectomy).

A "Separate Procedure" code CAN be reported separately when it is performed: (1) independently of, and not immediately related to, another procedure, or (2) at a separate anatomic site or in a separate session.

When reporting a "Separate Procedure" code separately, use Modifier 59 (or the appropriate X{EPSU} modifier) to indicate the distinct service. Documentation must support the separate nature of the service.

The "Separate Procedure" designation is defined in the CPT code book, not in NCCI. However, NCCI PTP edits often reflect the "Separate Procedure" designation.

CO-97 (bundling) — the procedure is bundled into another procedure and is not separately payable. Fix: verify the NCCI PTP edit. If the services are truly distinct, append the appropriate modifier (59, XE, XS, XP, XU). If not, remove the bundled code.

CO-50 (not medically necessary) — the procedure is not deemed medically necessary when performed with another procedure. Fix: appeal with documentation of medical necessity for each procedure.

CO-11 (diagnosis inconsistent) — the diagnosis does not support the procedure or the combination of procedures. Fix: correct the diagnosis code to support the procedure.

CO-24 (not a covered benefit) — the payer does not cover the combination of procedures. Fix: verify the payer's coverage and bundling policy.

CO-16 (missing or invalid modifier) — a modifier was required to override the NCCI edit but was not present or was invalid. Fix: append the correct modifier (59, XE, XS, XP, XU) with supporting documentation.

CO-151 (payment adjusted) — the payment was adjusted because the procedure was bundled or reduced. Fix: verify the NCCI edit and the modifier. If the services are distinct, appeal with documentation.