What is modifier 59?
Modifier 59 (Distinct Procedural Service) indicates that two procedures or services performed on the same day were distinct and should not be bundled together. The 2025 CPT Manual offers the following clarifying information about modifier 59: “Under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-E/M services performed on the same day. Modifier 59 is used to identify procedures/services, other than E/M services, that are not normally reported together, but are appropriate under the circumstances.”
How does modifier 59 apply to otolaryngology-head and neck surgery procedures?
Plainly stated, modifier 59 is used to bill procedures performed on the same date of service that are not ordinarily encountered or performed on the same day by the same physician. Examples of such circumstances include:
- A different session or patient encounter
- A different procedure or surgery
- A different site or organ system
- A separate incision/excision or lesion
- A separate injury (or area of surgery in extensive injuries)
In otolaryngology-head and neck surgery, for example, a physician may perform a nasal endoscopy with biopsy of a nasal cavity lesion and, during the same encounter, excise a separate lesion on the external ear. Because the procedures involve different anatomical sites and are not typically performed together, modifier 59 may be appended to the appropriate CPT code to indicate that the services were distinct and separately reportable.
How should modifier 59 be appended in practice?
Due to high rates of misuse, modifier 59 is often heavily scrutinized by payers. It should only be appended when documentation clearly supports that the services were separate and non-overlapping. Modifier 59 should only be appended when there is no other more descriptive modifier available. Modifier 59 is generally appended to the lesser-valued service, but the designation of which code of a code-pair is assigned the modifier is defined by the National Correct Coding Initiative (NCCI) edits, available here.
When filing claims with the 59 modifier, be sure your documentation supports its usage as a separate and distinct procedure. Remember, modifier 59 is not intended to report procedures that require extra time or were performed to facilitate or provide access to a primary procedure that has already been done. If you’ve met all of the above requirements, modifier 59 can be used to differentiate services.
What are the X{EPSU} modifiers, and how do they relate to modifier 59?
In 2014, the Centers for Medicare and Medicaid Services (CMS) established four new HCPCS level II modifiers to provide greater reporting specificity for claims where modifier 59 would have previously been appended. These modifiers include XE, XS, XP, and XU, and they’re also referred to as the X{ESPU} modifiers.
- XE (Separate Encounter) – A service that is distinct because it occurred during a separate encounter on the same date of service
- XS (Separate Structure) – A service that is distinct because it was performed on a separate organ/structure
- XP (Separate Practitioner) – A service that is distinct because it was performed by a different practitioner
- XU (Unusual Non-Overlapping Service) – The use of a service that is distinct because it does not overlap usual components of the main service
Some payers, especially Medicare, prefer X{EPSU} modifiers as more specific alternatives to modifier 59 when appropriate. Always double-check your payers’ policies to determine if they’d prefer the use of X{ESPU} modifiers in place of modifier 59 to prevent inappropriate denials. For additional information on these modifiers, review the February 2025 Medicare Learning Network Article #1783722: Proper Use of Modifiers 59, XE, XP, XS & XU.
Can modifier 59 be appended to an E/M service?
No, modifier 59 should not be appended to an E/M service. For more information on reporting a separate and distinct E/M service with a non-E/M service performed on the same date, please reference the Academy’s CPT for ENT article on modifier 25.
Questions? Contact the Academy’s Health Policy team: [email protected].
Revised July 2026
Revised October 2023
Published July 2006
