Distinct Procedural Service Includes 4 Modifiers

Modifier 59 is a modifier designated to identify services or procedures performed on the same day as a distinct procedural service due to special circumstances when these services or procedures are not normally reported together. Typically, modifier 59 is added to HCPCS/CPT codes when the billing claim form indicates two or more separate procedures are performed on separate body parts, organs or injured area, or different encounter on the same date of service by the same physician.

CMS uses four modifiers that take the place of modifier 59 in certain instances. According to CMS, modifier 59 is the most widely used modifier as well as the most incorrectly applied modifier. Modifier 59 has been the cause of provider audits, reviews, appeals, and fraud and abuse cases due to improper use.

Although CMS continues to acknowledge and accept the use of modifier 59, it added four additional subsets of modifier 59 effective January 1, 2015. These subsets provide a more specific or descriptive reason available to choose from:

  • XE Separate Encounter
  • XS Separate Structure
  • XP Separate Practitioner
  • XU Unusual Non-Overlapping Service

Modifier XE: Separate Encounter

Modifier XE: Separate Encounter

Definition: A service that is distinct because it occurred during a separate encounter.


Modifier XS: Separate Structure

Modifier XS: Separate Structure

Definition: a service that is distinct because it was performed on a separate organ/structure.


Modifier XP: Separate Practitioner

Modifier XP: Separate Practitioner

Definition: a service that is distinct because it was performed by a different practitioner.


Modifier XU: Unusual Non-Overlapping Service

Modifier XU: Unusual Non-Overlapping Service

Definition: the use of a service that is distinct because it does not overlap usual components of the main service.


Modifier 59: Distinct Procedural Service

Modifier 59: Distinct Procedural Service

Definition: Still acceptable except in instances in which a more specific modifier is available.

In addition, it would not be appropriate to use modifier 59 together with the other modifiers. Appropriate use of modifier 59 should be determined by referencing the NCCI procedure-to-procedure edit reference table.


NCCI Procedure-to-Procedure Edits

NCCI procedure-to-procedure edits prevent the reporting and payment of services that should not be billed on the claim together. NCCI edits can be found on four tables provided on the CMS website.

These tables are a reference for hospitals and physicians to identify sets of codes that cannot be submitted on the same claim or are mutually exclusive of one another. If the claim has both codes, there are two possibilities that can occur:

  1. Based on whether the code is listed ​on column 1 or column 2 of the table, the column 2 code will deny. Example: A provider should not report a unilateral diagnostic mammogram with a bilateral diagnostic mammogram. The unilateral diagnostic mammogram will not be eligible for payment.
  2. If the table indicates that there is a clinically appropriate modifier and the modifier is used, both columns will be eligible. Example: Use Modifier 59 with the secondary, additional or lesser procedure as listed on column 1 or column 2 as appropriate.
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