Modifier 59 is Getting a Makeover in 2015

Starting 2015, Medicare’s most popular modifier is getting a makeover done. The CMS has introduced four new Healthcare Common Procedure Coding System (HCPCS) modifiers to define subsets of the -59 modifier, which is used to designate a “distinct procedural service.” As modifier 59 is being used in a wide variety of circumstances, for instance to identify: different encounters; different anatomic sites; and distinct services; it is often misused incorrectly to bypass National Correct Coding Initiative (NCCI) edits. This has lead to high levels of manual audit activity, and civil fraud and abuse cases.


To keep a check on that, CMS has divided the Modifier 59 into 4 new HCPCS subset modifiers:

  • XE – Separate Encounter to code a distinct service that occurred during a separate encounter;
  • XS – Separate Structure to code a distinct service performed on a separate organ or structure;
  • XP – Separate Practitioner to code a distinct service performed by a different practitioner;
  • XU – Unusual Non-Overlapping Service to code for a distinct service that does not overlap with the usual components of the main service.


However, CMS will continue to accept Modifier -59 or one of the more selective modifiers “although the rapid migration of providers to the more selective modifiers is encouraged.” In the recently issued MLN Matters article, CMS instructs providers to continue to use the -59 modifier if there is uncertainty on the use of the new X modifiers. CMS states that “Additional guidance and education as to the appropriate use of the new –X(EPSU) modifiers will be forthcoming as CMS continues to introduce the modifiers in a gradual and controlled fashion. That guidance will include additional descriptive information about the new modifiers. CMS will identify situations in which a specific –X(EPSU) modifier will be required and will publish specific guidance before implementing edits or audits.”


The lack of clarity regarding the use of the new modifiers resulted in many doubts. Here are few tips to cope up with the challenges:

  • Ask your vendor to load the new modifiers in their system
  • Educate and learn about National Correct Coding Initiatives edits
  • Facilities and providers, watch out for further updates from CMS and their interpretation of the -X (EPSU) modifiers
  • Check the CMS Manual System One Time Notification for more information on the new modifiers to replace Modifier 59


Also, if you are uncertain about the changing picture of modifier 59, check out the latest Audio Conferences on Modifier 59 from industry veterans at

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