The release of Transmittal 1422 states the following:
"The NCCI has Procedure to Procedure edits to prevent unbundling and consequent overpayment to physicians and outpatient facilities. The underlying principle is that the second code defines a subset of the work of the first code so it would be inappropriate to report it separately. Separate reporting would trigger a separate payment and would constitute double billing.
However it is recognized that in specific limited circumstances the duplicate payment could be sufficiently small or would not exist, so that separate payment would be indicated. Edits are defined by NCCI as optional and bypassable or as permanent and non-bypassable. Modifiers are used to bypass edits when they are set by NCCI as optional edits. The -59 modifier is both commonly used and commonly abused. According to the 2013 CERT Report data, a projected $2.4 Billion in MPFS payments were made on lines with modifier -59, with a $320 Million projected error rate. In facility payments, primarily OPPS, a projected $11 Billion was billed on lines with a -59 modifier with a projected error of $450 Million. This is a projected 1 year error of $770 Million.
NOTE: that this is not entirely due to incorrect -59 modifier usage as other errors can and do exist on a -59 line. However, it has been observed that incorrect modifier usage was a major contributor although error code definitions do not allow an exact breakdown. If 10% of the errors on -59 lines are attributable to incorrect -59 modifier usage, that still amounts to a $77 Million per year overpayment.
B. Policy:
CMS has defined four new HCPCS modifiers to selectively identify subsets of Distinct Procedural Services (-59 modifier) as follows:
• XE Separate Encounter, A Service That Is Distinct Because It Occurred During A Separate Encounter
• 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
These modifiers, collectively referred to as -X{EPSU} modifiers, define specific subsets of the -59 modifier. CMS will not stop recognizing the -59 modifier but notes that CPT instructions state that the -59 modifier should not be used when a more descriptive modifier is available. CMS will continue to recognize the -59 modifier in many instances but may selectively require a more specific - X{EPSU} modifier for billing certain codes at high risk for incorrect billing. For example, a particular NCCI PTP code pair may be identified as payable only with the -XE separate encounter modifier but not the -59 or other -X{EPSU} modifiers. The -X{EPSU} modifiers are more selective versions of the -59 modifier so it would be incorrect to include both modifiers on the same line." http://www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/Downloads/R1422OTN.pdf