CMS is establishing four new HCPCS modifiers to define subsets of the -59 modifier, a modifier used to define a “Distinct Procedural Service.”

The use of modifiers is an integral part of coding and billing, and due to the increased coding and billing guidelines, it is important for physicians and billing staff to be up to date. Inaccurate or inappropriate use of modifier -59 can and has generated overpayments, incorrect coding and increased audits. CMS has established four new HCPCS modifiers to define subsets of the -59 modifier, a modifier used to define a “Distinct Procedural Service.” The modifier -59 has been a go-to modifier and is widely used by providers to indicate a second procedure code that is actually distinctly different or separate from the first procedure code.
CMS has indicated that it won’t stop recognizing modifier -59, but the new-X modifiers, define specific subsets of modifier -59.
The new HCPCS modifiers, referred to collectively as -X modifiers, are defined as:

• 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; and
• XU Unusual Non-Overlapping Service, The Use Of A Service That Is Distinct Because It Does Not Overlap Usual Components Of The Main Service

http://www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/Downloads/R1422OTN.pdf