X Modifiers

XE

Separate encounter, a service that is distinct because it occurred during a separate encounter

XP

Separate practitioner, a service that is distinct because it was performed by a different practitioner

XS

Separate structure, a service that is distinct because it was performed on a separate organ/structure

XU

Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service