Last July, we covered updated guidance on X modifier use from the Centers for Medicare and Medicare Services (CMS). As WebPT’s Erica McDermott explains, “beginning July 1, 2019, CMS will unbundle NCCI edit pairs when providers attach the appropriate modifier (59, XE, XS, XP, or XU) to either the first-column or second-column code (assuming, of course, that the situation warrants the use of one of these modifiers).” While it’s still unclear what, exactly, this means for PTs, OTs, and SLPs who bill Medicare, one thing’s for certain: CMS will likely continue making these modifiers more accessible to providers across the healthcare spectrum—including rehab therapists. 

Furthermore, we’ve learned that some non-federal and commercial payers have started accepting X modifiers on rehab therapy claims. While X modifier use appears to be incidental (i.e., not the norm), we’ve received many inquiries from providers asking for guidance on the appropriate use of X modifiers. However, CMS, APTA, AOTA, and ASHA have remained pretty silent when it comes to additional details and example scenarios, which is why we strongly recommend contacting your payers first before applying any of these modifiers to your claims. That being said, we’ve put together the following therapy-specific examples based on our in-house experts’ best interpretation of the X modifier guidelines. 

XE (Separate Encounter)

Modifier XE indicates a service was distinct because it occurred during a separate encounter.

Example: A PT bills a single unit of group activity (97150) for three patients, then follows up with each patient one on one and bills two units of 97112.

Alternatively, a more obvious example would be a traumatic brain injury (TBI) patient in a day rehabilitation program where the PT bills for a service provided in the morning, then bills again for services provided in the afternoon.

XS (Separate Structure)

This modifier indicates a service was distinct because it was performed on a separate organ/structure.

Example: A PT bills two units of 97140, but he or she performed one unit of manual therapy on the cervical spine and one unit of manual therapy on the lower back. (Note that there is a lack of clarity as to how this would be applied, as the diagnosis codes would be different regardless.)

XP (Separate Practitioner)

This modifier indicates a service was distinct because it was performed by a different practitioner.

Example: A PT and an OT bill 97110 on the same day for a patient recovering from a stroke. The services are distinct because the providers are practicing under different disciplines. This assumes that the ICD-10 code is the same for both disciplines. As far as we can tell, we don’t believe it applies to situations where each provider is addressing a different diagnosis and thus, billing with a different ICD-10 code. 

XU (Unusual Non-Overlapping Service)

This modifier indicates a service was distinct because it didn’t overlap the usual components of the main service.

Example: A physical therapist provides mechanical cervical traction (97012) and manual therapy (97140) to a patient with a cervical condition. Because 97140 is typically a component of the more comprehensive code, 97012 and 97140 would need a modifier to justify billing both codes.


So, there you have it—a general overview of the X modifiers as they apply to rehab therapists. Again, it’s vital that providers check with each individual payer before applying an X modifier to the claim. But as the X modifier situation continues to develop, we’ll be sure to keep you informed and up to date.