Physical therapists (PTs), take note: the 59 modifier is a potential red flag for the US Centers for Medicare and Medicaid Services (CMS) and commercial payers.

The 59 modifier is the code under the health care common procedural code system (HCPCS) used to represent a service that is separate and distinct from another service it's paired with. In an effort to tease out precisely why the service is distinct, CMS is requiring that in certain cases, providers use different modifiers instead of the 59 modifier. The modifiers—XE, XP, XS, and XU—are intended to bypass a National Correct Coding Initiative edit by denoting a distinct encounter, anatomical structure, practitioner, or unusual service.

When the X modifiers were introduced in 2015, PTs weren't required to use them. But movement toward the use of these modifiers—and greater scrutiny of claims using the 59 modifier—is happening.

CMS recently issued detailed guidance on the use of the 59 and X modifiers, complete with examples of what it considers appropriate and inappropriate applications. Providers should carefully review the CMS guidance document, as well as check their commercial payer payment policies regarding the use of the 59 modifier versus the X modifiers.

APTA will continue to monitor this issue and share news of any changes.