The Medicare KX modifier threshold for CY2026 is $2,480 combined for physical therapy and speech-language pathology. Occupational therapy has a separate threshold of $2,480.
When a beneficiary’s outpatient therapy expenses exceed this threshold in a calendar year, the KX modifier is required on claims to indicate that the services are medically necessary and that the provider has documentation to support continued treatment.
What the KX modifier means
The KX modifier is a claim-line modifier that tells Medicare: “This beneficiary has exceeded the threshold, and I, the treating provider, certify that the services are medically necessary and that a valid plan of care exists.”
Using the KX modifier is not optional above the threshold — claims without it for services over the threshold will deny. It’s also not a blank check: CMS can request the clinical documentation to support the modifier, and if the documentation doesn’t hold up, overpayment recovery follows.
What triggers the threshold
The threshold is calculated based on Medicare allowed amounts, not charges. Only Part B outpatient therapy services count toward the threshold. Inpatient, home health, and SNF services do not.
Therapy in the following settings counts toward the threshold:
- Physician/NPP offices
- Outpatient hospital departments
- Independent therapy practices
- CORF (Comprehensive Outpatient Rehabilitation Facilities)
Documentation requirements
When you apply the KX modifier, you are certifying that:
- There is a valid, signed plan of care that supports continued therapy
- The services are medically necessary (not maintenance-level)
- The functional limitations and the expected benefit are documented in the medical record
⚠️ Risk flag: “Maintenance therapy” does not support the KX modifier. If a patient has reached their maximum rehabilitative benefit and therapy is maintaining their current functional level, services may still be covered — but under the Jimmo v. Sebelius maintenance therapy standard, not the KX modifier exception. These are different documentation requirements.
What changed from CY2025
The threshold increased from $2,230 (CY2025) to $2,480 (CY2026). Documentation requirements are unchanged. The threshold is adjusted annually based on the Medicare Economic Index.
Ask Mae if you have questions about applying the KX modifier in a specific clinical situation.