Managing the KX Threshold: Keeping Medicare Patients in Care Past the $2,480 Cap
The Medicare therapy threshold is one of the most misunderstood rules in outpatient PT billing. Many practices treat the KX modifier as a simple checkbox. It is not. Appending KX is an attestation—a declaration that medically necessary care exceeds the dollar threshold—and it comes with documentation obligations that RAC auditors actively review.
Here is what you need to know for 2026.
The 2026 Threshold: $2,480
For calendar year 2026, the Medicare outpatient therapy threshold is $2,480 for physical therapy and speech-language pathology services combined. Occupational therapy has its own separate, equal bucket. CMS updates these figures annually using the same formula applied to the Medicare Physician Fee Schedule conversion factor.1
Once a beneficiary’s combined PT and SLP charges reach $2,480, you must append the KX modifier to every therapy CPT code on subsequent claims—or Medicare will deny payment. The KX modifier signals to the MAC (Medicare Administrative Contractor) that the services are medically necessary and that the treating therapist has determined continued care is appropriate despite the threshold amount.
The Bipartisan Budget Act of 2018 permanently eliminated the old hard therapy cap, but the threshold requirement remained. Removing the hard denial was not an invitation to stop tracking. It was a shift to documentation accountability.
What KX Attestation Actually Commits You To
Appending KX is a clinical statement, not a billing shortcut. By adding KX, you are certifying that:
- The therapy services are medically necessary and clinically appropriate.
- The documentation in the medical record supports continued treatment beyond the threshold.
- Your patient’s progress is documented using objective, measurable functional outcomes.
That last point matters most in an audit. CMS requires progress documentation to include functional outcome measures—standardized tools like FOTO Patient Outcomes, OPTIMAL, or the AM-PAC “6-Clicks.” Generic statements like “patient tolerated treatment well” or “continues to make progress” do not satisfy the KX attestation standard.2
Your documentation should establish a clear clinical rationale: What functional limitation is being treated? What is the measurable goal? What is the expected endpoint of care? If you cannot answer those three questions from the note alone, the note is not audit-ready.
Targeted Medical Review at $3,000
CMS does not automatically audit every claim above the threshold. But at approximately $3,000 in combined therapy charges per beneficiary per year, CMS activates Targeted Medical Review (TMR). Under TMR, your MAC may request records before processing claims.
This is not punitive by design—it is a documentation review. If your notes are complete and support medical necessity, TMR is a manageable administrative event. If your documentation is thin, it can trigger a full prepayment review that delays cash flow for weeks.
Best practice: treat every note above the $2,480 threshold as though it will be reviewed. Short, vague progress notes written at the $1,200 mark become liabilities at the $3,000 mark.
RAC Audits on KX-Appended Claims
Recovery Audit Contractors (RACs) have consistently flagged outpatient therapy billing as a high-yield audit target. A RAC review of KX-appended claims typically looks for four things:
1. Missing or expired physician certification of the plan of care. KX claims require a valid, signed plan of care. If recertification has lapsed, every claim in the gap is at risk regardless of the clinical quality of care provided.
2. Missing or insufficient functional outcome measures. If the documentation does not show measurable functional progress—not just symptom reduction—the skilled care rationale is difficult to defend.
3. Maintenance therapy billed as skilled therapy. When a patient is maintaining function rather than improving, that is not a KX-qualifying situation. Continuing to bill skilled therapy codes on a maintenance-level patient is both a clinical documentation error and an overpayment risk.
4. Documentation that does not match the billing. Timed codes require specific time tracking. If the note does not reflect the units billed, every unit is vulnerable. The 8-minute rule applies to each timed code individually; a note that shows 10 total minutes of therapeutic exercise should not have two units of 97110 appended.
The OIG has repeatedly cited outpatient therapy as a billing area with elevated improper payment rates.3 RAC contractors know where to look.
Practical Workflow for Managing the Threshold
Running a clean KX workflow does not require expensive software. It requires process.
Track each patient’s running therapy dollar total. Your billing system should surface a dollar counter per beneficiary per year. If it does not, a simple manual log works. Build in a two-week advance alert before a patient hits $2,480.
Prime your therapists for documentation escalation. At approximately $2,200, begin writing stronger notes. Pull in a functional outcome measure score if one has not been completed recently. Document the specific activity limitation, the clinical reasoning for continued care, and the anticipated discharge milestone.
Confirm physician certification is current. KX claims without a valid, signed plan of care are denied and flagged. Review your recertification schedule any time a patient crosses the threshold. If recertification is due within 30 days, initiate it now.
Do not append KX to maintenance cases. If a patient’s realistic goal has shifted from recovery to maintenance, a skilled care attestation is clinically inaccurate and an audit risk. Have the discharge conversation and document it.
Build a TMR response packet in advance. Maintain a standard template: signed plan of care, progress note history, functional outcome measure scores, and a clinical narrative. When a MAC requests records, you want to respond in 48 hours, not scramble for two weeks.
The Bottom Line
The KX modifier exists to keep Medicare patients in care when they need it. Used correctly, it is a clean, defensible tool. Used carelessly—appended to thin documentation, maintenance cases, or unsigned plans of care—it becomes audit exposure.
Your billing team appends the modifier. Your clinical team owns the documentation. Both sides need to understand what KX commits the practice to—before the MAC asks.
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