What it signals:-KX is the provider’s attestation to Medicare that outpatient therapy services are medically necessary and reasonable beyond the annual therapy threshold, and that supporting documentation exists in the medical record.
Enables payment above the cap: Without -KX, any Medicare outpatient therapy claim over the threshold is automatically denied. Appending -KX is the mechanism that triggers the automatic exception to continue coverage.
Not a reduction modifier:-KX does not reduce payment. It is a compliance attestation that unlocks continued reimbursement.
Does not guarantee payment: Appending -KX does not guarantee coverage. Medicare contractors may still review the claim and deny for lack of documented medical necessity.
CY 2026 Medicare Therapy Thresholds
Discipline Bucket
CY 2026 Threshold
Targeted Medical Review Threshold
PT + SLP combined
$2,480
$3,000
OT (separate bucket)
$2,480
$3,000
PT and SLP share a single combined threshold. Every dollar of PT and SLP services for a patient within a calendar year counts toward the same $2,480 bucket.
OT has its own separate $2,480 threshold that does not intermingle with PT/SLP.
These are incurred expense thresholds (what Medicare counts/allows), not the billed charges.
Thresholds reset every January 1 (calendar year, not per episode of care).
Core Medicare/CMS rules (high yield)
Apply -KX at the point of crossing the threshold:-KX is not applied to all claims — only to claim lines for services rendered at or above the threshold dollar amount. Claims below the threshold do not need -KX.
Apply to each applicable line:-KX must be on every over-threshold claim line for the applicable discipline. It is not a one-time modifier applied to the first over-threshold claim and forgotten.
Discipline modifier always paired:-KX always stacks with the applicable discipline modifier: -GP for PT, -GO for OT, -GN for SLP. All three are on the same line when over threshold.
**Targeted Medical Review (MR) threshold — 3,000:∗∗Whenthepatient′sincurredtherapyexpensesexceed3,000 (for PT/SLP or OT), the claim is flagged for potential targeted medical review by the Medicare contractor. -KX is still required; the provider just needs to be prepared to submit records if reviewed.
Functional reporting: CMS eliminated the mandatory G-code functional reporting requirement for therapy services (effective 2019), so no G-codes are required alongside -KX in current billing.
GA modifier interaction: If you believe the service is medically necessary but expect Medicare may deny (e.g., documentation is borderline), -GA is used to document that an ABN was issued to the patient. -GA and -KX are generally not stacked together — if you’re confident in medical necessity, use -KX; if you’re not, issue an ABN and use -GA.
Documentation checklist (what to show)
Medical necessity clearly established in the record: Documentation must demonstrate that the patient’s condition requires continued skilled therapy — that without ongoing skilled intervention, the patient’s functional status would decline or they cannot achieve their maximum expected functional status.
Functional progress documented: Show measurable progress toward established goals. Lack of progress without a clear clinical rationale is a red flag for audit.
Plan of care recertification current: The POC must be recertified by the physician/NPP. A lapsed POC means -KX means nothing — the claim can still be denied.
Skilled need documented: The record must support that the services require the skills of a licensed therapist (PT, OT, or SLP) and cannot be safely or effectively performed by an unskilled caregiver.
Audit-ready: Once -KX is used, the claim is on Medicare’s radar. Ensure every note that corresponds to a -KX claim line is defensible on its own.
PT exercise by PTA, over threshold; 15% CQ reduction + KX required
Payer considerations
Medicare Part B:-KX is required above the threshold. No -KX = automatic denial above $2,480.
Medicare Advantage (replacement plans): Many MA plans follow Medicare’s -KX rules, but some have different threshold amounts or require prior auth at a certain dollar level. Always verify individual plan policy (Humana, UHC Medicare Advantage, Aetna Medicare, BCBS Medicare supplemental, etc.).
Commercial payers (UHC, BCBS, Aetna, Cigna):-KX is a Medicare-specific modifier. Commercial payers typically do not use or require -KX — their medical necessity attestation occurs via prior authorization rather than a claim modifier.
Wisconsin Medicaid: Verify ForwardHealth therapy billing guidance — Medicaid does not necessarily follow the Medicare therapy threshold framework.
Quick self-check (before you append -KX)
Has the patient’s Medicare-incurred therapy expense reached or exceeded $2,480 for the applicable discipline bucket this calendar year?
Is there a current, signed plan of care and adequate documentation supporting continued skilled need?
Is the discipline modifier (-GP, -GO, or -GN) also on the same line?
If the patient’s expenses are approaching or exceed $3,000, is the documentation exceptionally thorough in preparation for targeted medical review?
If you are not confident in medical necessity (borderline documentation), have you issued an ABN and used -GA instead of -KX?
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