The KX modifier and Medicare therapy threshold: 2026 rules.
The KX modifier is the single line item that decides whether a Medicare patient's therapy claims keep paying past a dollar line drawn once a calendar year — and it isn't a box to check, it's an attestation the medical record has to independently support. This guide covers the 2026 threshold figures, the separate and much higher targeted medical review threshold, exactly what documentation has to say to survive a KX-triggered review, the Jimmo v. Sebelius maintenance-therapy standard that governs a large share of KX claims, and what actually happens when a claim crosses the threshold without the modifier attached. Read this alongside the full physical therapy billing guide for how the threshold fits into the rest of PT's revenue cycle.
Key takeaways
- PT and SLP share one combined threshold; OT has its own, separate one. A practice billing both disciplines for the same patient has to track two running totals, not one — crossing the PT/SLP total doesn't automatically mean the OT total has crossed too, and vice versa.
- KX is an attestation, not a formality. Appending it without documentation that independently supports continued medical necessity is a false claim, and it's specifically the pattern a targeted medical review is built to catch.
- The targeted medical review threshold is a separate, much higher line from the KX threshold — crossing it makes a patient's claims eligible for a MAC-initiated review regardless of whether KX was correctly attached.
- Jimmo v. Sebelius did not create an "unlimited visits" standard. It confirmed that skilled maintenance therapy is covered when a licensed therapist's skill is genuinely required — the note still has to name that specific skilled component, not just state the patient benefits from continuing.
The 2026 threshold figures
Medicare tracks therapy spending against two separate dollar lines each calendar year, and confusing them is a common source of both under-caution (stopping short when nothing required it) and over-exposure (billing past a line that actually triggers review).
| Threshold | CY2026 figure | What crossing it triggers |
|---|---|---|
| KX modifier threshold, PT and SLP combined | “$2,480” in accumulated allowed charges — ⚠️ unverified against CMS's primary annual notice this build | Every subsequent PT and SLP claim line for that patient needs the KX modifier attached, with documentation on file supporting continued medical necessity |
| KX modifier threshold, OT | “$2,480” — ⚠️ unverified against CMS's primary annual notice this build | Tracked as its own separate running total; OT claims need KX once this total is crossed, independent of the combined PT/SLP total |
| Targeted medical review threshold | “$3,000” — ⚠️ unverified against CMS's primary annual notice this build | Patient's claims become eligible for a MAC-initiated medical review request — a materially different and more consequential event than the KX threshold, independent of whether KX is correctly attached |
⚠️ CMS's fee-schedule and therapy-threshold pages returned access errors to every automated retrieval attempt made while researching this page, so the figures above are stated with their usual industry sourcing rather than a primary-source pull confirmed this build. Verify the current-year threshold directly against the CMS therapy-services page or your MAC's published annual notice — both thresholds are indexed and typically change slightly year over year, so a figure that's correct for 2026 will not automatically be correct for 2027.
The distinction that matters operationally: the KX threshold is a documentation-and-modifier trigger, not a payment stop. Medicare will keep paying claims past it, provided KX is attached and the record supports the attestation. The targeted medical review threshold is a different kind of event entirely — it doesn't change what goes on the claim, it changes the odds that the MAC requests the underlying documentation before or after paying it. A patient can cross the KX threshold, have every subsequent claim correctly flagged with KX, and still be selected for review once their total crosses the higher targeted-review line; correct KX use doesn't exempt a claim from review, it just means the review should go the practice's way when it happens.
Tracking the running total
Both thresholds are calculated against the Medicare Physician Fee Schedule's allowed amount, not the practice's billed charge — the running total accumulates based on what Medicare actually allows for each service, summed across every date of service in the calendar year for that discipline. This has a practical consequence billing staff miss: a practice can't reliably predict the exact date a patient will cross the threshold just from billed charges, because the allowed amount (after any sequestration or other payment adjustment) is what the total is actually measured against.
- 1Track it in the billing system, not on a spreadsheet. A patient's running total needs to be visible at the point of claim creation, ideally with an automatic flag a set dollar amount before the threshold, so front-office and billing staff aren't discovering the crossing after a claim has already gone out without KX.
- 2Reset annually, per calendar year, per discipline. The threshold resets January 1 regardless of where a patient is mid-episode of care — a patient who crossed the threshold in November carries no KX obligation into the new year until the new year's accumulated total crosses the new year's threshold again.
- 3PT/SLP and OT are separate totals for the same patient. A patient receiving both PT and OT concurrently — common in a post-stroke or post-surgical rehab course — needs both totals tracked independently; crossing one doesn't imply anything about the other.
What the medical necessity attestation has to document
KX attests, on the claim itself, that the services billed are medically necessary and that documentation justifying continued treatment is on file. That's a specific, falsifiable claim about what the chart contains — not a general statement that the patient is still receiving PT. A targeted medical review checks exactly this: does the note actually say what the modifier claims it says.
- Names the specific, current functional limitation still being addressed — not the original referral diagnosis restated unchanged visit after visit.
- Describes the skilled intervention in terms that couldn't be replicated by a home exercise program or a caregiver — a technique being progressed, a safety risk being monitored, a plan being actively adjusted in response to the patient's response.
- Shows objective, measured progress where progress is the basis for continued treatment, or explicitly invokes the maintenance standard (below) where it isn't.
- Is dated and specific to that date of service, not a copy-forward note with only the date changed.
- Restates the original diagnosis with no update on current status or continued deficit.
- Describes activities a patient could perform unsupervised at home, with no clinical judgment named.
- States the patient "would decline without therapy" with no specific skilled component identified.
- Copy-forwards the prior visit's assessment and plan verbatim.
Appending KX without this level of specificity behind it is a false attestation on the claim, not a technicality — it's the exact gap a targeted medical review is designed to surface, and it's a recoupment risk on every claim in the reviewed sample, not just the one that gets pulled first.
Jimmo v. Sebelius and the maintenance therapy standard
The 2013 Jimmo v. Sebelius settlement is the legal basis for a large share of KX-threshold claims, and it's frequently misapplied in both directions — either treated as if it doesn't apply at all, or treated as a blanket justification for open-ended continued treatment.
Before Jimmo, an informal "improvement standard" had crept into how many payers and even some auditors evaluated therapy claims: coverage was assumed to require that the patient continue to show measurable functional improvement. The settlement made clear that standard was never the actual coverage rule. Skilled therapy is covered when the skilled service itself is necessary to maintain the patient's current condition, or to prevent or slow further decline, even where no further improvement is expected — a genuinely different and narrower standard than "the patient benefits from continuing."
The practical effect for KX-threshold claims specifically: a patient who has plateaued clinically is not automatically ineligible for continued, KX-attested therapy, but the documentation burden shifts entirely onto naming the skilled maintenance component. A note that simply stops mentioning progress, without affirmatively invoking and supporting the maintenance rationale, reads as a claim that quietly stopped being medically necessary rather than one that legitimately transitioned to maintenance care.
What happens when a claim crosses the threshold without KX
This is a hard system edit, not a soft flag a payer might choose to enforce. Once a patient's accumulated allowed charges for the calendar year cross the KX threshold, a subsequent claim line for that discipline submitted without KX attached denies for exceeding the therapy limit — the denial fires at the system edit level, before any human reviewer looks at the claim.
The fix at that point is almost always a corrected claim, not an appeal: attach KX, confirm the supporting documentation is genuinely on file, and resubmit, provided the timely-filing window for that payer hasn't closed. Where this becomes a real revenue problem is discovery lag — a practice that doesn't track the running total in its own billing system in real time typically finds out only when a batch of claims comes back denied days or weeks after submission, by which point staff time is spent re-billing a stack of claims in bulk rather than catching the crossing at the point the very first affected claim was created.
Set your billing system's KX warning flag at a dollar amount comfortably below the actual threshold — not exactly at it. Between the visit where the flag should fire and the visit where the claim is actually generated, additional charges from other same-week encounters can push a patient over the line faster than expected, especially for a patient in a high-frequency episode of care. A buffer catches that gap before it produces a denial instead of after.
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Frequently asked questions
What is the KX modifier threshold for physical therapy in 2026?
The KX modifier threshold for CY2026 is reported at $2,480 in accumulated allowed charges for PT and speech-language pathology combined, with OT tracked against its own separate $2,480 threshold. ⚠️ These figures could not be independently confirmed against CMS's primary annual notice during this build — CMS's fee-schedule and therapy-threshold pages returned access errors to automated retrieval — so confirm the current-year figure against your MAC's published notice or the CMS therapy-services page before relying on it operationally.
What has to be documented before appending KX to a claim past the threshold?
The medical record has to independently establish that continued skilled therapy is medically necessary — the specific functional deficit still being addressed, the skilled intervention (not a home-program-replaceable activity) being used to address it, and objective evidence of progress or, under the Jimmo v. Sebelius maintenance standard, why a licensed therapist's skill is still required even without further improvement. Simply noting that the original diagnosis is still present is not sufficient; KX is an attestation the documentation has to back up, not a formality appended once a running total crosses a number.
What happens if we bill past the KX threshold without appending KX?
The claim line denies for exceeding the therapy limit — this is a hard system edit at the clearinghouse or MAC level, not a soft flag, so it isn't a matter of the payer choosing to deny it. The fix at that point is a corrected claim with KX attached and supporting documentation on file, not typically an appeal, provided it's caught before the timely-filing window closes. Practices that don't track the running total in their billing system in real time are the ones that discover this after a batch of claims has already denied.
Verify before billing. CPT is a registered trademark of the American Medical Association; codes here are paraphrased, not reproduced from the CPT Professional edition. CPT, HCPCS and ICD-10 codes, coverage policy, and bundling edits change, including annual code-set updates. This page reflects standard industry practice and is provided for general education — it is not a substitute for your own compliance review, your current payer contracts, or the current-year code sets. Confirm requirements against your specific payer mix before submitting claims.