The KX Modifier and Medicare Therapy Thresholds (CY 2026)

Every year, therapists relearn the same two numbers and the same two misconceptions. The numbers for CY 2026: $2,480 (the KX modifier threshold) and $3,000 (the targeted medical review threshold). The misconceptions: that either number is a cap on care, and that crossing the second one means an audit. Neither is true, and the details matter because the failure mode is immediate: claims above the KX threshold without the modifier are denied outright.

This guide works from the primary sources: the Medicare Claims Processing Manual, Chapter 5, §10.2–10.5 (Pub. 100-04), CMS Transmittal R13437CP (the CY 2026 threshold update, issued October 30, 2025), and the CMS therapy services page. Figures are current as of August 2026.

The two thresholds, side by side

Note the pairing rule, because it trips people up: physical therapy and speech-language pathology share one accrual bucket. A patient who used $1,500 of SLP services this year has only $980 of headroom before their PT claims need the KX modifier. Occupational therapy accrues separately.

Why this isn’t called a “cap” anymore

The vocabulary is historical residue. The Balanced Budget Act of 1997 created hard dollar caps on outpatient therapy. Congress then spent two decades softening them: an exceptions process from 2006, and finally the Bipartisan Budget Act of 2018, which repealed the caps entirely. What survived is the reporting mechanic: the dollar amount where you must start attesting that continued therapy is medically necessary. That attestation is the KX modifier. Medicare pays above the threshold indefinitely, as long as the care is justified and the modifier is on the claim.

What actually counts toward the threshold

Three details determine when a patient crosses:

1. It accrues on Medicare-allowed amounts, not your billed charges. The tracking system applies the Medicare Physician Fee Schedule allowed amount before adjustment for beneficiary liability (Manual §10.4), so the patient’s deductible and coinsurance portions count toward the threshold too.
2. It accrues per beneficiary, per calendar year, across all providers and settings. Your clinic’s records only show your share. A patient who did a post-surgical episode at another practice in March arrives at your clinic in August already partway to the threshold. Settings covered include private practice, hospital outpatient departments, rehab agencies, CORFs, and SNF Part B.
3. You can look it up. Providers can check a beneficiary’s accrued amount through the 270/271 eligibility inquiry (or your MAC’s portal), and beneficiaries see their accrual on their Medicare Summary Notices (Manual §10.5.B). Checking accrual at evaluation for patients with prior therapy this year should be routine intake work, not a surprise at claim denial.

What appending KX actually means

The KX modifier is not paperwork. Per Manual §10.3, appending it is a formal attestation that the services:

• are reasonable and necessary and require the skills of a therapist (Pub. 100-02, Ch. 15, §220.2),
• are justified by appropriate documentation in the medical record (§220.3), and
• qualify for the exception process.

The manual is blunt about the consequences: “If this attestation is determined to be inaccurate, the provider/supplier is subject to sanctions resulting from providing inaccurate information on a claim.” KX is a signed statement, made per claim line, with your enrollment on the line.

When to add it (and when not to)

The manual’s guidance differs by claim type, and both directions have a failure mode:

• Too late: claims above the threshold without KX are denied (group code PR, claim adjustment reason code 119, “benefit maximum reached”). PR means the denial lands as patient responsibility, which is a billing-office and patient-relations problem, not just lost revenue. Contractors may reopen and adjust if it’s brought to their attention, but that’s remediation, not workflow.
• Too early: the manual explicitly calls premature KX use abusive. For professional claims, “use of the KX modifier when there is no indication that the cap is likely to be exceeded is abusive,” with the example of low-cost services early in an episode. Don’t blanket-apply KX from visit one.
• Institutional claims have a different rule: once any line on the claim exceeds the threshold, KX goes on all lines of that claim belonging to the same threshold bucket (all PT and SLP lines, for instance), regardless of whether each line individually exceeds it (Manual §10.4).

KX also rides alongside the discipline modifiers (GP for PT, GO for OT, GN for SLP), which are required on therapy lines regardless of thresholds. The discipline modifier is how the tracking system knows which bucket a dollar accrues to.

The documentation that has to stand behind it

The manual’s most quotable warning (§10.3, emphasis CMS’s own): “It is very important to recognize that most conditions would not ordinarily result in services exceeding the cap. Routine use of the KX modifier for all patients with these conditions will likely show up on data analysis as aberrant and invite inquiry.”

What justifies exceeding the threshold is not the diagnosis; it’s the patient-specific complexity. The manual directs clinicians to document the condition or complexity that “directly and significantly impacts the rate of recovery,” and it explicitly allows non-clinical factors that affect appropriate treatment (for example, caregiver availability at home) to be considered. Generic goals and copied-forward daily notes are precisely what data analysis flags: the same diagnosis, the same clinic, and one provider’s KX rate far above peers.

If your KX claims describe why this patient needs continued skilled care, in terms a reviewer can trace through the treatment time and progress documentation already in the record, the modifier is defensible. If your KX usage pattern is “everyone who crosses $2,480,” expect scrutiny.

The $3,000 threshold: targeted, not automatic

Crossing $3,000 does not trigger a review. It makes claims eligible for the targeted medical review process, which has been in place since the BBA of 2018 and is funded and bounded by statute through 2028. Selection is targeted at outliers: CMS points review contractors at factors like aberrant billing patterns relative to peers, high claim denial percentages, and questionable billing practices. An ordinary practice with clean documentation and a normal KX distribution can have many patients above $3,000 and never see a records request.

The practical takeaway is the same one as the KX section: the threshold system runs on pattern analysis. The defense isn’t avoiding the thresholds; it’s not being an outlier, and having documentation that survives the request if one comes.

Where the ABN fits

Above the threshold, two different situations call for different paperwork (Manual §10.5):

• Care is still medically necessary (you’re billing with KX): no ABN is required. A voluntary ABN is permitted as a courtesy notice of the threshold, but the patient shouldn’t be asked to sign or choose an option on a voluntary notice.
• Care no longer meets medical necessity (goals met, plateau, maintenance without skilled need): a mandatory ABN must be issued before delivering the service. Without a valid ABN, you generally can’t hold the beneficiary liable for a medical-necessity denial. This is the scenario where practices lose money quietly: continuing to treat past necessity, skipping the ABN, and eating the denials.

The decision point, in other words, is clinical necessity, not the dollar amount. The threshold just determines which modifier and which notice apply.

A workflow that handles all of this

1. At evaluation: if the patient had any therapy this calendar year (anywhere), check accrual via eligibility inquiry. Note the shared PT + SLP bucket.
2. During the episode: track allowed-amount accrual against $2,480, not visit counts. Dollar accrual varies with the codes billed.
3. Approaching the threshold: confirm the record documents patient-specific complexity supporting continued skilled care. This is the moment to strengthen documentation, before the first KX claim.
4. At the threshold: append KX (with the correct GP/GO/GN modifier) per the professional or institutional rule above. If care is no longer necessary, that’s an ABN conversation instead.
5. Ongoing: watch your own KX rate. If every Medicare patient crosses the threshold, be able to explain why your case mix produces that, because the data analysis will ask the question eventually.

Quick answers

Does the threshold reset? Yes, every January 1, per beneficiary.

Does my patient’s deductible count toward it? Yes. Accrual uses the Medicare-allowed amount, which includes the beneficiary’s share.

Do other clinics’ services count? Yes. Accrual is per beneficiary across all providers and settings, which is why checking eligibility matters.

Is there a dollar amount where Medicare stops paying? No. With medical necessity, documentation, and the KX modifier, there is no upper limit. Without them, payment effectively stops at $2,480.

Do Medicare Advantage plans use these thresholds? These rules govern Original Medicare. MA plans run their own utilization management (often prior authorization instead), so check plan policy; don’t assume the KX mechanics transfer.

What happens if I forget KX on a claim above the threshold? Denial with reason code 119 as patient responsibility. Contact your MAC about reopening the claim with the modifier if the care qualified.

Threshold problems are workflow problems: the information exists, but it isn’t in front of the right person at the right moment. PrismEHR lets organizations define their own billing rules, including minute and unit restrictions, enforced at the point of documentation and reinforced at claim creation, so payer-specific requirements get caught while the note is still open rather than on a remittance. Start with our 8-minute rule guide for the unit-counting layer underneath everything in this post.