Key takeaways
- KX means the requirements in the applicable medical policy have been met, and the records to prove it are on file.
- For outpatient therapy, add KX once the allowed amount for a patient passes the annual threshold: $2,480 for PT and SLP combined in 2026. OT has its own threshold.
- For DME, add KX only on items whose coverage policy calls for it, and only when every criterion is met.
- Therapy lines above the threshold without KX are denied. A separate $3,000 threshold can bring a targeted medical review.
What the KX modifier means
Modifier KX stands for "requirements specified in the medical policy have been met." It is an attestation. By adding it, you confirm that the coverage criteria in the policy that governs the service are met for this patient on this date, and that records proving it are on file.
The modifier has no meaning of its own. Its meaning comes from the policy it sits under, which is why the same two letters appear on therapy claims and on DME claims for very different reasons.
KX modifier for outpatient therapy (PT, OT and SLP)
Medicare no longer has a hard cap on outpatient therapy. Since 2018 it has an annual threshold per patient instead. Once the allowed amount for a patient reaches it, each further line needs KX to be paid, and the notes must show why therapy is still medically necessary.
| Item | 2026 figure | What it does |
|---|---|---|
| KX threshold, PT and SLP combined | $2,480 | Lines at and above it need KX or are denied |
| KX threshold, OT | Separate from PT and SLP | OT is counted on its own |
| Targeted medical review threshold | $3,000 | Claims above it can be selected for record review |
The thresholds are counted per patient per calendar year, based on allowed amounts, and they reset every January 1. CMS updates the figures each year, so check the annual therapy update before the new year starts.
Report KX together with the therapy modifier for the discipline: GP for physical therapy, GO for occupational therapy and GN for speech-language pathology.
KX modifier for DME and supplies
For durable medical equipment, prosthetics, orthotics and supplies, KX goes only on items whose Local Coverage Determination or policy article requires it. It tells the DME MAC that the supplier has confirmed the coverage criteria and that the supporting documents are on file and available on request.
- Glucose monitors and supplies: KX goes on the claim when the patient is treated with insulin injections, and stays off when the patient is not.
- Oxygen and oxygen equipment: KX goes on each oxygen code once the coverage requirements are met.
- Other items with KX requirements include external infusion pumps, commodes and ankle-foot orthoses, depending on the policy.
If the criteria are not met, KX stays off. The policy then points you to GA or GZ instead, depending on whether a signed ABN is on file.
How to decide whether to add KX
- Name the policy that applies: the therapy threshold rules, or the LCD and policy article for the DME item.
- Check that every criterion is met for this patient, on this date, for this item.
- Confirm that the records show it.
- For therapy, add up the allowed amounts for the year and start adding KX on the lines that reach the threshold.
KX threshold checker
Enter the allowed amount so far this year and the allowed amount for the next visit. The checker shows whether KX is needed.
PT and SLP are counted together. OT has its own threshold, so enter the OT figure from the CMS annual therapy update for OT patients. The targeted medical review threshold is $3,000.
Common KX mistakes
- Adding KX to every claim from the first visit. It belongs on the lines at and above the threshold.
- Counting PT and SLP separately. They share one threshold.
- Adding KX after a denial without checking the criteria. For DME this is the wrong use of the modifier.
- Leaving KX off above the threshold. Those lines are denied.
- Using KX on a DME item whose policy does not call for it.
- Adding KX without notes that support it. KX is an attestation, and claims can be reviewed after payment.
A DME claim denied only over KX is appealed through a written redetermination. A claim rejected as unprocessable with remark code MA130 has no appeal rights: correct it and resubmit.
KX modifier FAQ
What does the KX modifier mean?
KX means the requirements specified in the medical policy have been met. It attests that the coverage criteria for the service or item are satisfied and that the records are on file.
What is the KX modifier threshold for 2026?
For 2026 it is $2,480 for physical therapy and speech-language pathology combined, per patient per calendar year. Occupational therapy has its own threshold. A separate $3,000 threshold applies to targeted medical review.
Is the KX modifier a therapy cap?
No. Medicare repealed the hard therapy caps. Therapy above the threshold is still covered when it is medically necessary, but each line must carry KX and the records must support it.
When is the KX modifier used on DME claims?
Only when the Local Coverage Determination or policy article for the item requires it, and only when every coverage criterion is met and documented. If the criteria are not met, the policy points to GA or GZ instead.
Does the KX modifier apply to commercial plans such as Aetna?
The 2026 therapy threshold and the KX rules in this guide are Medicare rules. Commercial plans, including Aetna, set their own policies and may use KX differently or not at all, so check the payer policy for the specific service before adding it.
How do I explain the KX modifier to a patient?
KX is a billing attestation, not a charge to the patient. It tells Medicare that the provider holds records showing the service meets the coverage criteria. For the patient it means the therapy or equipment stays covered as long as medical necessity is documented.
Is the KX modifier still valid?
Yes. Medicare still uses KX to show that the requirements in the medical policy have been met, including for outpatient therapy services above the annual threshold. The threshold amount is updated each year, so use the current figure from CMS and not a figure from a prior year.
Is the KX modifier only for Medicare?
KX is defined by Medicare and appears mainly on Medicare claims. Some other payers adopt it or use their own rules, so check each payer policy before you add it to a non-Medicare claim.
When should the KX modifier be added to a claim?
Add it when the policy requirement is met and your record supports it. For therapy, that means the patient services have passed the annual threshold and the documentation shows the care is medically necessary. Do not add it by default to every line.
Is the KX modifier used for insulin-dependent patients?
KX also appears on some Medicare supply claims, such as diabetic testing supplies, where a coverage requirement has been met. The condition depends on the policy for that item. The meaning is the same: the requirements in the policy are met and documented.
Related: physical therapy billing services and denial management.