Modifier KX
Requirements specified in the medical policy have been met
Use it when
- Durable medical equipment where the policy's coverage criteria are documented
- Therapy services exceeding a threshold where continued care is justified and documented
- Any item or service whose policy specifies KX as the attestation of met criteria
Do not use it when
- The documentation has not been obtained or verified
- The criteria are partly met and the gap has not been resolved
- Routinely, as a default appended to every claim in a category
A worked example
A supplier furnishes an item of durable medical equipment. The policy requires a face-to-face encounter within a defined window, clinical records supporting medical necessity, and a written order before delivery.
Where all three are present and have been read against the policy, modifier KX attests to that and the claim is submitted. Where the clinical records were requested but never received, KX is not supportable — the criteria may well be met clinically, and the file does not establish it.
The distinction matters because the attestation is about the documentation, not about the patient's condition.
What decides it
KX is widely treated as a required character that unlocks payment, which is exactly backwards. Applying it to items whose documentation has not been verified converts a paperwork gap into a false attestation.
The usage pattern is auditable in aggregate. A supplier appending KX to essentially every claim in a category is visible in claims data before any chart is reviewed, and that pattern is what selects a supplier for review.
Where criteria are not met, different modifiers apply, and they do not make the claim payable. Choosing correctly between them is a judgement made before submission about what the file actually contains.
Denial codes this affects
Modifiers often confused with this one
Terms used here — Medical Necessity · Prior Authorization · Denial
How we handle it — Denial Management · Eligibility Verification · Claims Management
Every CPT and HCPCS modifier with a guide
Coverage attestation
- GAWaiver of Liability, ABN on File
- KXMedical Policy Requirements Met
Evaluation and management
Global period
Multiple and bilateral
Primary sources
What the payers and code-set maintainers actually publish about modifier KX.
- DMEPOS supplier standards and enrollment (opens in a new tab)
Centers for Medicare & Medicaid Services — Supplier enrollment requirements and documentation standards for durable medical equipment, prosthetics, orthotics and supplies.
- Medicare Coverage Database (LCD/NCD) (opens in a new tab)
Centers for Medicare & Medicaid Services — Searchable national and local coverage determinations. The direct answer to whether a diagnosis supports medical necessity for a given procedure.
- HCPCS Level II code set (opens in a new tab)
Centers for Medicare & Medicaid Services — Codes for supplies, drugs, DME and services outside CPT — and the modifier definitions that go with them.
Questions about modifier KX
That the coverage criteria in the applicable medical policy are met and that supporting documentation is on file. It is a statement about the documentation, not about the patient's clinical condition, and not a character that makes claims pay.
No. If the clinical records were requested but not received, the criteria may well be met clinically while the file fails to establish it. The attestation is about the file.
Yes. A supplier appending KX to essentially every claim in a category is visible in aggregate claims data before any chart is reviewed, and that pattern is what selects a supplier for review.
Different modifiers apply, and they do not make the claim payable. Where the patient is to be billed, an Advance Beneficiary Notice and modifier GA are the relevant instruments.
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