HCPCS Modifier KX
Requirements Specified in the Medical Policy Have Been Met
Source: AMA CPT / CMS HCPCS Level II definitions. Maintained by the D3rx Clinical Billing Team.
What modifier KX means
Modifier KX attests that the documented coverage requirements in the applicable Medicare policy (LCD/NCD, DMEPOS policy, or the therapy threshold rules) have been met. It is most familiar in outpatient therapy, where it certifies that services exceeding the annual KX threshold amount remain medically necessary, and in DMEPOS, where it certifies the item's coverage criteria are satisfied.
When to use it
Append once a patient's therapy reaches the annual KX threshold and continued treatment is medically necessary, or on a DMEPOS/policy-driven claim where the record meets every coverage criterion in the policy.
Documentation checklist
The record should support every item below before you append modifier KX.
- Medical-necessity documentation supporting continued/qualifying services
- For therapy, tracking that the threshold was reached and why ongoing care is required
- The specific LCD/NCD or DMEPOS criteria that are met
- Functional status / progress supporting continued treatment
Do NOT use modifier KX when
- The policy requirements are not actually met (KX is an attestation, not a bypass)
- It is being used solely to push a claim past an edit without supporting documentation
- A different, more specific policy modifier is required
Common denial reasons
- KX appended without records that actually support the policy criteria
- Therapy threshold not reached, making the attestation inapplicable
- Documentation does not establish continued medical necessity on review
How to appeal a modifier KX denial
On denial, submit the records that satisfy each element of the cited LCD/NCD or therapy threshold and a brief statement mapping the documentation to the policy criteria. Emphasize functional progress and continued medical necessity for therapy beyond the threshold.
Payer notes
For therapy, the KX threshold (indexed annually by CMS) replaced the former hard therapy caps; KX certifies the chart supports medically necessary care beyond that amount. A separate, higher targeted-medical-review threshold also applies. Commercial use of KX is limited and policy-specific.
Related & commonly confused modifiers
Where modifier KX is used
- Physical/occupational therapy (97110, 97112, 97140, 97530)
- DMEPOS (braces, supplies)
- Policy-gated diagnostic services
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Medical billing disclaimer
Modifier definitions follow standard AMA CPT and CMS HCPCS Level II guidance and are for educational reference. Payer policies, billing formats, and coverage rules vary and change. Always verify the current rule with the specific payer before submitting. D3rx is not responsible for claim outcomes.