The KX modifier is a payment modifier used almost exclusively with HCPCS codes. It signifies to the payer, whether Medicare or not, that the claim for whatever DMEPOS you are billing, has corroborative documentation in the patients’ chart meeting the insurance company’s requirements.
Every orthotic and prosthetic device code along with all therapeutic shoe claims must contain a KX modifier on every claim line. Without the KX modifier the third party, especially Medicare, will reject the claim on the front end. That means the claim will be rejected and be sent back to you as unprocessable. This type of claim will not cross over or be manually sent to the secondary carrier for payment.
In instances where you want Medicare to reject a claim and ascribe the payment to the patient or the secondary insurance carrier, one should refrain from using the KX modifier and instead use the GY modifier (statutorily non covered service) or GA modifier (not covered on this DOS as the patient may have had this service too frequently based on the coverage criteria).
Simultaneous use of the GA or GY and the KX modifier again will lead to an unprocessable claim which will be returned to your office.
In short, the KX modifier should be used for DMEPOS when the policy requires it (AFO, lower limb prosthesis and therapeutic shoes) but only when the patient’s chart documentation can corroborate the requirements listed in the LCD.
