March 11, 2026
Rejections Due to Missing Modifiers on Nebulizer Claims (including Dispensing Fees)
Background: For dates of service on or after February 1, 2026, suppliers must add one of the KX, GA, or GZ modifiers to claims for ALL:
- Nebulizers
- Nebulizer related drugs
- Nebulizer related supplies
- Nebulizer dispensing fees
Issue: CGS rejected a high volume of these claims for missing modifiers. Suppliers asked how to correct these claims.
Scenario 1: Suppliers billed the claim without the KX, GA, or GZ modifier on any drugs, dispensing fees, supplies, etc. The entire claim was rejected with ANSI Reason Code CO-4.
Resolution 1: Resubmit the claim with the appropriate modifier (KX, GA, or GZ).
Scenario 2:Suppliers billed the KX, GA, or GZ modifier on the drug and supplies but not on the dispensing fee. Our system split the claim, rejected the dispensing fee with CO-4, and processed the rest of the claim correctly.
Resolution 2: Submit a written reopening request using one of the following options:
- myCGS Web Portal – Reopenings Form Submission Screen
- Reopen the paid drug claim and include a note to add the dispensing fee HCPCS to that claim. Include a request to add the KX modifier.
- Mail or fax the Medicare Reopening Request Form
. Include the following on the form:
- PTAN (one PTAN per form)
- Nebulizer drug HCPCS code (spanned codes are acceptable)
- Dispensing Fee HCPCS codes
- Date of service range
- Statement to append KX modifier
When submitting the Medicare Reopening Request Form for this issue, you aren't required to include the beneficiary's name, Medicare number, or Claim Control Number on the request. This process is being allowed as an exception instead of filing a Redetermination to add the KX modifier.
Resources:
Join Electronic Mailing List
Print
Bookmark
Facebook
YouTube
LinkedIn
CGS Medicare Mobile App