February 01, 2024

Make sure molecular tests have a Z-Code assigned

Beginning April 1, 2024, UnitedHealthcare commercial plans will require DEX Z-Codes® for certain molecular diagnostic test services on facility and professional claims for the claims to be considered for reimbursement. This is part of our updated Molecular Pathology Reimbursement Policy, Professional and Facility.

New DEX Z-Code phased submission

We’ll be requiring DEX Z-Codes on claims in phases based on the type of test that’s being performed. To better help you prepare for this upcoming change and to help ensure there’s no disruption in your payment, please begin to register phase 1 codes before April 1.

We’ll require these codes for dates of service on or after April 1, 2024, for the claim to be considered for reimbursement. We’ll notify you on future phase timing. If you haven’t already obtained a DEX Z-Code for your test, please register by visiting

Services requiring Z-Codes for phase 1

You’ll need to register with the DEX registry for Z-Code for the following services:

  • Adult molecular diagnostic tests relevant to Medicare age population, except inherited cancer testing
  • Prenatal carrier screening tests
  • Specific services billed under 81479 
    • Genetic disease carrier status for procreative management
    • Pharmacogenomics testing (PGx), including single-gene and multi-gene panels

We’re planning additional phases later in 2024 for other molecular pathology services. Once we have exact dates, we’ll publish a Network News article so you can prepare accordingly.

After test registration is complete

Once you’ve completed the test registration, the initial review for Z-Code assignment takes approximately 2 weeks from the test submission. We’ll then email you the notification that the test has been assigned a recommended CPT® code and you can submit the Z-Code and  CPT code together on claims. This typically occurs within 60 days from the initial Z-Code assignment.

We may require additional documentation dependent on test complexity. For further guidance on the timeline for the registration of your tests, refer to the DEX test registration.

Fixing claim errors

If you submit electronic claims that have errors, we’ll send you a Smart Edits message within 24 hours of submission. You can open the Smart Edits guide and use Ctrl + F  to search for the following edits to correct the issue:

Professional edit Facility edit

Visit for more information or contact the Electronic Data Interchange (EDI) support team at or call 800-842-1109.


Questions? We're here to help.

Connect with us through chat 24/7 in the UnitedHealthcare Provider Portal. For additional contact information, visit our Contact us page.

PCA-1-24-01223 Clinical-EM_01172024

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