Missing/Invalid Molecular Diagnostic Services (MolDX) DEX Z-Code™ Identifier

CARC/RARC Description
CO-252 An attachment/other documentation is required to adjudicate this claim/service.
N706 Missing documentation.
N704 Alert: You may not appeal this decision but can resubmit this claim/service with corrected information if warranted.

Common Reasons for Message

  • Claim line submitted is missing DEX Z-Code™ identifier
  • DEX Z-Code™ identifier submitted is invalid
  • CPT code cannot be billed with submitted DEX Z-Code™ identifier

Next Step

  • Verify correct CPT code is billed
  • Verify correct DEX Z-Code™ identifier is billed for the CPT code submitted

Claim Submission Tips

  • Submit only one DEX Z-Code™ identifier per MolDX CPT
  • Submit DEX Z-Code™ identifier in Loop 2400/SV101-7
  • Do not submit any other characters or test names. Doing so will slow claims processing and possibly cause incorrect denials
  • Visit our MolDX webpage for additional information.
Last Updated Apr 30 , 2025