General FAQs

The following are frequently asked questions about the DEX™ Diagnostics Exchange Registry and Z-Code™ Program.

Program Overview

DEX is a web-based application designed to identify tests and help establish transparency between providers and payors, using evidence-based coverage determinations. This tool enables labs to confidentially share test information with participating payers online. Labs register as an entity on the platform and submit their tests for review. Please visit to login and use the platform.
  • Medicare contractors participating in the MolDX® program:
    • JM, JJ A/B administered by Palmetto GBA
    • JE, JF A/B administered by Noridian Healthcare Solutions
    • J5, J8 A/B administered by WPS Government Health Administrators
    • J15 A/B administered by CGS Administrators, LLC
    • For more information and directions pertaining to the MolDX program, please visit their website at
  • Medicare Advantage Programs: Participating payers will direct you to register in DEX and obtain Z-Codes if and when required. Current participating programs:
    • United Healthcare
  • Other payers participating with DEX (Requirements may vary):
    • Medical Mutual of Ohio
    • Fallon Health
    • Blue Cross® and Blue Shield® of North Carolina
Note: Please review applicable payer policies for specific CPT® codes.
Test Group Options CPT Code Range*
MoPath Tier 1 81105-81112, 81120-81121, 81161-81364, 81374, 81377, 81381, 81383
MoPath Tier 2 81400-81408
Genomic Sequencing Procedures 81410-81471, 81493
Unlisted 81479, 81599
MAAA codes 81504-81595, 0004M-0013M, 0016M, 0017M (DNA, RNA based molecular codes only)
PLA codes Molecular codes only

*This list is subject to change.

Registration Topics

Visit the DEX™ Diagnostics Exchange Registry at and select ‘Register as a Lab or Hospital’ on the log in page. Complete the registration form to gain access to the DEX Registry. If you receive a notification that your organization’s NPI # or CLIA # is already registered, please contact us at for assistance.
An organization can have two registered users. A registered user for an organization gets a username that is specific to the contact person designated by each laboratory. Please do not forward or share this information. Other colleagues within your organization who want to register, may apply for a public user account. A public user account allows viewing of public information, which does not include Z-Codes.
DEX Z-Codes™ are not publicly visible. Public users may register in DEX and view test details that are publicly available which may include coverage and price information assessed by the MolDX program.
Both the performing lab and client lab must register as an organization in DEX. Only the performing lab needs to add the test to obtain a Z-Code. The client lab will need an approved sharing request from the reference lab to obtain the Z-Code for the send out test(s). Please review the DEX Sharing FAQs listed here.

Test Submission Requirements

Select the ‘Add Test’ action button from the Catalog Overview or My Diagnostics Exchange tabs within DEX. Complete all required fields and submit for review. For more information, see the DEX Diagnostics Exchange Help Files.
When adding a test, use the tooltip buttons to identify required information and view helpful hints. For example, the Test Description should succinctly describe the test’s intended use, indications for ordering, and limitations. PGx tests should include the intended drug(s) of interest in the description.
A DEX Z-Code™ identifier application is required for a single assay that may involve multiple tests in order to produce a single result. Z-Codes are assigned to tests or panels as they are orderable and not based on individual CPT® codes.
If the test process is standardized and the same method is used to acquire results in both locations, lab will only have to submit one application for the test. However, if there is a difference in the method, a separate application will be required for both locations.
It is not necessary to apply for a new Z-Code when you make changes to a test. Please log into DEX and update the existing test record with the new information. If the changes are significant enough to constitute a new test, such as a methodology change or additional specimen types, a new Z-Code may be assigned.
Yes, in the event a test is retired, please update your DEX test submission to reflect this change. The DEX Registry relies on accurate data entry and maintenance. Please review the DEX Administrator FAQs for specific instructions.
Yes, labs must register tests that include MDx and non-MDx range of codes in the test panel.
Both the manufacturer and the performing labs should submit an application. The DEX clinical team will review the applications and assign a Z-Code to the manufacturer’s submission. Each performing lab that submits an application and performs the test without modifications will receive the same Z-Code. Without the application information, it cannot be determined whether or not the kit has been modified and/or how the lab intends to use the kit.
Yes, a Z-Code application is required in both scenarios. The FDA approval process ensures only the clinical and analytical validity of the test. The FDA does not include clinical utility in their review, which is required to establish coverage. If a laboratory modifies an FDA-approved test, the resulting test is considered a LDT (laboratory developed test) and will require a separate application and Z-Code for claims submission.
Yes, an application for a unique identifier will be required if the test has a CPT code within scope for requiring a DEX Z-Code.
We recommend the laboratory wait until the FDA determination is complete to add that information to your test in DEX.
An algorithm may be considered a meaningful and independent component of a laboratory process when ALL the following conditions are met:
  • It is an unambiguous problem-solving operation that includes deploying a set of rules or calculations requiring computer processing;
  • The test result (or a component of the result) is the calculated output of this process, and not an intermediary process;
  • The same or similar test result could not be obtained without the use of this process;
  • The input for the computation is derived from biological samples using analytical processes, and must include data from the sample submitted for the test;
  • The process must:
    • Either be required for the analytical result, OR
    • If adjunct to the analytical result as a post-analytical process, the calculation itself must be independently found to be reasonable and necessary apart from the other components of the test.

Technical Assessment (TA) Documentation

If technical assessment documents are needed to evaluate coverage, you will be notified by email. Once notified, please submit all completed documentation within 15 calendar days. In general, additional documentation is needed for more complex testing. For example, all NGS-based tests require additional documentation and form submission.
We recommend completing all aspects of test validation prior to registering for a Z-Code to prevent delays. If the 15-day deadline is missed, your test will not have demonstrated compliance with relevant standards and policies and by default will not be covered by most payors. However, you may submit your technical assessment documentation at any time after the deadline for review. Your test will remain in a not covered status until the technical assessment review is completed successfully.
Please send completed documentation to

Coverage Related

After DEX assigns a Z-Code for a specific test, a technical assessment is performed. Coverage is usually determined at the completion of the assessment. The Z-Code becomes effective and can be submitted on claims when that process is complete, and the test is assigned a recommended CPT® code and coverage decision based on applicable policies. For tests that do not require additional documentation, this is complete in approximately 3-4 weeks.
The DEX Registry is updated once per month with a recommended CPT® code and coverage decision, at which time you will be notified by email.
DEX Customer Service is not able to address claims related questions. Please contact your payer directly for assistance.

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