General FAQs

Published 09/01/2023

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

DEX General FAQs (PDF)

Program Overview

DEX is a web-based application designed to identify tests and help establish transparency between providers and payers. 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 the DEX Diagnostics Exchange Registry to login and use the platform

  • Medicare contractors participating in the MolDX® program:
    • JM A/B (N.C., S.C., Va., W.Va.) and JJ A/B (Tenn., Ga., Ala.) administered by Palmetto GBA
    • JE A/B (American Samoa, Calif., Guam, Hawaii, Nev., North Marina Islands) and JF A/B (Ark., Ariz., Idaho, Mont., N.D., Ore., S.D., Utah, Wash., Wyo.) administered by Noridian Healthcare Solutions.
    • J5 A/B (Iowa, Mo., Kan., Neb.) and J8 A/B (Mich., Ind.) administered by WPS Government Health Administrators.
    • J15 A/B (Ky., Ohio) administered by CGS Administrators, LLC.
    • For more information and directions pertaining to the MolDX program, please visit their website at
  • Participating payers will direct you to register in DEX and obtain Z-Codes if and when required. Current participating programs:
    • UnitedHealthcare® (Medicare Advantage and Commercial)
  • 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 (subject to change)
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
Microbiology Procedure (DNA, RNA based tests only)
Infectious Disease* 81513, 81514, 87154, 87483, 87505-87507, 87631-87633, 87636, 87637
Unlisted 87999
Other 87800, 87801

*NOTE: At this time, molecular syndromic panels for infectious disease pathogen identification that are FDA-cleared/approved do not require a Z-Code unless the panel meets specific criteria. See Test Submission Requirements(#9) below for more information.

Registration Topics

Visit the DEX Diagnostics Exchange Registry 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 (2) 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.

The following fields are visible to public users of the DEX Registry: test name, lab test ID, lab/manufacturer name, lab test description, FDA 510(k)/PMA status and associated FDA document number, handling instructions, turnaround time, specimen information, patient instructions, MolDX Price, and MolDX Coverage determination. DEX Z-Codes are not publicly available.

As an administrator in the DEX Registry, you will be able to control privacy for other fields for your tests under your Organization’s Test Privacy settings.

Both the performing lab and client lab must register as an organization in DEX Registry. 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). More information on using the Sharing feature can be found in the DEX Administrator FAQs (PDF).

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. Ensure you enter your test as it is orderable to providers on your test requisition. A DEX Z-Code is assigned to individual orderable tests and/or panels and not to CPT® codes.

If the test process is standardized and the same method is used to acquire results in both locations, the 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 (PDF) 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 clearance and approval processes ensure only the clinical and analytical validity of the test. The FDA does not include clinical utility in their review, which is required for a technical assessment. If a laboratory modifies an FDA-cleared/approved test, the resulting test is considered a LDT (laboratory developed test) and will require a Z-Code.

*NOTE: At this time, molecular syndromic panels for infectious disease pathogen identification that are FDA-cleared/approved do not require a Z-Code unless the panel meets any of the criteria below:

  • If the FDA-cleared/approved test is being used outside of its intended use labeling (i.e., it is modified in any way) it requires a Z-Code.
  • If no specific CPT or PLA code exists for the panel, it will be billed with CPT code 87999. Molecular tests using CPT code 87999 requires a Z-Code, regardless of FDA-clearance/approval status.
  • If you perform multiple (>1) FDA-cleared/approved molecular infectious disease pathogen identification tests on the same date of service (DOS), for the same intended use on the same patient sample, it is considered one distinct service and requires a Z-Code.

Refer to the Molecular Syndromic Panels for Infectious Disease FAQs for more information.

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) Evaluation

If additional documents are needed for the TA, 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, 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 by default will be considered Not Successful. However, you may submit your technical assessment documentation at any time after the deadline for review.

Please refer to the Technical Assessment page for information on where to submit requested TA documents.

Tests will be updated with a TA Result of Not Successful for the following reasons:

  • The TA documentation submitted does not demonstrate analytical validity, clinical validity, and/or clinical utility per established TA evaluation procedures.
  • The requested TA documentation was not received.
  • The type of service submitted has not been established to have medical necessity.

For billing/claims related inquiries, please contact the participating payer.

Claims Related

After DEX® assigns a Z-Code for a specific test, a Technical Assessment (TA) may be performed, and a result determined at the completion of the assessment. The Z-Code is effective and can be submitted on claims once the test has been assigned a TA result or has been assigned a recommended CPT® code.

  • For tests that do not require additional TA documentation, this is complete in approximately 3-4 weeks.
  • For tests that have submitted additional TA documentation, this process can take up to 60 days.

Once the TA review process is complete, you will receive an email notification and the TA evaluation result will be updated in the DEX Registry.

DEX Customer Service is not able to address claims related questions. Please contact your payer directly for assistance.