Frequently Asked Questions

Published 09/21/2022

(M00086, V23)

The following are frequently asked questions about the Molecular Diagnostic Program.

MolDX General Questions

What is the purpose of the MolDX program?
To identify tests, determine coverage, and determine reimbursement.

  1. How does this program help claim adjudication?
    Once the required information is received and a DEX Z-Code™ identifier is assigned, Palmetto MolDX can determine coverage and payment without documentation review. This process removes the need for the provider to submit large amounts of additional information with every claim and expedites claim payment.
  2. What laboratories will be affected?
    All private, reference and hospital laboratories that perform molecular diagnostic testing and submit claims to Medicare in JE, JF, JJ, JM, J15, J5 or J8 on forms CMS 1500 (Part B), UB04 (Part A) or electronic claims on a 5010-837P (Part B) or 837I (Part A) are affected by this program. (Please reference the specific jurisdiction MDT policy for effective dates.)
  3. What molecular diagnostic assays/tests are included in MolDX?
    Please visit the MolDX website for an up to date list of CPT® codes that are within the MolDX scope of work. Submit questions about specific tests/assays not described in this chart to
  4. Is the MolDX Program national in scope?
    The MolDX Program currently covers JE (American Samoa, Calif., Guam, Hawaii, Nev., North Mariana Islands), JF (Ark., Ariz., Idaho, Mont., N.D., Ore., S.D., Utah, Wash., Wyo.), JM (N.C., S.C., Va., W.Va.), J15 (Ky., Ohio), JJ (Tenn., Ga., Ala.) J5 (Iowa, Mo., Kan., Neb.), and J8 (Mich., Ind.). The role-out of JJ by Palmetto GBA began in early 2018. Labs that perform services for patients in those states have been notified to begin DEX Z-Code™ registration. Claims submitted after June 1, 2018, must have a Z-Code.
  5. How does a lab register a test?
    Review DEX Test Registration and Claims Submission for instructions.
  6. What is DEX™ Diagnostics Exchange’s involvement in the MolDX program?

    MolDX will leverage the Diagnostics Exchange™ (DEX), the online test catalog.

    DEX is a web-based service designed to identify tests and help establish transparency in the evidence-based coverage of them. This tool enables labs to confidentially share test information with MolDX online. Please visit DEX™ Diagnostics Exchange Registry.
  7. What information will be made available to the public?
    MolDX information collected for the registry will only be available to those labs electing to submit a DEX Z-Code™ identifier application and is consistent with the public/private indications therein.

Who are the Medicare Administrative Contractors (MAC) Medical Directors of Palmetto GBA?

Gabriel Alejandro Bien-Willner, M.D., Ph.D., is the Medical Director of the MolDX program at Palmetto GBA, which seeks to understand the molecular testing landscape to implement payer controls and coverage, and to set policy. He is a leader in the Precision Medicine space and practices as a board-certified Anatomic Pathologist and Molecular Genetic Pathologist. Dr. Bien-Willner received his M.D. and Ph.D. from Baylor College of Medicine, with a doctorate in Human Molecular Genetics. His clinical training and academic tenure were at Washington University in St. Louis. Throughout his career, he has been active in research, development and advancement of molecular diagnostic services, specifically next-generation sequencing. His experience spans both academia and industry. He has worked closely with clinicians to develop clear clinical diagnostic and treatment pathways directing Precision Medicine programs for community cancer centers.

Angella Charnot-Katsikas, M.D., is a Medical Director for the MolDX program at Palmetto GBA. She is a board-certified Clinical Pathologist with subspecialty training in Clinical Microbiology, Molecular Genomic Pathology and Clinical Medical Ethics. Dr. Charnot-Katsikas received her M.D. degree from Rush Medical College in Chicago, and then completed her residency and fellowship training at the University of Chicago where she served as an Associate Professor of Pathology. She has also worked as a Medical Director of multiple laboratories, and has been involved in numerous research, education, quality and diagnostic stewardship initiatives throughout her career.

Magdalena Jurkiewicz M.D., Ph.D., M.P.H. is a Medical Director for the MolDX program at Palmetto GBA. She is a board-certified Clinical and Molecular Genetic Pathologist. Dr. Jurkiewicz received her M.D. and Ph.D. degree in Genetics from SUNY Stony Brook following completion of the Medical Scientist Training Program.  She also holds an MPH from the Yale School of Public Health and completed her residency and fellowship training at New York-Presbyterian Hospital/Columbia University in New York City. She has authored numerous research articles in the field of human genetics and molecular diagnostics and has clinical industry experience as a laboratory director of oncology and molecular pathologist.

MolDX Registration (Z-Code Aplications)

  1. Should the manufacturer or the performing lab register an FDA-approved, in vitro diagnostic test that utilizes a kit?
    The manufacturer and the performing labs should submit an application. The MolDX team will review each submission for accuracy and assign each performing lab that reports the test without modifications the same code. The lab must submit an application in order to obtain a DEX Z-Code™ identifier for submission. Without the application information, MolDX cannot determine the kit is unmodified and the labs that intend to use the kit.
  2. If multiple tests may be performed and billed within one assay, is the lab required to register each test within the assay?
    A DEX Z-Code™ identifier application is required for a single assay that may involve multiple tests in order to produce a single result.
  3. Is a unique identifier application required for an FDA-approved test?
    Yes. 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 Medicare coverage.
  4. After a test is granted a unique identifier, can a hospital bill their respective MAC directly for the test using the assigned DEX Z-Code™ identifier?
    Yes. Effective March 1, 2017, hospitals must add the DEX Z-Code™ identifier in block 80 of the UB04 claim form or on line SV202-7 of the 837I electronic claim.
  5. Is a unique identifier required for tests billed with a NOC code?
    Yes. Review DEX Test Registration and Claims Submission.
  6. Are labs expected to register tests sent to another lab to perform?
    Both labs must register as an organization in DEX. The performing lab submits the test details to receive the Z-code. If you send your labs to a reference lab to be performed, you will need to request “sharing” in DEX in order to obtain access to the Z-code. The billing lab uses the Z-code of the performing lab. The two labs link up in DEX with a Sharing Request. Labs will only request Z-codes for tests that are performed in house. You are required to register your organization in the DEX Diagnostics Exchange if you plan to submit claims to jurisdictions that implement MolDX.
  7. If a lab performs the same exact test from two different locations, operating under two different CLIA numbers, will the lab be required to submit both tests for unique identifiers?
    If the test process is standardized and the same method is used to acquire the results in both locations, labs will only have to submit one application for the test. However, if there is a difference in the method, an application will be required from both locations.
  8. If the kit used in an LDT is not FDA-approved, should the lab apply for a unique identifier for that kit?
  9. Are labs required to register tests that use a code in the MolDX code range and a code that is not listed in the MolDX range of codes?
    Yes. Labs must register tests that include MolDX and non-MolDX range of codes in the test panel. MolDX will map only the test(s) in the MolDX range of codes. (i.e., EGFR by molecular methodology and ROS1 and ALK by IHC)
  10. When a laboratory modifies an FDA approved kit, will MolDX require a new unique identifier?
    Yes. If a lab modifies a registered test, the resulting test is considered an LDT and will require a separate application.
  11. Are hospital labs that file institutional claims and providers that file professional claims exempt from the requirement to obtain a unique identifier?
    Providers submitting institutional claims are required to submit claims with DEX Z- Codes. Physicians submitting professional claims (-PC or -26) are not required to use DEX Z-Codes™.

Billing and Coding

  1. What are the effective dates of the Z-codes?
    After DEX assigns a Z-code to a lab for a specific test, the MolDX team will review the test application and will assign a CPT® code to the test. The Z-code can be submitted on claims once it is mapped by MolDX and entered into the master edit file for claims adjudication.
  2. What action should a lab take if they believe they may have incorrectly billed for a MolDX service?
    If you believe your practice has made a MolDX billing/coding error, you may take the following corrective actions:
  • Complete a self-audit
    • Identify incorrect submissions
    • Prevent further claim submission errors
  • Consider self-disclosure protocol
    • Self-disclosure guidelines available on the OIG website


  1. Will ABN's be valid with the unique identifier?
    The DEX Z-Code™ identifier is only additional information, not a billing code.
  2. Will MolDX pay test services provided prior to the TA approval date?
    All new test services will be denied as noncovered until the test completes the TA process and reasonable and necessary criteria is established. Claims submission for tests in the TA process should be suspended until a final coverage determination is made.
  3. Is the reimbursement for a flow cytometry affected by MolDX?
    Palmetto GBA has an active LCD for Flow Cytometry and will continue to administer coverage as published in that policy the same as any other active policy.