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Industry Insights

What is MolDX and When Do I Need a Z-Code?

Information provided by Tami Shaw, Client Manager, Lighthouse Lab Services

Palmetto and WPS delayed enforcement of the LCD highlighted in this article until May 17, 2022.

The LCD highlighted in this article went into effect for CGS and Noridian on June 2, 2022.

Laboratories performing infectious disease testing and billing Medicare Part B within a MolDX jurisdiction are subject to a new Local Coverage Determination (LCD) that stands to significantly impact reimbursement for these services.

Labs in the impacted MACs (Noridian, Palmetto, CGS, and WPS) are required as of April 17, 2022, to register for a unique DEX code z-identifier through the Diagnostic Exchange to receive a fixed reimbursement for laboratory developed tests (LDTs) or “expanded” panels that test for more than five targets.

Read on below to learn more about the history of the MolDX program, the purpose of Z-Codes, and the process labs need to take to complete this registration in order to continue being able to bill for impacted tests.


The history and purpose of MolDX

MolDX Map

Current states participating in the MolDX Program

The Molecular Diagnostic Services (MolDX) Program was developed by Palmetto GBA in 2011 to identify and establish coverage reimbursement for molecular diagnostic tests. This program currently provides uniform policies for 28 states, across four Medicare Administrative Contractors (MACs).

MolDX defines a consolidated set of LCDs, articles, and coding edits. The other participating MACs operate using the MolDX program based on joint agreements. The program primarily performs the following functions:

  • Facilitates detailed and unique identification through registration of molecular diagnostic tests to facilitate claims processing and to track utilization.
  • Establishes clinical utility expectations.
  • Completes technical assessments of published test data to determine clinical utility and coverage.
  • Establishes reimbursement rates.
Schedule a Free MolDX Consultation


What’s a DEX Z-Code?

The Diagnostic Exchange (DEX) Z-Code Identifier is a unique five-character alpha-numeric code associated with certain molecular diagnostics tests and is used by some payers as an adjunct to non-specific CPT codes. This code is unique to a lab’s specific molecular diagnostic test (MDT), or LDT.

This code, submitted on a claim, in addition to the CPT/HCPCS code, provides clarity to help ensure that both payers and providers clearly understand which test is being ordered, performed, and billed.


When do I need to obtain a Z-Code?

Laboratories seeking coverage for the following types of tests must obtain a test ID:

  • LDT or MDT reported using an unlisted code
  • Test reported with a Tier 1 or Tier 2 CPT code
  • FDA-approved version of an MDT test (if multiple, identical versions of the test are available, including tests that have not been approved by the FDA)
  • All versions of a single test performed in multiple laboratories (to the extent that each laboratory performs the test differently)
  • Modified version of an FDA-approved IVD


How does reimbursement for infectious disease testing stand to be impacted by this new LCD?

Effective April 17, infectious disease panels performed and billed in MolDX jurisdictions are subject to a new LCD: Molecular Syndromic Panels for Infectious Disease Pathogen Identification Testing.

Prior to the introduction of this LCD, ID panels testing for more than five pathogens were not reimbursed for any reason. Only three to five pathogens were considered medically necessary.

The expanded panels listed in this LCD are:

  • Respiratory panels
  • Pneumonia panels
  • Gastrointestinal panels
  • Urogenital panels
  • Anogenital panels
  • Meningoencephalitis panels
  • Bloodstream Infection panels
  • Urinary Tract Infection panels

The panels not mentioned in this LCD, but that are affected by it, could include:

  • Sexually Transmitted Infection panels
  • Women’s Health panel
  • Wound panels
  • Nail and Fungal panels

Expanded panels will now require an ID specialist to order. There are exceptions for rural and remote areas where access to an ID specialist is unreasonable. In general, the exception would require that the ordering provider is located closer to the patient’s residence than the nearest specialist.

Some of the guidance on ID specialists includes:

  • For Immune-competent beneficiaries, must be ordered by:
    • Pulmonologist for respiratory and pneumonia panels who is treating the patient.
    • Gastroenterologist for GI panels who is treating the patient.
  • For Immune-compromised beneficiaries
    • Must be ordered by a Clinician Specialist
      • Infectious Disease (Any Panel) Must be treating patient.
      • Oncology (Any Panel) Must be treating patient.
      • Transplant (Any Panel) Must be treating patient.
      • Pulmonologist (for Respiratory and Pneumonia panels) Must be treating patient.

Panels that continue to target three to five pathogens will not require an ID specialist.


What steps should our lab be taking now if we haven’t already registered my tests?

Most ID panels, including RPP and GI expanded panels (more than five pathogens) will need to be registered with the MolDX and have a DEX Z-code assigned to them, which will create established pricing. If the lab has not already registered with the MolDX program, there are three primary steps:

  • Register with MolDX program. Each lab can have two representatives assigned access.
  • Register the tests.
  • Submit a Technical Assessment.

This process can take approximately 60 to 90 days to complete.

While it may require a fair amount of front-end work, there are benefits to receiving MolDX Z-Codes. Receiving a fixed rate for your tests allows labs to create a consistent pricing model, even if reimbursement in some instances is lower. This will also reduce denials, similar to a preauthorization process. In short, your staff or billing team will face fewer hurdles to get reimbursed for your services.

If you need assistance with registering for a DEX Z-Code, completing a technical assessment, or any other step in this process, Lighthouse has the technical and RCM expertise to guide you and ensure you continue receiving the maximum reimbursement when billing Medicare for these services.

Schedule a free consultation with us today!


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