Reimbursement Updated June 19, 2026

How to Get a Molecular Test Covered: A Practical Market-Access Roadmap

Getting a new molecular or genetic test from validated to paid runs through MolDX registration, a DEX Z-Code, a technical assessment, coding and pricing, and commercial payer coverage. This roadmap walks each stage and what it actually takes.

How to Get a Molecular Test Covered: A Practical Market-Access Roadmap

Educational disclaimer. This article is for general educational purposes only. It is not legal, billing, regulatory, or reimbursement advice. Coding, coverage, and payer processes change frequently, and requirements differ by Medicare Administrative Contractor, by payer, and by test. Verify current MolDX, DEX, and individual payer requirements directly with the relevant source, and consult qualified professionals before acting. CPT and PLA codes are referenced by number only. Use this information at your own risk.

You have a validated assay. The analytical work is done — limits of detection nailed down, reproducibility studies signed off, the whole binder of validation data sitting on a shared drive. Clinicians who have seen the data want to order it. And then someone in finance asks the question that stops the celebration cold: how, exactly, do we get paid for this?

It turns out that developing a molecular test and getting a molecular test reimbursed are two almost entirely separate disciplines. The first is science. The second is a market-access process with its own registry, its own dossiers, its own coding rules, and dozens of payers who each decide for themselves. Labs that treat reimbursement as an afterthought routinely run claims for months and collect almost nothing.

This is the roadmap from "developed" to "covered and paid." It runs through five stages: registering the lab and test in the DEX Diagnostics Exchange, completing a MolDX technical assessment, obtaining a DEX Z-Code, sorting out coding and pricing, and finally pursuing commercial payer coverage and contracting. None of these stages is a formality, and the order matters.

Stage 1: Register the lab and test in DEX

For most molecular tests, the front door is the MolDX Program — the Molecular Diagnostic Services program Palmetto GBA developed in 2011 to identify molecular diagnostic tests and establish coverage and reimbursement for them (Palmetto GBA). MolDX provides uniform policies across four Medicare Administrative Contractors (MACs): Palmetto GBA, Noridian Healthcare Solutions, CGS, and WPS, covering a large block of states (Noridian).

The mechanism MolDX uses to identify each test is the DEX Diagnostics Exchange, a web-based registry that Palmetto GBA administers (dexzcodes.com). Labs in the impacted MACs are required to register their tests through DEX — particularly laboratory-developed tests (LDTs) and expanded panels that test for more than five targets (Lighthouse Lab Services). You create an account at dexzcodes.com, register the laboratory, and submit the specific test.

It helps to frame this stage correctly: registration catalogs your test so it can be tracked and so a claim can later be processed. It is the entry point, not the finish line. The substantive review that decides whether Medicare will pay comes next.

Stage 2: Complete the MolDX technical assessment

The technical assessment is where coverage is actually won or lost. MolDX reviews the clinical information for a new test to determine whether it meets Medicare's reasonable-and-necessary requirement (Palmetto GBA Technical Assessment). In MolDX's own words, the program will only cover and reimburse tests that demonstrate analytical validity, clinical validity, and clinical utility at a level that meets that standard (MolDX FAQ via Streamline). CMS has directed MolDX to follow the ACCE framework the CDC developed — analytical validity, clinical validity, clinical utility, and the associated ethical, legal, and social implications.

Those first three terms are worth slowing down on, because payers everywhere — not just Medicare — organize their thinking around them:

  • Analytical validity asks whether the test accurately measures what it claims to measure. This is most of your validation binder: sensitivity, specificity, reproducibility, the boundary conditions of the assay. MolDX expects analytical validation that establishes those boundary conditions, generally using clinical specimens — samples from patients with the relevant disorder — rather than only contrived or purchased reference material (MolDX FAQ via Streamline).
  • Clinical validity asks whether a result actually correlates with the disease, risk, or outcome it claims to predict (Managed Healthcare Executive).
  • Clinical utility asks the harder question: does using this test lead to measurable improvements in how the patient is managed or how they fare? (Managed Healthcare Executive).

The gap between the last two is where a surprising number of well-built tests stall. A test can be beautifully valid — it predicts exactly what it says it predicts — and still fail to show that acting on the result changes anything for the patient. Payers consistently weigh tests with both clinical validity and utility more favorably than tests with validity alone, because actionability rises when a result informs management rather than merely confirming a diagnosis already in hand (Managed Healthcare Executive).

Practically, this stage means assembling a dossier. MolDX expects a table of contents of all submitted materials, a summary of the test's background and intended use — who should be tested, when, and why — and any professional-society or clinical guidelines addressing the test's use (Palmetto GBA Technical Assessment). MolDX also offers a pre-submission process that lets developers get feedback on dossier materials before a formal technical assessment, though it does not change the requirements or the review timeline (Palmetto GBA Technical Assessment).

One structural detail can save you months. MolDX maintains foundational LCDs, sometimes called umbrella policies, that lay out general criteria for a class of tests. A foundational LCD can cover future tests on a rolling basis when MolDX determines they show "equivalent or superior performance to covered tests" with similar indicated uses (Discoveries in Health Policy). If your test fits an existing foundational policy, your path can be considerably shorter than starting from a blank coverage determination. Timelines for technical assessment vary by test and by the completeness of your dossier, so treat any duration you hear as approximate and verify the current expectation.

Stage 3: Obtain the DEX Z-Code — and understand what it does not do

Once a test is registered, DEX assigns it a DEX Z-Code: a unique five-character alphanumeric identifier that pins down exactly which test was performed, on a claim, at your specific lab (dexzcodes.com). On a molecular claim, the Z-Code is how a payer knows that the CPT code in front of them refers to your specific assay and not one of the dozens of other tests that might share the same CPT code.

Here is the single most important thing to internalize about the Z-Code: it identifies your test; it does not establish coverage. A Z-Code can be assigned within roughly two weeks of submission, but it is not effective for claims until the DEX clinical team reviews the application, determines coverage, and assigns the appropriate CPT code (Lighthouse Lab Services). The Z-Code alone does not make a test payable; coverage and reimbursement are assigned to the Z-Code only after that review (dexzcodes.com General FAQs). Plenty of labs have celebrated receiving a Z-Code only to discover that the actual coverage decision was still ahead of them.

Stage 4: Sort out coding and pricing

With identity and coverage taking shape, the test needs a code that carries a price. Two families matter here. Standard CPT molecular pathology codes describe categories of testing. PLA (Proprietary Laboratory Analyses) codes are a specialized addition to the CPT set, created after CMS's June 2016 final rule, that let a specific lab or manufacturer uniquely identify its advanced diagnostic or FDA-cleared test rather than share a generic code (AMA). If your test is distinctive enough, a PLA code can describe it precisely; if not, you may land on an existing CPT code that DEX recommends during registration.

Pricing on the Clinical Laboratory Fee Schedule generally follows one of two methods. A new code is crosswalked when its payment rate is set by comparison to a similar existing code. When no comparable assay exists, CMS uses gapfill: the MACs individually price the test in the first year, and in the second year CMS adopts the median of those contractor-specific prices to set a national limitation amount (Association for Molecular Pathology). In setting a rate, MACs consider charges and routine discounts, the cost of resources to perform the test, amounts other payers pay, and the pricing of comparable tests.

The takeaway for planning: a price is not a fixed number you can assume in advance. Crosswalk and gapfill can produce very different outcomes, and gapfill in particular plays out over a multi-year cycle. Build your financial model around a range, and verify current pricing rather than anchoring on a figure you saw last year.

Stage 5: Pursue commercial payer coverage and contracting

Medicare is rarely the whole story. Commercial payers run their own show, and getting paid by them is its own multi-front campaign.

The encouraging news is that the MolDX infrastructure increasingly extends beyond Medicare. Commercial payers including UnitedHealthcare and Humana have adopted the DEX and Z-Code framework for certain molecular tests nationwide, regardless of MAC region (Lighthouse Lab Services), and many commercial medical policies reference MolDX-style criteria — the same analytical validity, clinical validity, and clinical utility tests you assembled evidence for in Stage 2. The work you did for Medicare is not wasted; it is the foundation of your commercial dossier.

But each payer still maintains its own medical policy and decides coverage on its own terms, and being covered is not the same as being in network. Two distinct tracks run here. The first is coverage: persuading the payer's medical policy team that the test is medically necessary for a defined population, again with that validity-versus-utility distinction front and center. The second is contracting and credentialing: negotiating an in-network agreement and a rate, and completing the payer's credentialing of your lab. These processes take time and vary widely by payer and by test; rather than promise a specific number of weeks, plan for an ongoing, multi-payer effort and staff it accordingly.

When the evidence base is genuinely promising but not yet conclusive, there is an interim path worth knowing. Coverage with Evidence Development (CED) lets Medicare cover an item or service on the condition that data gathered through a clinical study or registry will determine its effectiveness, used when available evidence is insufficient to support coverage outright (CMS). CED coverage is typically time-limited, and CMS encourages sponsors to build interim analyses into their study design to ease the transition to full coverage (CMS CED Guidance). It is not a shortcut — it is a structured way to keep generating the utility evidence payers want while patients get access.

Getting covered is the start, not the finish

Walk the full roadmap and you arrive somewhere that feels like a destination: a registered test, a Z-Code, a coverage determination, a price, and a handful of payer contracts. It is a real milestone. It is also the moment the maintenance problem begins.

Coverage is not static. MolDX policies get revised. Commercial payers update medical policies, tighten medical-necessity language, change which indications they will pay for, and revise documentation requirements — each on its own schedule. A test that is reliably paid this quarter can start denying next quarter because one payer rewrote one policy for one indication, and nobody on the revenue-cycle side caught the change until the denials piled up. The hard part of reimbursement, in other words, is not getting covered once. It is staying paid as every payer's criteria drift, per test and per indication.

That is the gap Converus is built to close: keeping each payer's evolving coverage criteria encoded and current for every test and every indication, so the policy reality your claims meet today is the one your team is actually working from. The roadmap gets you covered. Keeping the criteria current is how you stay paid.

Sources

Frequently Asked Questions

Does a DEX Z-Code mean my test is covered?
No. A DEX Z-Code is a unique identifier that tells a payer exactly which molecular test was performed on a claim. Coverage is a separate determination made by MolDX after its clinical team reviews your application and technical assessment, and by each commercial payer under its own medical policy.
What does the MolDX technical assessment actually evaluate?
MolDX evaluates a test's analytical validity, clinical validity, and clinical utility, and determines whether the test meets Medicare's reasonable-and-necessary requirement. CMS has directed MolDX to follow the ACCE framework. Tests that do not demonstrate clinical utility at that level are generally not covered.
What is the difference between clinical validity and clinical utility?
Clinical validity is how well a test result correlates with the disease, risk, or outcome it claims to predict. Clinical utility is whether using the test leads to measurable improvements in patient management or health outcomes. Payers frequently cover tests with strong validity only when there is also evidence of utility.
Do commercial payers use MolDX and Z-Codes too?
Many do. Commercial payers such as UnitedHealthcare and Humana have adopted the DEX and Z-Code infrastructure for certain molecular tests nationwide, regardless of MAC region, and many reference MolDX criteria in their own coverage policies. Each payer still maintains its own medical policy and contracting process.
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