MolDx Broadens Transplant Testing Coverage—but Keeps a Firm Hand on the Rules
A closely watched final policy
MolDx has finalized LCD L40140, Molecular Testing for Organ Allograft Rejection, replacing the draft issued in summer 2025. The policy governs Medicare coverage for tests such as donor-derived cell-free DNA and gene-expression profiling, used either when rejection is suspected or to monitor an apparently stable transplant recipient for subclinical injury.
These assays share an analytical challenge with noninvasive prenatal testing and plasma cancer testing: they must find a very small signal within a much larger background. In transplantation, that signal may be DNA released from injured cells in a donor kidney, heart, lung, or other graft.
But the Medicare question is not simply whether the signal can be detected. It is whether the result is clinically valid, changes management, reduces reliance on biopsy, and is useful often enough to justify repeated payment.
The final policy opens the door
Compared with the draft, the final LCD is meaningfully more favorable to laboratories and transplant programs.
For kidney recipients, MolDx raised first-year surveillance from four tests to six. During years two and three, the general allowance increased from two tests annually to four. Heart and lung surveillance remained at as many as 12 tests during the first year.
The final policy also gives more attention to multiorgan transplantation, including simultaneous pancreas-kidney recipients, and creates a path for testing in organs beyond kidney, heart, and lung. It incorporates additional kidney gene-expression evidence and softens the draft’s near-prohibition on performing a molecular test and biopsy during the same clinical episode.
Another important change concerns paired testing in heart transplantation. The draft was skeptical that combining gene-expression profiling with donor-derived cell-free DNA added enough value. The final LCD acknowledges evidence that an integrated noninvasive strategy may reduce biopsies without worsening outcomes. MolDx therefore leaves room for a qualifying combined service, while still resisting routine payment for multiple separately billed tests.
More coverage, more boundaries
The policy became broader, but not looser.
MolDx retained the one-service-per-encounter principle, discouraged routine pairing of molecular testing with biopsy, and required later-year surveillance schedules to be supported by evidence for the particular organ, analyte, population, and intended use.
The distinction between surveillance and “for-cause” testing also became more important. Surveillance is scheduled testing in an otherwise stable patient. For-cause testing occurs when there is a documented clinical concern for rejection.
The final LCD defines that distinction better than earlier policies, but it still leaves a troublesome gap. It does not say how large or persistent a creatinine increase must be, which physiological changes clearly qualify, or when a transient abnormality becomes sufficient evidence of suspected rejection.
That creates a post-payment problem. A nephrologist may reasonably conclude that a change in graft function justifies testing, while a MolDx reviewer later decides the evidence was too weak. The policy requires documentation but offers no true safe harbor.
Why 194 pages mattered
The response-to-comments document runs an extraordinary 194 pages. That length reflects the stakes.
Moving kidney surveillance from four to six first-year tests raises potential testing volume by 50 percent. Doubling years-two-and-three surveillance can add four claims per eligible patient. Small wording changes concerning combination testing, biopsy, or multiorgan recipients can therefore shift tens of millions of dollars in laboratory revenue and materially affect investor expectations.
Commenters won several important concessions, but they did not win unlimited surveillance, automatic payment for multiple tests, or deference to physician preference alone.
The mind of MolDx
The final policy reveals a familiar MolDx posture: receptive to noninvasive, biopsy-sparing technology, but highly skeptical of open-ended utilization.
MolDx will broaden coverage when presented with specific evidence tied to a particular test, organ, patient population, and clinical use. It is far less persuaded by general enthusiasm, professional preference, or the argument that more testing must be better.
Oue First Agentic LCD Analysis !
A new 15-page Discoveries in Health Policy white paper examines the draft, the final LCD, the coverage language, the comment record, and this broader MolDx policy mindset. First Chat GPT wrote that, then it wrote this summary.
It is also the first white paper in the series developed from a generic bullet-point instruction list alone—an agentic, or at least agentic-like, use of AI to find, compare, reorganize, and interpret a complex Medicare policy record.
White paper here.