Thermo Fisher Scientific, the world leader in serving science, has introduced a groundbreaking laboratory developed test (LDT) designed to improve the detection and assessment of lung transplant rejection and injury. The new Molecular Microscope® Diagnostic System for Lung (MMDx® Lung) applies advanced machine learning and gene expression analysis to biopsy samples, offering clinicians quantifiable molecular insights that may enhance diagnostic accuracy and guide more personalized patient care.
Addressing the Challenge of Lung Transplant Rejection
Lung transplantation is a life-saving treatment for patients with end-stage lung disease, but it remains one of the most complex and high-risk transplant procedures. Recipients require frequent post-transplant monitoring, often through invasive lung biopsies, to detect early signs of rejection. However, traditional histopathological assessment of these biopsies is notoriously subjective — studies show that when evaluating the same lung biopsy, only 18% of pathologists reach consensus on the presence of acute rejection.
This diagnostic variability can delay critical treatment decisions and increase the risk of chronic graft damage. Thermo Fisher’s MMDx Lung was developed to address this challenge by providing objective, data-driven molecular analysis that supports more consistent and confident diagnoses.
Harnessing Machine Learning and Transcriptomics
The MMDx Lung system leverages the power of machine learning and transcriptome profiling to interpret gene expression data from lung transplant biopsies. Each new sample is compared against a reference database of more than 896 biopsies, representing a comprehensive molecular map of transplant outcomes.
By analyzing this large dataset, MMDx Lung generates molecular probability scores that indicate the likelihood of rejection, levels of graft injury, and patterns of dysfunction. These quantitative results complement a pathologist’s evaluation, offering a new dimension of diagnostic precision.
“The diagnosis of rejection and injury in lung transplants is very challenging,” said Dr. Phil Halloran, Director of the Alberta Transplant Applied Genomics Center and CEO of Transcriptome Sciences Inc. “Based on technology developed by investigators in the INTERLUNG study, we believe MMDx Lung will better diagnose rejection and detect Chronic Lung Allograft Dysfunction (CLAD)-related molecular changes. It provides a better guide for treatment and potentially for clinical trials, as a step toward improving the survival of lung transplants.”
The MMDx Lung system builds on Thermo Fisher’s existing Molecular Microscope® Diagnostic portfolio, which already includes solutions for kidney and heart transplant biopsies. The expansion into lung transplantation reflects a major advancement in molecular diagnostics for transplant medicine.
The Growing Need for Improved Lung Transplant Monitoring
Over the past decade, lung transplantation has nearly doubled in the United States, becoming an established therapy for patients with end-stage conditions such as idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), and cystic fibrosis. Despite advances in surgical techniques and immunosuppressive regimens, lung transplants continue to have lower long-term survival rates than other solid organ transplants.
The five-year survival rate for lung transplant recipients is just under 60%, primarily due to the challenges of early rejection detection and chronic lung allograft dysfunction (CLAD), a leading cause of long-term graft failure.
MMDx Lung aims to bridge the gap between traditional histology and modern molecular diagnostics by identifying rejection-associated changes earlier and more accurately — before irreversible tissue injury occurs.
“The launch of MMDx Lung enhances our comprehensive portfolio of post-transplant monitoring solutions and reflects our ongoing commitment to helping our customers personalize patient care and improve outcomes throughout the transplant journey,” said Tina Liedtky, President of Transplant Diagnostics at Thermo Fisher Scientific.
Expanding Clinical Access through Collaboration
In the United States, the MMDx Lung test is being made available through Kashi Clinical Laboratories, a CLIA-certified and CAP-accredited facility recognized for its leadership in transplantation immunodiagnostics. This collaboration ensures that transplant centers and clinicians can access MMDx Lung testing through a trusted laboratory partner with expertise in delivering molecular diagnostics for complex clinical needs.
“Accelerating clinical decision-making through the delivery of high-quality, rapid results is central to our mission of advancing health and healing to every patient we serve,” said Dr. Todd Johnson, CEO of Kashi Clinical Laboratories. “We’re proud to expand our collaboration with Thermo Fisher Transplant Diagnostics to deliver services for lung, in addition to kidney and heart transplant testing.”
MMDx Lung was developed and validated by Kashi Clinical Laboratories, LLC, and is currently available as a laboratory developed test (LDT) for clinical use. The test has not yet been cleared or approved by the U.S. Food and Drug Administration (FDA) or CE marked in the European Union as an in vitro diagnostic (IVD).
Integrating Molecular Insights into Transplant Care
The introduction of MMDx Lung represents more than a new test — it signifies a shift toward precision transplant medicine. By using genomic and transcriptomic data to detect rejection and injury at the molecular level, clinicians can move beyond purely histological interpretation and base decisions on objective, reproducible evidence.
The system’s quantitative scoring framework may also enable physicians to monitor disease progression, assess treatment response, and identify candidates for novel therapies or clinical trials targeting graft dysfunction. Over time, this molecular approach could lead to earlier interventions, fewer unnecessary treatments, and improved long-term outcomes for patients.
For pathologists and transplant clinicians, MMDx Lung serves as an additional layer of diagnostic intelligence, helping to bridge the gap between tissue morphology and molecular biology.
A Step Forward in Molecular Transplant Diagnostics
Thermo Fisher’s launch of MMDx Lung underscores its commitment to advancing transplant diagnostics through innovation, technology, and strategic collaboration. The company continues to expand its suite of molecular tools designed to help clinicians make more informed decisions and improve the lives of transplant recipients.
The Molecular Microscope® platform — originally pioneered by Dr. Halloran and his team — now provides integrated solutions for kidney, heart, and lung transplants, each supported by robust molecular databases and machine learning algorithms. Together, these assays offer clinicians a unified approach to understanding graft health across multiple organ types.
