FDA’s Authority Over Lab-Developed Tests Overturned: What the Court’s Decision Means for Lab Testing

This article was co-authored by Katie Clowers (Research Consultant at Womble Bond Dickinson).

Previously, this blog covered the FDA’s decision to regulate lab-developed tests (LDTs) as medical devices.  However, a ruling from a federal district court in Texas earlier this year has changed that.  Multiple lawsuits were brought against the FDA and consolidated before a district court in the Eastern District of Texas.  The impetus behind the lawsuits were claims that treating LDTs as devices requiring FDA approval would create “massive compliance costs.”  Plaintiffs argued that LDTs were not devices, but services which are not subject to FDA regulation.  The district court agreed:

Although the FDCA’s text alone is enough to conclude that FDA lacks authority to regulate laboratory-developed test services as medical “devices,” see supra Part IV.B, the broader statutory framework of the FDCA and CLIA, and the historical underpinnings of these laws, reinforces the conclusion that the final rule attempts to assert authority over professional medical services that FDA lacks.

This decision allows providers to continue ordering specialized tests without expensive FDA review steps and should ensure that patients see consistent access and turnaround times. This regulatory shift is significant from a scientific standpoint because it places greater weight on each lab’s ability to design, validate, and monitor tests using physiology-driven standards rather than device-style premarket review.

At its core, the ruling underscores that lab-developed tests must reflect real human physiology, not just serve as laboratory instruments. LDTs are built around molecular biology; many of these tests measure molecules that change with disease, like troponin during a heart attack or cytokines during inflammation. These markers reflect real-time physiological changes rather than arbitrary numbers. Without FDA review, the responsibility for connecting a biomarker to its underlying biology—and ensuring the assay captures that biology accurately—rests primarily with the laboratory and the clinicians interpreting the results.

Translating this biological foundation into a functional assay requires even deeper physiological insight. For example, accurate quantification of insulin depends on an in-depth understanding of hepatic clearance, receptor-binding kinetics, and molecular half-life; these factors all influence the sensitivity, specificity, and reference intervals of an assay. With the FDA’s premarket review requirement rescinded, laboratories now rely on their scientific expertise and compliance with CLIA accreditation standards and proficiency testing to ensure every assay accurately reflects the underlying biology.

Designing an assay is only half the battle; managing a collected sample is equally critical, as it represents a biological balancing act that goes beyond test design. If blood sits at room temperature for too long, proteins can degrade, pH can shift, and cells may rupture—potentially altering test results before analysis even begins. Previously, these variables were managed under uniform FDA protocols. Now, in the absence of FDA oversight, laboratories will be responsible for ensuring their processes are accurate and adhere to CLIA standards. That makes understanding physiology even more critical, especially since different labs may handle samples in slightly different ways. To ensure that results are accurate and truly reflect the patient’s sample without being affected by handling or testing, labs must maintain regular training, thorough documentation, and continuous monitoring of these biological factors.

Looking ahead, LDTs are becoming more sophisticated by incorporating cell-free DNA sequencing, microbiome metabolite profiling, and pharmacogenomic variants that alter drug metabolism. Applying physiological principles to test design, validation, and sample handling by labs and clinicians is essential to their reliability. With oversight under CLIA rather than FDA premarket review, the lab community, supported by accreditation and proficiency testing, bears responsibility for ensuring each assay truly reflects the underlying biology. Any future regulatory framework should build on this foundation by aligning policy with molecular science to foster ongoing innovation while safeguarding test accuracy and patient safety.