Understanding the March 2025 Court Ruling Regarding LDT Regulation by the FDA

On March 31, 2025, the U.S. District Court for the Eastern District of Texas issued a landmark ruling that vacated the FDA's Final Rule on Laboratory Developed Tests (LDTs). This decision has significantly positive implications for labs that frequently use LDTs as a part of their workflows.

Why Over-Regulation of LDTs Matters

LDTs have long played a vital role in the evolution of diagnostic medicine. While commercial test kits support a variety of clinical diagnostic tests, they are required to go through the FDA’s traditional premarket review process. LDTs serve as an alternative that allows labs to flexibly respond to emerging or contextual clinical needs, and have historically had a regulatory compliance structure that is designed with this in mind.

Before the FDA's attempt to assert regulatory authority, LDTs were—and now, following the recent ruling, continue to be—regulated under the Clinical Laboratory Improvement Amendments (CLIA) by the Centers for Medicare & Medicaid Services (CMS), not the FDA. This regulatory framework has enabled many certified labs across the country to develop high-quality tests quickly and responsibly—especially when no FDA-approved options exist.

Over-regulation of LDTs can have significant impacts on labs that rely on them for:

• Rapid Innovation: LDTs allow laboratories to develop new tests much faster than the FDA’s slow approval process allows. This specific advantage often only becomes obvious when 
  public health emergencies or new diseases emerge.
  
  
• Personalized Medicine: Specialty areas of medicine like oncology, genetics, and infectious disease use LDTs to create tailored testing for specific patient populations or rare
  conditions that commercial developers often don’t prioritize.
  
  
• Filling Gaps in Test Availability: Many rare disease diagnostic tests are only available as
  LDTs because they serve a small enough patient population that FDA-cleared commercial
  versions don’t exist.
  
  
• Support for Niche and Local Needs: LDTs allow laboratories to meet the unique health concerns of their specific communities, whether through region-specific infectious disease 
  testing or emerging variants.

Implications of the Court's Decision

The court's ruling puts a block on the FDA's efforts to regulate LDTs as in vitro diagnostic products (IVDs). This decision is seen as a victory for laboratories concerned about the potential burdens of additional FDA regulation.​

Many industry experts thought that the FDA’s interventions would complicate compliance, slow innovation, raise costs, and restrict patient access to critical diagnostics—especially in areas where FDA-approved tests are unavailable or too generalized to be useful. As such, the recent court ruling preserves the ability to continue offering validated and timely diagnostic tests without undue additional regulatory burden.

On What Grounds Was the FDA Final Rule Vacated?

As noted in the court’s opinion, “the text, structure, and history of the FDCA and CLIA make clear that FDA lacks the authority to regulate laboratory-developed test services.” The opinion elaborates that Congress specifically chose to regulate clinical laboratories and their services separately through CLIA, rather than through the FDA.

Timeline of Key Events in LDT Regulation

• October 2023: The FDA publishes a proposed rule to phase out its enforcement discretion
  over LDTs, aiming to regulate them as IVDs.
  
  
• May 2024: The FDA issues its Final Rule, outlining a phased approach to regulate LDTs 
  under the Federal Food, Drug, and Cosmetic Act (FDCA).
  
  
• August 2024: The Association for Molecular Pathology (AMP) files a lawsuit challenging 
  the FDA's authority to regulate LDTs as medical devices.
  
  
• March 2025: Judge Sean D. Jordan rules that the FDA exceeded its statutory authority, 
  vacating the Final Rule in its entirety and remanding the matter to the Secretary of Health 
  and Human Services (HHS).

Key Voices From the Industry

After the victory, presidents of major laboratory organizations celebrated the court’s ruling:

• Jane S. Gibson, President of The Association of Molecular Pathology (the group 
  responsible for bringing the lawsuit) commented in a press release, “AMP is extremely pleased with the court’s clear and decisive ruling in our favor, and we hope this will finally end 
  the FDA’s attempts to exert an unwarranted overreach of authority of LDTs.”
• Susan Van Meter, President of the American Clinical Laboratory Association commented, “The court’s ruling ensures that clinical laboratories can continue to focus on their primary mission – offering innovative and reliable diagnostics that save and improve the lives of 
  millions of patients every day. This is a victory that protects patient access to critically 
  needed testing services and removes burdensome regulations that would have undermined the clinical laboratory system in this country.”
• Donald Karcher MD, FCAP, President of the College of American Pathologists, commented, “The FDA's LDT rulemaking was burdensome, and the court rightly struck it down. 
  The regulation failed to target FDA oversight and threatened patient access to countless 
  numbers of safe LDTs by saddling laboratories with unnecessary requirements. The CAP 
  and its members are relieved that the court agreed with our arguments.”

What Happens Next?

As it stands, the FDA exerts no regulatory oversight over LDTs, meaning CMS’ CLIA regulatory standards will continue to govern matters related to LDT compliance. However, the matter has been remanded to the Secretary of Health and Human Services (HHS), so future regulatory efforts cannot be ruled out—whether through new rulemaking, legislative proposals, or legal appeals. At the time of writing, the FDA has not publicly indicated if it intends to appeal the decision, but we are continuing to monitor the situation closely.

Streamline Scientific: With Your Lab Through It All

Streamline Scientific stands with industry experts and labs nationwide to fully support this decision, which aligns with our goals of supporting laboratories in delivering high-quality molecular diagnostic services through streamlined processes and innovative solutions. This ruling will help maintain access to vital testing services while allowing laboratories to focus on improving patient care.

Laboratory regulatory oversight is an ever-changing landscape, and keeping up with it can be a challenge. We remain committed to supporting our laboratory partners by keeping them abreast of regulatory changes. If you have questions about how this ruling may affect your laboratory operations, please contact our team of specialists.​

Follow the link if you are interested to see the court’s full memorandum opinion and order, as published by the ACLA.