In our blog in December 2024, we provided an update on the U.S. Food and Drug Administration (FDA) final rule, revising the regulatory definition of an in vitro diagnostic (IVD) to explicitly capture IVDs manufactured by laboratories (known as laboratory developed tests or LDTs). We noted that two cases had been filed challenging the FDA’s authority to regulate LDTs.

On March 31, 2025, the Eastern District of Texas granted the laboratory plaintiffs’ motions for summary judgment and vacated the FDA’s LDT Final Rule, ruling in favor of the American Clinical Laboratory Association (ACLA) and the Association for Molecular Pathology (AMP). The ruling was widely anticipated and is among the first challenges to FDA rulemaking decided post-Loper Bright. In rejecting the final rule, the court agreed with ACLA and AMP that laboratory-developed tests are services, not devices.

Read our Advisory for details on this ruling.