Diagnostics

Diagnostic Tests are Generally Regulated as Devices

The Federal Food, Drug, and Cosmetic Act’s (FDCA’s) definition of “device” includes “in vitro reagent” that “is intended for use in the diagnosis of a disease or other conditions . . . .” Thus, in vitro diagnostic products (IVDs) are considered devices under the FDCA, and are generally subject to FDA’s premarket and postmarket requirements, including clearance or approval, quality controls for manufacturing and distribution, and specific labeling requirements. Many genetic tests are IVDs, as are tests used in genomics, personalized medicine, and with digital health technologies to identify whether a patient is likely to benefit from a particular treatment.

FDA generally regulates IVDs according to the agency’s device risk classification system: ranging from Class I to Class III, the higher the device classification, the more FDA regulations the developer/manufacturer must follow, and the longer the statutory timeline for the device to be legally marketed. As clinical laboratory tests, IVDs are also subject to requirements and categorization under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), which is administered and enforced by the Centers for Medicare & Medicaid Services (CMS).

LDTs are Distinct from IVDs

Laboratory developed tests (LDTs) have long been distinguished from IVDs because of differences in development, implementation, and use. IVDs are diagnostic tests that manufacturers sell and distribute to laboratories as complete “kits,” and come with all components – reagents, controls, and procedures – that a laboratory needs to perform the test. LDTs are designed, manufactured, and performed entirely within a single laboratory. This distinction presents an important legal and jurisdictional issue.

FDA first asserted that LDTs were devices subject to its jurisdiction in 1992. Faced with numerous challenges to this authority, the agency spent more than 30 years largely exercising “enforcement discretion” over LDTs. This created years of confusion and uncertainty for the laboratory industry. (For Penn Avenue Law & Policy’s detailed analysis of the history of FDA’s attempt to regulate LDTs, see here and here).

On May 6, 2024, FDA published a final rule in the Federal Register that amended the definition of IVDs to explicitly include tests “manufactured” in a laboratory. This change formally subjected LDTs to FDA regulation as medical devices. Under the final rule, FDA planned to phase out its longstanding practice of enforcement discretion for LDTs with a five-stage policy over the course of four years. Because the burdens on laboratories to comply with FDA’s device regulations are costly and confusing, the final rule was projected to stifle innovation, drastically reduce the availability of tests, and lead to a consolidation of the laboratory industry.

A Recent Court Ruling Determined LDTs are not Devices

The American Clinical Laboratory Association (ACLA) and the Association for Molecular Pathology (AMP) both sued FDA, and claimed that in publishing the final rule, the agency exceeded its statutory authority and violated the Administrative Procedures Act (APA). Both plaintiffs asserted that LDTs do not fall under the FDCA’s definition of device and asked the court to (1) declare FDA does not have authority to regulate LDTs as devices, (2) vacate the LDT final rule, and (3) enjoin FDA from enforcing the final rule.

ACLA’s and AMP’s cases were consolidated, and oral argument was heard by the Honorable Sean D. Jordan, United States district judge of the United States District Court for the Eastern District of Texas on February 19, 2025. Judge Jordan agreed with the plaintiffs’ arguments, and on March 31, 2025, vacated and set aside the final rule and remanded the matter back to the Secretary of Health and Human Services for further consideration. The government did not appeal Judge Jordan’s decision.

A summary of Judge Jordan’s decision can be found here. In brief, the court determined that LDTs are not devices and that the final rule violates the APA because it exceeds FDA’s statutory jurisdiction. The court explained that the definition of device under the FDCA applies to tangible, physical products introduced into interstate commerce. LDTs are laboratory services that, like all professional medical services, are qualitatively and categorically different from tangible goods that can be regulated by FDA. Moreover, the timelines and legislative histories of the FDCA and CLIA show that Congress viewed laboratory tests as distinct from devices. Thus, FDA’s attempt to expand its device jurisdiction over LDTs is foreclosed by the text, structure, and history of the FDCA and CLIA, and violates the APA.

Legislative Changes are Needed

There are many short- and long-term implications of the court’s ruling. The debate over the appropriate regulation for LDTs has been raging for more than 30 years, and though the government did not appeal the district court’s decision, it is not the end of the story. As discussed here and here, members of both the House and the Senate have resumed dialogue about alternative regulatory classifications and systems for laboratory tests. There are opportunities for laboratories to engage with Congress and other stakeholders to potentially enact new legislation that would be less burdensome and better support innovation.

All Laboratories Must Comply with CLIA Requirements

Through CLIA, CMS regulates all non-research laboratory tests performed on humans in the United States. Before a laboratory can accept human specimens for testing, it must have CLIA certification. CLIA certificates vary based on the types and complexities of tests performed by the laboratory.

CMS’ objective under CLIA is to ensure that laboratories performing tests on human specimens produce accurate and reliable test results. Under the FDCA, FDA regulates devices, including IVDs, to ensure that they are reasonably safe and effective. Laboratories manufacturing IVDs or developing LDTs must be aware of and comply with applicable CLIA requirements.

Christine P. Bump has Extensive Experience Regarding the Regulation of Diagnostic Tests

There remains a lot of confusion regarding the regulation of diagnostic tests, and how laboratories consistently comply with both FDA requirements and CLIA. Whether your test is an IVD device, an LDT, or being combined with a personalized medicine/digital health technology, you need legal counsel who is experienced at navigating these pathways. Christine P. Bump has extensive experience advising clients on the regulations, guidance, and policies applicable to laboratories and tests, and developing regulatory strategies for diagnostic tests, even when pathways are not clearly defined.