A First Step? Reclassification of High-Risk LDTs Assists FDA with Oversight of LDTs

February 09, 2024

The US Food and Drug Administration’s (FDA’s) Center for Devices and Radiological Health recently announced its intention to reclassify certain high-risk in vitro diagnostic devices (IVDs) as moderate risk, a potential first step as the agency prepares to oversee laboratory-developed tests (LDTs).

On January 31, 2024, the FDA announced via press release a pivotal shift in its regulatory oversight for IVDs. Specifically, the FDA intends to reclassify most Class III (high risk) IVDs, which are generally infectious disease and companion diagnostic IVDs, into Class II (moderate risk).

The reclassification process will result in manufacturers seeking to market IVDs introduced after the reclassification being able to submit 510(k) premarket applications to demonstrate substantial equivalence, as opposed to the more rigorous premarket approval (PMA) application requiring a demonstration that the product is safe and effective (which includes preapproval inspections of facilities).

This regulatory shift appears to be part of the FDA’s broader action plan in preparing to remove enforcement discretion previously offered to LDTs, thus resulting in LDTs having to fully comply with the Federal Food, Drug, and Cosmetic Act.

As we previously wrote, the FDA issued a proposed rule for a four-year phaseout of its enforcement discretion for LDTs, and the final rule is expected to be published in April 2024. Under the proposed rulemaking, LDTs that would be Class III (high risk) IVDs would require PMA application acceptance no later than 3.5 years after the final rule’s publication.

The FDA’s new proposal to reclassify Class III IVDs into Class II would significantly reduce the application burden on manufacturers seeking FDA authorization of LDTs and thus minimize the impact of the FDA’s revocation of its enforcement discretion.

For example, in addition to data demonstrating safety and effectiveness (which usually include clinical data), PMA applications require a description of the manufacturing process. Once a PMA is approved, manufacturers must seek FDA approval before implementing certain changes. By contrast, 510(k) premarket applications only require data to demonstrate substantial equivalence to the legally marketed predicate (which usually do not include clinical data). Moreover, there are no preclearance inspections of manufacturers, and only changes that could significantly impact safety or effectiveness require preauthorization from the FDA.

The FDA’s strategic move is not only a regulatory adjustment but also a response to the evolving landscape of diagnostic testing, reflecting advances in technology and the agency’s better understanding of these devices’ risk profiles.


Morgan Lewis guides and provides strategic counseling to IVD manufacturers and laboratories on bringing novel technologies to market utilizing the least burdensome FDA regulatory approach. Morgan Lewis lawyers prepare marketing applications (e.g., EUA, 510(k), De Novo) and interact with the FDA to help ensure timely review and authorization of applications.


If you have any questions or would like more information on the issues discussed in this LawFlash, please contact any of the following:

Dennis C. Gucciardo (Washington, DC)
Michele L. Buenafe (Washington, DC)
Maria Kalousi-Tatum (Washington, DC)