Laboratory developed tests

Sept. 21, 2023

In the spring 2023 Unified Agenda, published this past June in the Federal Register, The U.S. Food and Drug Administration (FDA) announced its plan to release a proposed rule in August 2023 that would change the way that the agency regulates laboratory developed tests (LDTs) by amending the FDA’s regulations to make explicit that laboratory developed tests (LDTs) are devices under the Federal Food, Drug, and Cosmetic Act. The Unified Agenda provides information on regulatory and deregulatory activities under development throughout the federal government. The August date was an anticipated date and isn’t binding. As of this writing, the proposed rule still hasn’t been published.

For those who may not be familiar with the rulemaking process, a proposed rule is a preliminary version of a prospective federal agency regulation(s). During the proposed rule process, a federal agency seeks public comment (usually for 60 days) on its preliminary version of regulatory changes. The agency, the FDA in this case, might take these comments into account before finalizing regulatory changes and issuing the final rule.

Per the FDA, LDTs are a class of in vitro diagnostic (IVD) devices that are designed, manufactured, and used within a single laboratory. LDTs are often used to test for conditions or diseases that are either rapidly changing (e.g., new strains of known infectious diseases) or are the subject of advancing scientific research (e.g., genomic testing for cancer). It is presumed that the proposed rule would add a clause or section within the FDA’s IVD regulations (21 CFR 809) that would specify that LDTs are a kind of IVD, and therefore a medical device.

Since 2018, Congress has made attempts to address LDT regulation through the Verifying Accurate, Leading-Edge IVCT Development (VALID) Act. In December 2022, the VALID Act was included in the year-end omnibus spending package, but it was ultimately cut out. It looks like the FDA is going forward since Congress did not.    

In recent years, the FDA has indicated its intent to regulate LDTs using a risk-based, phased-in approach due to the increasing number, significance, and complexity of LDTs. In January 2017, the FDA issued a discussion paper with a proposed framework for LDT oversight that would focus on “new and significantly modified high and moderate risk LDTs.”1 Previously marketed LDTs would be grandfathered and would not be expected to comply with most or all FDA regulatory requirements, such as premarket review, quality systems, and registration unless necessary to protect the public health. This discussion paper was a follow-up to draft guidance the FDA published in 2014 where it received numerous comments from a broad range of stakeholders. This paper may still provide insight into the direction of the proposed rule, but what will be handled in law and what will be in guidance is unclear.

For readers interested in regulatory updates pertaining to clinical laboratories, our daily LABline e-newsletter provides updates, when available. When the FDA proposed rule is published, we will announce it there. You can sign up for LABline here:

I welcome your comments and questions — please send them to me at [email protected].


1. Discussion paper on laboratory developed tests (LDTs). Published 2017. Accessed September 11, 2023.