Laboratory developed tests part 2

Oct. 18, 2023

On October 3, 2023, the Food and Drug Administration (FDA) published its anticipated proposed rule to regulate laboratory developed tests (LDTs) as medical devices.1 The proposed rule changes the definition of in vitro diagnostic products (IVDs) at 21 CFR 809.3(a) with the underlined text below.

In vitro diagnostic products are those reagents, instruments, and systems intended for use in the diagnosis of disease or other conditions, including a determination of the state of health, in order to cure, mitigate, treat, or prevent disease or its sequelae. Such products are intended for use in the collection, preparation, and examination of specimens taken from the human body. These products are devices as defined in section 201(h) of the Federal Food, Drug, and Cosmetic Act (the act), and may also be biological products subject to section 351 of the Public Health Service Act, including when the manufacturer of these products is a laboratory.

The FDA is proposing “to gradually phase out its current general enforcement discretion approach so that most IVDs offered as LDTs would generally fall under the same enforcement approach as other IVDs.” The new enforcement policy, as proposed, would be implemented in five phases summarized as follows:

1.    End the FDA’s general enforcement discretion related to medical device reporting (MDR) requirements and correction and removal reporting requirements. FDA would make this change one year after it publishes a final phaseout policy, which it intends to issue in the preamble of the final rule.

2.     Begin enforcing registration and listing requirements, labeling requirements, and investigational use (IDE) requirements two years after the final phaseout policy is published.

3.     End the general enforcement discretion approach with respect to quality system (QS) requirements (with a complementary approach with CLIA’s QS requirements for LDTs manufactured within a single CLIA-certified laboratory and not distributed outside that laboratory) three years after the FDA publishes a final phaseout policy.

4.     Submission of premarket approval (PMA) applications for high-risk IVDs (i.e., class III devices) 3.5 years after final phaseout policy is published, but no earlier than October 1, 2027.

5.     End the general enforcement discretion approach with respect to premarket review requirements for moderate-risk and low-risk IVDs (that require premarket submissions) four years after final phaseout policy is published, but not before April 1, 2028.

Comments on this proposed rule must be submitted by December 4. For anyone interested in reading comments submitted electronically, they can be viewed at

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


1.     Food and Drug Administration. Medical devices; Laboratory developed tests. Federal Register. 2023;88:68006-68031.