The U.S. Food and Drug Administration (FDA or Agency) announced on April 29, 2024, in a forthcoming and long-awaited final rule that laboratory developed tests (LDTs) will be regulated as medical devices.

LDTs are in vitro diagnostic products (IVDs) that are intended for clinical use and designed, manufactured and used within a single clinical laboratory that meets certain regulatory requirements. Currently, FDA regulates most of these tests using its enforcement discretion authority, and therefore the Agency has generally not enforced applicable FDA requirements such as premarket clearance and establishment registration. FDA's enforcement policy on LDTs was established "many decades ago," however, in recent years the Agency has stressed that the risks associated with most modern LDTs are much greater than the risks that were associated with LDTs used previously.

The final rule, scheduled to be published on May 6, 2024, amends the Federal Food, Drug and Cosmetic Act (FDCA) to include LTDs within the definition of a medical device. LDTs being regulated as medical devices subjects the LDT manufacturer to medical device requirements such as premarket review, quality system requirements, adverse event reporting, establishment registration and device listing, labeling requirements and investigational use requirements.

FDA plans to use a "phaseout policy" to transition currently marketed LDTs to regulated medical devices. The phaseout policy will be in five stages and is set forth below:

• Stage 1. Beginning on May 6, 2025, which is one year after the publication date of the final LDT rule, FDA will expect compliance with medical device reporting (MDR) requirements, correction and removal reporting requirements, and QS requirements regarding complaint files.
• Stage 2. Beginning on May 6, 2026, which is two years after the publication date of the final LDT rule, FDA will expect compliance with requirements not covered during other stages of the phaseout policy, including registration and listing requirements, labeling requirements and investigational use requirements.
• Stage 3. Beginning on May 6, 2027, which is three years after the publication date of the final LDT rule, FDA will expect compliance with QS requirements (other than requirements regarding complaint files which are already addressed in Stage 1).
• Stage 4. Beginning on Nov. 6, 2027, which is 3½ years after the publication date of the final LDT rule, FDA will expect compliance with premarket review requirements for high-risk IVDs offered as LDTs (IVDs that may be classified into Class III or that are subject to licensure under Section 351 of the Public Health Service Act), unless a premarket submission has been received by the beginning of this stage in which case FDA intends to continue to exercise enforcement discretion for the pendency of its review.
• Stage 5. Beginning on May 6, 2028, which is four years after the publication date of the final LDT rule, FDA will expect compliance with premarket review requirements for moderate-risk and low-risk IVDs offered as LDTs (that require premarket submissions), unless a premarket submission has been received by the beginning of this stage in which case FDA intends to continue to exercise enforcement discretion for the pendency of its review available.

Additional guidance and details are expected on these issues. FDA intends to hold a webinar on May 14, 2024, to provide an overview of the final rule and phaseout policy. Holland & Knight will provide details when they become available.

The authors are monitoring the many new requirements imposed under the regulation and are able to assist any LDT manufacturers with questions as they seek to achieve regulatory compliance.