The LDT regulatory landscape changed materially in 2025. A federal district court vacated FDA's May 2024 final rule on March 31, 2025. FDA later issued a final rule on September 19, 2025 that reverted the definition text to the version in place before the vacated rule. The staged phaseout framework from the 2024 rule should therefore not be presented as the current governing timeline.
What the 2024 final rule attempted to change
The 2024 rule amended the regulatory definition of in vitro diagnostic products by adding language addressing when the manufacturer is a laboratory. It also described a staged approach to ending general enforcement discretion for many IVDs offered as LDTs.
What the court did in March 2025
The federal district court vacated the final rule. Vacatur removed the rule rather than merely postponing one compliance date. Organizations that created content, roadmaps, or product claims around the phaseout schedule should review and update those materials.
What FDA did in September 2025
FDA states that it issued a final rule reverting the regulatory text to the wording that existed before the effective date of the May 2024 rule. FDA's current LDT page should be treated as the primary reference for the status of that rulemaking.
What did not disappear: CLIA oversight
CMS continues to regulate laboratory testing performed on humans in the United States through CLIA, except research testing. CLIA addresses laboratory quality, personnel, procedures, and reliable patient results. The exact obligations of a laboratory depend on its testing and circumstances.
What this means for PCR reagent suppliers
A reagent development or manufacturing supplier should accurately describe the supplied material and avoid implying that a custom reagent is a cleared, approved, or independently validated clinical product. The laboratory and supplier should maintain a clear responsibility boundary.
Use current sources for current decisions
Regulatory status can change through legislation, rulemaking, guidance, litigation, or agency action. This article is an informational summary, not legal or regulatory advice. Laboratories should verify the current official position and consult qualified advisors for their specific pathway.