A federal court struck down the FDA’s final rule to regulate lab‑developed tests (LDTs), marking a major legal reversal for the agency and reshaping diagnostics oversight in 2025. The decision halted a high‑profile rulemaking effort and signaled judicial limits on FDA’s expansion into laboratory testing. The ruling amplifies uncertainty for stakeholders pursuing diagnostic approvals and complicates ongoing policy discussions about oversight of AI‑driven diagnostics. Companies, laboratories, and regulators now face a fragmented compliance environment while appeals and alternate legislative options play out.