FDA to Delay Enforcement of New Lab-Developed Test Rules by 90 Days, Pushing Start to May 6

The Delayed Enforcement Date

The Food and Drug Administration will delay enforcement of new regulations governing laboratory-developed tests by 90 days, pushing the first compliance deadline from Feb. 4 to May 6, according to two FDA officials familiar with the rule. The officials said the delay will apply to the initial phase of the rule, which requires high-complexity clinical laboratories to register with the FDA and list the tests they market directly to consumers or physicians. The rule, finalized in April 2024, was scheduled to take full effect over a four-year period ending in 2028.

The officials said FDA Commissioner Marty Makary informed senior staff of the decision during a Jan. 6 meeting at the FDA's White Oak campus in Silver Spring, Maryland. One official said the agency plans to publish a guidance document on Jan. 8 explaining which tests will be exempt from the initial enforcement window. The second official said the delay is a direct response to concerns raised by hospital laboratories, academic medical centers, and industry groups about their ability to meet the Feb. 4 deadline.

One FDA official said the agency will post a revised compliance timeline on its website by Jan. 9. The official said laboratories that have already submitted registration materials will not need to resubmit but should expect a revised acknowledgment letter. The second official said the Office of Regulatory Affairs will direct field staff to hold off on any inspections related to the initial registration requirement until after May 6.

Industry Pressure and Costs

A lobbyist for device makers said the delay represents a partial victory for diagnostic companies that have argued the FDA underestimated the cost and complexity of bringing thousands of tests into compliance. The lobbyist, who represents members of the Advanced Medical Technology Association and the American Clinical Laboratory Association, said industry estimates place the total compliance cost at approximately $3.2 billion over four years. The lobbyist said device makers remain concerned that the FDA will still require adverse event reporting for certain tests beginning in May, which could force smaller labs to withdraw tests from the market.

The lobbyist said one member company spent $11 million in 2025 preparing quality management systems for the rule and had budgeted an additional $8 million for 2026. The lobbyist said the 90-day delay will allow the company to redirect some of that spending toward clinical validation studies but will not change the overall compliance burden. The lobbyist said AdvaMed plans to send a letter to the FDA on Jan. 9 requesting additional clarity on adverse event reporting obligations.

A hospital administrator briefed on the rule said the delay gives academic medical centers additional time to validate tests for rare diseases and oncology. The administrator, who oversees laboratory operations at a 950-bed teaching hospital in the Midwest, said the hospital operates roughly 180 laboratory-developed tests and had budgeted $4.7 million for compliance in 2026. The administrator said the 90-day extension will allow the hospital to complete validation studies for 22 tests that were at risk of being discontinued if the Feb. 4 deadline had held.

Rule Background and Scope

The laboratory-developed test rule reverses decades of FDA policy under which the agency generally exercised enforcement discretion for tests designed and used within a single laboratory. The April 2024 final rule requires laboratories to comply with medical device regulations, including quality system requirements, premarket review for high-risk tests, and adverse event reporting. The rule affects an estimated 12,000 laboratories nationwide, including hospital labs, commercial reference laboratories, and direct-to-consumer testing companies.

The two FDA officials said the delayed enforcement does not change the underlying rule or the final 2028 compliance deadline. One official said the agency will use the additional 90 days to finalize a template for laboratory registration and to train field investigators on inspection protocols. The second official said the FDA Office of In Vitro Diagnostics and Radiological Health has scheduled three webinars in late January to explain the guidance to stakeholders, with the first session planned for Jan. 21 at 1 p.m. Eastern time.

The rule has faced legal challenges since its publication. The Association for Molecular Pathology filed a lawsuit in the U.S. District Court for the District of Columbia arguing the FDA lacks statutory authority to regulate laboratory-developed tests as medical devices. A federal judge denied a preliminary injunction in August 2025 but allowed the case to proceed. The FDA officials said the agency does not view the 90-day delay as a concession in that litigation.

What to Watch Next

Three developments in the next 48 to 72 hours will clarify how laboratories should prepare. First, the Jan. 8 guidance document will detail the scope of the enforcement delay and any new documentation requirements. Second, the House Energy and Commerce Committee is expected to announce a hearing on diagnostic regulation for the week of Jan. 26, where Makary may testify. Third, the D.C. district court could issue a scheduling order in the Association for Molecular Pathology case that shapes how the delay affects the parties' arguments.

The two FDA officials said the agency remains committed to full implementation of the rule but wants to avoid disruptions to testing for cancer, genetic disorders, and infectious diseases. The lobbyist for device makers said larger diagnostic manufacturers view the delay as an opportunity to gain market share if smaller hospital labs exit certain testing areas. The hospital administrator said the next 72 hours will determine whether the 90-day reprieve is long enough to save tests that serve patient populations with few alternatives.