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The Future Regulation of Laboratory-Developed Tests (LDTs)

This post is part of a two-part series. You can read Part 2 here.

Per the FDA commissioner, Dr. Robert M. Califf, and data from the Center of Disease Control (CDC), 70% of medical decisions depend on laboratory test results. Do you consider this significant enough for FDA regulation? Well, spoiler, they do.

On September 29, 2023, the FDA announced its proposed rule that will include LDT’s in the scope of their regulations as a Medical Device – hereby bound to 21 CFR Part 820, 510(k) submissions, and PMA pathways (as applicable). The FDA took their first shot at regulating LDTs in 2014 with a draft guidance that ultimately never made its way to approval.

What are LTDs?

Laboratory-Developed Tests (LDTs) are diagnostic tests that are developed, validated and performed by a single clinical laboratory for the purpose of assessing specific medical conditions or diseases. They are often referred to as “in-house tests” since they are not commercially manufactured and distributed like standard diagnostics tests. LDTs serve several key purposes in healthcare and diagnostics.

This leeway allows laboratories to tailor tests to their patient populations, target specific medical conditions, diagnose and monitor rare diseases, aid in early detection of emerging pathogens and containment efforts, assess biomarkers and gene markers, study disease progression in clinical trials, and close diagnostics gaps caused by commercially available tests. This list only scratches the surface of clinical benefits of LDT’s and how they are constantly advancing diagnostics.

An important note is that LDT’s are currently regulated, just not by the FDA. The Centers for Medicare & Medicaid Services (CMS) has regulated laboratories, including those that develop LDTs, under the Clinical Laboratory Improvement Amendments since 1988. CLIA governs the accreditation, inspection, and certification process for laboratories. While CLIA oversight is important, it alone does not ensure that LDTs are properly designed, consistently manufactured, and are safe and effective for patients.

Risks of Modern LTDs

The risk with modern LDT’s is much steeper than it used to be decades ago. The scale of LDTs historically was much smaller; however, with advancing technology and increasing demand, the market has grown exponentially. The FDA is concerned with misleading results that lead to unnecessary treatment and harm to patients. Premarket review would ensure that LDTs are properly designed and evaluated for analytical and clinical validity in the intended use population, two critical aspects of IVD performance.

The proposed rule will be open for comments between October 2, 2023 and December 1, 2023 under docket number FDA-2023-N-2177. Look to Rook for the most up-to-date information on the proposed ruling, and for future implementation strategies if this affects your business.

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