The U.S. Food and Drug Administration (FDA) has announced a landmark final rule that brings laboratory-developed tests (LDTs) under its regulatory oversight, marking a fundamental shift in how these diagnostic tools are regulated in the United States.
Scope and Implementation
The new regulation explicitly classifies in vitro diagnostics (IVDs) as medical devices under the Federal Food, Drug, and Cosmetic Act, regardless of whether they are manufactured by laboratories or traditional device makers. This change affects tests used for various critical medical purposes, including newborn screening, cancer risk assessment, and diagnosis of cardiac conditions and neurological disorders.
FDA Commissioner Robert Califf, MD, emphasized the necessity of this change: "LDTs are being used more widely than ever before... The agency cannot stand by while Americans continue to rely on results of these tests without assurance that they work."
Transition and Enforcement
The final rule establishes a 4-year phase-out period for the FDA's previous enforcement discretion approach. Jeff Shuren, MD, JD, director of the FDA's Center for Devices and Radiological Health, explained that this timeline was influenced by public comments on the proposed rule. The agency will maintain discretionary oversight for:
- LDTs marketed before the final rule's issuance
- Tests addressing unmet medical needs
- LDTs approved by New York State's Clinical Laboratory Evaluation Program
Safety Concerns and Evidence
The FDA's decision is supported by mounting evidence of public health concerns related to some LDTs. According to Dr. Shuren, research, FDA reviews, news reports, and class-action lawsuits have revealed instances where LDTs provided inaccurate results or underperformed compared to FDA-authorized tests.
Industry Response and Concerns
The regulatory change has sparked diverse reactions from stakeholders. Diana Zuckerman, PhD, of the National Center for Health Research, supported the increased oversight but expressed concern about grandfathering existing tests: "Unfortunately, this final rule has compromised on a crucial issue: it 'grandfathers' the thousands of tests -- some dangerously inaccurate -- that are already on the market."
Industry representatives and some lawmakers have raised concerns about potential impacts on healthcare accessibility and costs. Rep. Cathy McMorris Rodgers argued that the rule "will still increase costs and decrease access to diagnostics and medical tests that provide information crucial for doctors to treat their patients effectively."
Emergency Provisions
The FDA has also issued two draft guidances addressing emergency situations:
- Enforcement discretion for IVDs needed in emergent situations like infectious disease outbreaks
- Guidelines for enforcement policies during public health emergencies
Historical Context
Previously, LDTs were primarily overseen through the Clinical Laboratory Improvement Amendments of 1988 (CLIA) and regulated by the Centers for Medicare & Medicaid Services. This system did not require demonstration of clinical validity, a gap the new FDA regulation aims to address.
Patient advocacy groups have largely welcomed the change. Patricia Kelmar of U.S. PIRG praised the FDA's approach, noting that it prioritizes patient safety by requiring test developers to demonstrate accuracy and clinical reliability before patient use.
