What is the role of CLIA in LDTs after the FDA's rule?

CLIA continues to regulate the analytical and clinical validity, as well as the overall quality of laboratory testing. The FDA’s new rule focuses on the safety and effectiveness of the LDTs as medical devices. CLIA regulations will remain critical for ensuring the operational quality of the laboratory itself.

Are there specific types of LDTs that may be exempt from the new FDA regulations?

The final rule outlines certain exemptions and enforcement discretion policies for specific categories of LDTs, such as those for rare diseases or for use in public health emergencies, though these are limited and subject to specific criteria. Laboratories should consult the final rule and FDA guidance for precise details on exemptions.

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Market SegmentsStrategic LandscapeLDT

Laboratory-Developed Test

IVD designed, manufactured, and used within a single CLIA laboratory.

Reviewed by Christian Espinosa, Founder, Blue Goat CyberLast reviewed May 5, 2026

Definition

LDTs are diagnostic tests developed and performed by a single high-complexity CLIA-certified laboratory rather than distributed as kits. FDA historically exercised enforcement discretion; a 2024 final rule began phasing in active oversight. FDA issued a rule in 2024 to phase in oversight of LDTs, but a federal court vacated it in March 2025, so LDTs remain primarily under CLIA. Laboratories must still validate performance and meet CLIA quality rules. In the EU, health institution exemptions under IVDR Article 5(5) play a similar role with strict conditions.

What the regulation says

The FDA, under the Medical Device Amendments of 1976 to the Food, Drug, and Cosmetic Act, has the authority to regulate in vitro diagnostics (IVDs), which include Laboratory-Developed Tests (LDTs). While the FDA historically exercised enforcement discretion, the Medical Device User Fee Amendments of 2022 (MDUFA V) included provisions setting the stage for increased FDA oversight of LDTs. The Clinical Laboratory Improvement Amendments (CLIA) of 1988, administered by CMS, regulate the quality of laboratory testing regardless of where tests are performed, ensuring accuracy, reliability, and timeliness of patient test results.

What this means in practice

Many oncology, infectious disease, and rare-disease tests reached patients as LDTs. The FDA LDT rule, ongoing litigation, and CMS PAMA repricing are key uncertainties.

Examples

A hospital laboratory develops a novel genetic test for a rare inherited condition, performing all aspects of the test in-house with CLIA certification.
A commercial reference laboratory creates a new diagnostic assay for a difficult-to-culture infectious agent, offering it to healthcare providers as a service.
A university research lab validates a personalized diagnostic test to predict therapeutic response for specific cancer patients, adhering to CLIA standards for its operational processes.

Common pitfalls

•A key misconception is that CLIA certification alone is sufficient for regulatory compliance of an LDT.
•Some assume that all LDTs are exempt from FDA regulation, which is no longer the case with the implementation of new oversight.
•Neglecting to consider the phased implementation schedule of the FDA’s new LDT rule can lead to significant compliance gaps.

Frequently asked questions

The FDA's new rule is expected to phase in requirements for LDTs, potentially subjecting them to the same regulatory requirements as other in vitro diagnostics, including premarket review, quality system regulations, and adverse event reporting. The specific impact will depend on the phase and type of LDT, with a transition period provided for laboratories to meet the new standards.

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Regulations or standards this term must comply with.

Clinical Laboratory Improvement Amendments(CLIA)

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Clinical Laboratory Improvement Amendments(CLIA)

U.S. federal standards that govern clinical laboratory testing.

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In Vitro Diagnostics(IVD)

Tests performed on biological samples outside the body.

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Sources

3 sources

Every citation below opens the original document. Each is graded against our source-tier hierarchy so you can see what rests on binding law versus commentary.

Tier 2Regulator guidance and consensus· 1Tier 4Trade press and expert commentary· 2

Link health: 3 verified· last checked 2026-06-20

FDA·1AdvaMed·1MedTech Europe·1

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Category: Market Segments
Acronym: LDT
Sources: 3
Updated: 5/5/2026

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IVD designed, manufactured, and used within a single CLIA laboratory.

·Many oncology, infectious disease, and rare-disease tests reached patients as LDTs.
·The FDA LDT rule, ongoing litigation, and CMS PAMA repricing are key uncertainties.
·FDA historically exercised enforcement discretion; a 2024 final rule began phasing in active oversight.

Remember this

Watch out: A key misconception is that CLIA certification alone is sufficient for regulatory compliance of an LDT.

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