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    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.
    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.

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    Primary references

    3 sources
    Link health: 3 verified· last checked 2026-06-20
    FDA·1AdvaMed·1MedTech Europe·1
    1. 1
      FDA LDT final rule
      Verified
      FDAfda.gov
    2. 2
      AdvaMed - Industry Reports
      Verified
      AdvaMedadvamed.org
    3. 3
      MedTech Europe - Facts & Figures
      Verified
      MedTech Europemedtecheurope.org

    Inline markers like [1] jump to the matching reference above.