Laboratory Developed Tests: Current FDA Regulatory Status

A laboratory developed test (LDT) is an in vitro diagnostic test that is designed, manufactured, and used within a single laboratory, rather than a test kit manufactured for sale to and use by multiple laboratories. LDTs have historically been regulated primarily under the Clinical Laboratory Improvement Amendments (CLIA), enforced by the Centers for Medicare & Medicaid Services (CMS), rather than as FDA-regulated medical devices — a distinction FDA has, at various points over the past two decades, proposed changing.

The current position, as of FDA’s most recent update (September 19, 2025)

Per FDA’s own published statement on its Laboratory Developed Tests page (content dated current as of September 19, 2025):

• May 6, 2024 — FDA issued a final rule amending the definition of “in vitro diagnostic products” in 21 CFR 809.3(a) to add the words “including when the manufacturer of these products is a laboratory.” This change, phased in over several years, would have brought LDTs within FDA’s general medical device framework (registration, listing, adverse event reporting, premarket review pathways, and quality system requirements) rather than leaving them under CLIA-only oversight.
• March 31, 2025 — A federal district court vacated that final rule.
• September 19, 2025 — FDA issued a final rule (published in the Federal Register, RIN 0910-AJ05) reverting the text of 21 CFR 809.3(a) to how it read before the May 2024 final rule took effect.

The practical effect: as of FDA’s September 2025 reversion, the regulatory text does not currently include laboratories that manufacture their own tests within the definition of an in vitro diagnostic product “manufacturer” for general device-regulation purposes. LDTs are, for now, back to being regulated primarily as clinical laboratory services under CLIA (and applicable state law, such as New York State’s separate LDT approval program) rather than as FDA-regulated devices under the vacated 2024 framework.

Why this matters for laboratories now

Because the 2024 rule was vacated rather than simply repealed by FDA on policy grounds, the underlying legal and policy questions have not been permanently settled — a court ruling that a specific final rule was procedurally or substantively invalid does not by itself prevent an agency from pursuing a different rulemaking in the future, and FDA’s proposed and finalized rules on LDTs going back to 2023 show sustained agency interest in this area. Laboratories currently offering LDTs should treat the present CLIA-primary framework as the operative one for compliance purposes today, while recognizing that:

• CLIA certification and applicable CLIA quality requirements (personnel, quality control, proficiency testing) remain the primary federal compliance framework for most LDTs
• State-level requirements can be more stringent than federal CLIA requirements and are unaffected by this FDA rulemaking history — New York State’s Clinical Laboratory Evaluation Program (CLEP) approval requirement for LDTs offered to New York patients is a commonly cited example of a state regime that operates independently of FDA’s device framework
• FDA retains its traditional authority to regulate IVD test kits sold to multiple laboratories as devices; that authority is not affected by the LDT-specific rulemaking history above
• Laboratories should not assume the current position is permanent — given the history of proposed rulemaking (2023), a final rule (2024), vacatur (2025), and reversion (2025) in close succession, checking FDA’s LDT page directly before a compliance decision is the safer practice

Timeline of LDT rulemaking

• 2010 — FDA holds a public workshop on LDT oversight, an early step in a long-running policy discussion.
• 2014 — FDA issues (but does not finalize) draft guidance proposing a risk-based LDT oversight framework.
• September 29, 2023 — FDA proposes a rule to explicitly include LDTs within the IVD “manufacturer” definition.
• May 6, 2024 — FDA finalizes that rule, with a phased compliance timeline over several years.
• March 31, 2025 — A federal district court vacates the final rule.
• September 19, 2025 — FDA issues a final rule reverting 21 CFR 809.3(a) to its pre-May-2024 text.

Frequently asked questions

Are LDTs FDA-approved?

No, and this has not changed with the rulemaking history above. LDTs are generally not FDA-cleared or -approved products; they have historically been offered under a laboratory’s CLIA certification rather than through an FDA premarket device pathway. The vacated 2024 rule would have moved toward requiring FDA device-level oversight in most cases; that rule is not currently in effect.

Does CLIA certification alone make an LDT compliant?

CLIA certification with its associated personnel, quality control, and proficiency testing requirements is the primary federal compliance framework for LDTs under the current (post-reversion) regulatory text, but laboratories should also confirm any state-specific requirements (such as New York’s CLEP program) that apply independently of the federal CLIA/FDA framework.

Could FDA revisit device-level regulation of LDTs again?

Nothing in the September 2025 reversion forecloses future rulemaking. Given FDA’s history of proposing (2023), finalizing (2024), and then reverting (2025) LDT-specific device regulation within about two years, laboratories should monitor FDA’s LDT page directly rather than treat the current position as permanent.

Sourced from FDA’s Laboratory Developed Tests page, content current as of September 19, 2025 (fda.gov/medical-devices/in-vitro-diagnostics/laboratory-developed-tests). This guide reflects that stated position and does not independently confirm any status change after that date.

See also: CLIA High Complexity Testing Requirements: Personnel, QC, and Validation and ISO 15189 Accreditation: Requirements, Audits, and How It Differs from CLIA and ISO 17025.