FDA LDT Rule: 3 key changes for Laboratory Developed Tests (LDTs) in the US

July 1, 2024
3 min read

Earlier this year the FDA has introduced significant regulatory changes for Laboratory Developed Tests (LDTs) to enhance their oversight and ensure higher standards of safety and effectiveness. These changes align LDTs with the regulatory requirements for other in vitro diagnostic (IVD) tests, marking a shift towards more rigorous regulation and quality control. Below are the three most important regulatory changes and their implications for LDTs.

1. End of Enforcement Discretion

Historically, the FDA had exercised broad enforcement discretion over LDTs, meaning that many LDTs were not rigorously regulated. The new regulatory framework ends this discretion, bringing LDTs under the same stringent regulatory requirements as other in vitro diagnostic (IVD) tests. This change ensures that all diagnostic tests undergo appropriate regulatory scrutiny to guarantee their safety and effectiveness. The shift means that LDTs will now be subject to more rigorous FDA oversight, including premarket reviews, adherence to quality standards, and post-market surveillance.

2. Premarket Review Requirements

Under the new regulations, LDTs will need to undergo premarket review by the FDA. Depending on the risk classification of the test, this could involve either a Premarket Approval (PMA) application, which is necessary for high-risk devices, or a 510(k) premarket notification, which applies to moderate-risk devices. The premarket review process involves evaluating the test's analytical and clinical validity to ensure that it accurately and reliably measures what it claims to measure and that it is safe and effective for its intended use.

3. Quality System Regulations

LDT manufacturers must now comply with the FDA's Quality System Regulations (QSR). These regulations set comprehensive requirements for the methods used in, and the facilities and controls used for, the design, manufacture, packaging, labeling, storage, installation, and servicing of all finished devices intended for human use. Compliance with QSR ensures that LDTs are consistently produced and controlled according to quality standards, reducing the risk of defects and ensuring high reliability and performance of the tests. QSR will involve amongst other topics:

  • Design Controls: Establish and maintain procedures to control the design of the device to ensure specified design requirements are met. For instance, during the development of a new genetic test, the lab must document the design process and validate the test’s performance through rigorous testing.
  • Production and Process Controls: Develop processes to ensure products are consistently manufactured according to established specifications. For example, a lab producing a blood glucose test must implement standardized procedures for the preparation of reagents and the assembly of test kits.
  • Corrective and Preventive Actions (CAPA): Establish a system for identifying and addressing non-conformities and potential issues in the manufacturing process. For instance, if a lab identifies an error in the test results, it must investigate the root cause and implement measures to prevent recurrence.
  • Document Controls: Implement procedures for managing documents, ensuring that all records are accurate, accessible, and reviewed regularly. For example, a lab must maintain detailed records of test development, manufacturing processes, and quality control measures, ensuring these documents are up-to-date and properly archived.

These regulatory changes aim to enhance the overall quality and safety of LDTs, aligning them with the standards expected of all diagnostic devices to ensure better patient outcomes and public health protection.

Get in touch: info@ambiom.com



No comments.


ambiom s.r.o.
Karpatské námestie 7770/10A
831 06 Bratislava
IČO: 54219035


+421 948 652 276



Back to top Arrow