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Disclaimer

The information on these pages is specifically intended for use by staff at state and local public health laboratories in the United States. The content reflects APHL's interpretation of Laboratory Developed Test (LDT) policies and regulations, and the information may not be directly applicable to other laboratory sectors

The issue of regulating LDTs is a rapidly evolving area and there are currently many legal and political issues and considerations that may influence outcomes. Additionally, the US Food and Drug Administration (FDA) is still responding to comments that the Agency has received, so the regulatory guidance and requirements are likely to change over time.

While we will endeavor to provide you with the most accurate information as we understand it at the time and will work to keep this website current, APHL cannot guarantee that we will be able to do so, and we encourage you to independently verify information contained on this page.


APHL and its members are committed to ensuring that the testing performed in public health laboratories (PHLs) is of the highest quality and meets all federal regulatory requirements. Historically, many tests have been developed and validated under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) as laboratory developed tests (LDTs) by state and local PHLs to meet the public health needs of the communities they serve. These LDTs are employed in the areas of infectious diseases, newborn screening and the detection of environmental chemicals in human specimens.

On May 6, 2024, the FDA released a Final Rule indicating that the Agency will, in a phased manner over the next four years, discontinue enforcement discretion of LDTs and will treat them as in vitro diagnostic products (IVDs) which are devices under the Federal Food, Drug, and Cosmetic Act (FD&C Act). Laboratories, including PHLs, will now be considered manufacturers of IVDs and will be required to have their LDTs reviewed and approved by the FDA. The roll-out of the Final Rule will create a very different regulatory environment for tests developed by PHLs.

APHL has recorded this webinar​ (slides​) to provide an overview of how PHLs will respond to the requirements of the Final Rule for the most commonly used LDTs.​

Inside this ​​​​Resource

In the dropdown fields below you will find the following information: ​​

  • APHL Support for Members: Outline of the actions APHL​ has taken or plans to take to support our member laboratories through this regulatory transition.

  • ​​General LDT Information and History: A brief history of LDT regulation and summary of the FDA Final Rule.

  • Key Facts: Contains significant points extracted from the Final Rule that will likely impact the operation of PHLs (Italicized text within "quotation marks," taken directly from the FDA website), with APHL's interpretation in plain language below.

  • Enforcement Discretion Phaseout Policy: Outlines what the FDA will require of PHLs over each of the four years during which enforcement discretion will be phased out.

  • Frequently Asked Questions: A series of questions and answers that have often been asked.

  • Test Implementation Resources: A list of existing materials (guidance, toolkits, examples, etc.) that may be helpful for implementing new tests. APHL is developing a set of templates that can be completed by each laboratory to fulfil the FDA requirements at each stage; they will be uploaded to this section when published.

  • APHL Comments and Materials: A list of comments APHL has submitted to FDA or Congress about LDTs, and related presentations, position statements and guidance resources. 

  • FDA Resources: Additional materials about LDTs from FDA, including an FAQ, regulation summaries and relevant regulations, final rules and notices.

  • FDA Webinars: Recordings of FDA's informational sessions on LDTs.

  • Other Resources and Webinars: Additional material and informational sessions on LDTs from other members of the laboratory community.

  • Definitions: Key terms for reference.