Summary: Feedback from a new ADLM survey reveals that the FDA’s final rule on laboratory-developed tests (LDTs) will likely reduce patient access to crucial tests, despite exemptions designed to mitigate these impacts.


  1. Resource Constraints: Despite certain exemptions in the FDA’s final rule, many clinical laboratories, especially those in hospitals, report insufficient staff and resources to meet the new regulatory requirements, predicting a reduction in the availability of essential tests.
  2. Impact on Critical Testing: The rule may lead to the discontinuation of vital toxicology tests, such as those for detecting low concentrations of substances like fentanyl and methamphetamine, which are crucial for addressing public health issues like substance abuse and overdose deaths.
  3. Regulatory Challenges: The survey highlights concerns within the clinical laboratory community that the FDA’s regulatory framework, although well-intentioned, is not suited for the unique nature of LDTs, which are developed and used within a single lab and are not mass-produced like other medical devices.

The Association for Diagnostics & Laboratory Medicine (ADLM, formerly AACC) released the results of a survey that ADLM conducted to determine how the Food and Drug Administration’s (FDA’s) final laboratory-developed tests rule will impact patient access to essential tests. The survey found that, in spite of certain tests being exempt from the rule, it will still force many laboratories, particularly those in hospitals, to discontinue critical tests, including those needed to identify prescription and illegal drug use.

FDA’s Final Rule on LDTs

On April 29, the FDA published a final rule on laboratory-developed test regulation that will place these tests under FDA oversight, in addition to the Centers for Medicare & Medicaid Services (CMS) oversight that they are already under. ADLM has long contended that labs do not have the resources to meet the FDA’s regulatory requirements on top of CMS’, and that this duplicative regulation will push many labs to stop performing these essential tests. The FDA, on the other hand, has emphasized that the final rule exempts certain categories of laboratory-developed tests from the agency’s full review process, though exempt tests will still be subject to other regulatory requirements. These exempt tests include so-called grandfathered tests that were offered prior to the publication of the rule, as well as tests that fill an unmet need that no FDA authorized test addresses. After the rule is phased in, which will happen over the course of four years, the FDA claims that these exemptions will ensure that patients have the same access to testing that they do in the present.

Further reading: ACLA Files Suit over FDA’s LDT Final Rule

The ADLM LDT Survey

ADLM conducted a survey to learn directly from labs whether the FDA rule’s exemptions will help or hurt their testing capabilities. The survey went out to clinical laboratories across the U.S. and received responses from 128 of them. In spite of the rule’s exemptions, the majority of respondents said that they do not have the staff or resources to fulfill the FDA requirements that exempt laboratory-developed tests will still have to meet. And more than half of the labs that won’t be able to comply with these requirements anticipate discontinuing some of their exempt tests.

The tests that labs could end up discontinuing include essential toxicology tests for fentanyl, methamphetamine, barbiturates, and cocaine. These laboratory-developed drug tests are crucial because, unlike their FDA approved counterparts, they are able to detect these drugs at their lowest concentrations. Labs can also modify their laboratory-developed tests quickly, enabling them to detect designer drugs as soon as they emerge. This makes these tests indispensable in the fight to curb substance abuse and overdose deaths, which surpassed 100,000 for the third straight year in 2023.

“We appreciate that the FDA has tried to include provisions in its final rule with the aim of preserving patient access to laboratory developed tests,” says ADLM President Octavia Peck Palmer, PhD. “But the fact still remains that clinical labs are not medical device manufacturers, nor are laboratory developed tests the mass manufactured devices that the FDA currently regulates. This means that the FDA’s regulatory framework is simply not appropriate for laboratory developed tests, and the results of ADLM’s survey demonstrate that placing these tests under FDA oversight will only hinder patient care and critical public health initiatives.”

Further reading: Is the LDT Final Rule a Sword of Damocles?

About LDTs

A laboratory-developed test is a new or significantly modified test that is developed, validated, and used within a single clinical laboratory in response to a specific patient care need. Most laboratory-developed tests are created because there is not already a Food and Drug Administration-approved test available, and they are often used to diagnose rare conditions, such as inherited genetic disorders. These tests are typically not advertised or sold as kits to other testing facilities.

The only labs that are allowed to perform laboratory-developed tests are those that are considered high-complexity labs under the Clinical Laboratory Improvement Amendments, which are administered by the Centers for Medicare & Medicaid Services (CMS). These high-complexity labs are subject to rigorous oversight under CMS, and they are routinely inspected to ensure that they provide highly accurate testing.

Photo courtesy of the new ADLM survey