Lab-developed tests (LDTs) are diagnostic tools widely used across health care to test blood, tissue or other samples for infectious diseases, genetic markers, or other biomarkers of many conditions.
Unlike tests manufactured and marketed commercially, LDTs are designed and used within a single lab that meets certain stringent standards.
According to researchers, they’re invaluable tools for patient care because they “are often developed out of necessity because no test is available for purchase, or the currently available assays do not meet the needs of a specific patient population.”
Since lab-developed tests are not widely marketed, they have been in a regulatory “gray zone” with minimal FDA oversight for nearly 50 years. Last year, the FDA issued a final rule aimed at stronger regulation of these tests. However, on March 31, a Texas federal court ruled that the FDA had overstepped its authority and vacated the FDA’s final rule in its entirety.
Journalists investigating lab-developed tests and the implications of the court’s decision can find a wealth of stories by diving into the various uses of LDTs and how they have helped or harmed patients.
What’s new
In an April 2024 press release, the FDA highlighted the need for tighter regulation of lab-developed tests, since the tests could potentially harm patients if they are unsafe, inaccurate or of poor quality.
“Without greater oversight of the safety and effectiveness of LDTs, patients may be more likely to initiate unnecessary treatment, or delay or forego proper treatment,” the press release stated. “This could result in harm, including worsening illness or death, as well as unnecessarily increase health care costs.”
The March ruling “will avoid adding billions of dollars to health care costs and protect access to high-quality care for hundreds of millions of Americans,” Jane S. Gibson, president of the Association for Molecular Pathology (AMP), who together with the American Clinical Laboratory Association (ACLA) had brought the lawsuit against the FDA, said in a statement.
But other groups have spoken in favor of greater regulation of these tests, highlighting the need for accurate results regardless of where a test is performed. In 2015, the FDA highlighted 20 case studies where lab-developed tests had caused harm: in some instances, people were diagnosed with conditions they did not have, and in others, the tests failed to spot life-threatening diseases. In an amicus brief filed last year, a group of organizations wrote: “Cancer patients and their physicians should be able to trust the information produced by a diagnostic test regardless of where that test is conducted.”
Broad umbrella
An LDT might be a reagent, instrument, algorithm, blood or saliva test, or any number of a wide variety of diagnostic tools that clinicians can use. The earliest instances of lab-developed tests date back to the 1930s, and nearly 80,000 are currently in use. The FDA estimated that its final rule would also cover several thousand new tests annually.
Because LDTs can be developed and deployed more quickly than commercial, FDA-approved tests, they play a critical role in health care. For example, lab-developed tests were among the earliest tests available during the COVID-19 pandemic and played a crucial role in detecting infections during the 2022 monkeypox outbreak. Other available LDTs help to determine the right cancer treatments, seek out genetic risk markers for disease or adverse drug reactions, identify rare diseases, infections and more.
Lab-developed tests often fill gaps in care for children, for whom certain tests may not be approved, and for underserved populations who lack access to commercial tests, or immunocompromised patients who may not be able to undergo standard testing procedures. The long history of LDTs and their varied uses provide rich material for stories.
Story ideas to consider:
- Explore equity: In Arizona and New Mexico, endemic infections such as hantavirus and Valley fever, a fungal infection, place an undue burden on Indigenous communities. No FDA-approved tests exist for these infections, and LDTs may play a crucial role in reducing the burden of these infections amongst Indigenous people.
- Follow emerging infections: As measles, pertussis, and other infectious diseases rise across the country, report on novel lab-developed tests that may help communities track these infections.
- Investigate algorithms: Newer lab-developed tests can rely on proprietary algorithms developed within a single laboratory. Investigate how these LDTs were vetted and whether the populations they serve were sufficiently represented when developing algorithms.
- Track regulations: Are efforts to make lab-developed tests more harmonious across labs still underway? Speak with regulators, policymakers, and patient advocates who supported more oversight to learn what comes next.
