The US Food and Drug Administration (FDA) is proposing to step up its oversight of a growing category of medical tests called Laboratory-Developed Tests (LDTs). The FDA approves and clears many types of lab tests for blood, saliva or tissue if they are used by many different hospitals or labs. However, for almost 50 years, the Agency has given individual labs leeway to develop and use their own tests in-house, as long as the labs met certain standards. Typically, labs using LDTs were based in hospitals and academic medical centers, and served patients of those institutions. Over time, larger companies started to make and market specialty tests, including direct-to-consumer genetic tests, under the more lenient lab-developed testing rules.
Today, millions of people may use these kinds of lab-developed tests, without necessarily knowing that the tests generally do not have to meet the same standards as other types of tests. The LDTs have become increasingly sophisticated, relying on automation and software to produce results. Many are indistinguishable from the types of tests the FDA vets before they go on the market.
At the end of September 2023, the Agency said that because of the growing use of these lab-developed tests and their importance in medical decision-making — some 70% of medical decisions depend on lab tests, according to data from the US Centers for Disease Control and Prevention (CDC) — it proposed a rule aimed at increasing its oversight. The proposed rule would treat laboratory-developed tests as medical devices and end the Agency’s hands-off stance on them. “These widely used tests are not generally coming to the FDA for review or otherwise complying with FDA requirements,” said FDA Commissioner Dr. Robert Califf, in a news briefing. “This leaves Americans vulnerable to making important health care choices based on potentially faulty or inaccurate test results. This should not continue,” Califf said.
Because labs that develop their own tests do not have to register them with the FDA, no one knows exactly how many of them are on the market or how well they work. The FDA’s proposed rule would change that. It would require manufacturers to register their tests with FDA, and the Agency would review lab tests based on their risk to patients, said Dr. Jeffrey Shuren, Director of the FDA’s Center for Devices and Radiological Health (CDRH).
The proposed rule says that even though no one systemically collects instances of patient harm due to lab-developed tests, the Agency has enough evidence from anecdotal reports and independent research to increase regulation of these tests.
The proposed rule cites one (1) study in which the same samples were sent to 19 laboratories for testing using their own manufactured tests, and only seven (7) of those labs correctly reported all results. In another study, researchers sent identical samples to two different laboratories to detect tumor mutations and found over 70% discordance in the results from their tests, the proposed rule says. The FDA has also interacted with test developers who are seeking authorization.
“FDA has observed that many laboratories fail to perform appropriate or adequate validation studies, have data demonstrating their test does not work as intended but offer the test anyway, or use instruments and other components that are not adequately controlled for clinical use,” the proposed rule says. For example, out of the first 125 Emergency Use Authorization (EUAs) requests for Covid-19 diagnostics, 82 showed test design or validation problems, according to the proposed rule. The Agency says that its action today does not mean all lab-developed tests are bad; however, that a better approach to oversight is needed.
The proposal drew fire from Sen. Bill Cassidy, a Louisiana Republican who is ranking member of the Senate Health, Education, Labor and Pensions Committee. “The FDA does not have the authority to unilaterally expand its regulatory jurisdiction. We saw during the pandemic how too much government interference and red tape could do more to delay lifesaving care,” Cassidy, a physician, said in a statement. “While past legislative efforts may have missed the mark, it is time for Congress to assert itself and clarify FDA’s authority in the regulation of diagnostic tests.”
The Agency’s enforcement discretion for Laboratory-Developed Tests (LDTs) would be phased out over five (5) years to give manufacturers time to adjust. In the first year, labs would have to report adverse events and malfunctions linked to their tests, and these tests would be subject to “the equivalent of recall” and would move on from there to premarket review later down the line, Shuren said. Shuren did not give a date for when the Agency expected the proposed rule to be finalized, saying that would be up to the administration.
REFERENCE: CNN Health; 29 SEP 2023; Brenda Goodman