A move by the U.S. Food and Drug Administration (FDA) to regulate diagnostic tests developed in thousands of laboratories is picking up steam—and drawing fire. The agency recently notified Congress that it plans to regulate some of these so-called laboratory developed tests (LDTs)—which, unlike tests marketed by diagnostic manufacturers, don’t currently require FDA approval. FDA has not yet released a draft guidance on the matter, but at a hearing yesterday, members of the U.S. House of Representatives Energy & Commerce Committee’s health subcommittee raised questions about the agency’s authority to regulate these tests, its motivation for doing so, and the potential impact of such regulations on the diagnostic industry.
Doctors use diagnostic tests to determine which patients are at risk for developing a disease and which would benefit from a treatment. And while companies offer FDA-approved kits for many of these uses, clinical labs often design and offer their own. According to the American Clinical Laboratory Association (ACLA), more than 11,000 laboratories are authorized to develop and perform LDTs, and the majority of them do.
FDA has had the authority to regulate LDTs—and all in vitro diagnostics—since 1976, explained Jeffrey Shuren, director of FDA’s Center for Devices and Radiological Health, at the hearing. But the agency has so far exercised “enforcement discretion” and has not required that labs manufacturing these tests seek its approval. Labs have instead been regulated by the Centers for Medicare & Medicaid Services through the 1988 Clinical Laboratory Improvement Amendments (CLIA).
But LDTs aren’t what they used to be, Shuren told the subcommittee. They’re manufactured in large quantities and are increasingly removed from the health care centers and doctors who order them. They are also increasingly complex, relying on sophisticated software to interpret results. Although CLIA ensures that labs perform a test properly, it doesn’t address the clinical validity of the test itself—how accurately it measures a patient’s condition. “We have a responsibility to provide patients with greater certainty,” Shuren said.
That’s why FDA has for years been angling to regulate LDTs and is now developing a draft guidance for labs to seek its approval. The new requirements wouldn’t apply to all tests. Those that FDA considers “low-risk,” those that diagnose rare diseases, and those that have no FDA-approved equivalent would continue to enjoy enforcement discretion. But for the rest, labs would have to submit data proving their validity. But it’s not yet clear how many labs would be subject to the new requirements.
Some lawmakers and stakeholders balk at the thought of FDA’s increased involvement. Alan Mertz, president of ACLA and a witness at the hearing, argued that the proposed regulations would discourage labs from developing innovative new tests and prevent them from adjusting the tests quickly for new uses. Mertz, along with several representatives, also challenged FDA’s authority to regulate LDTs, arguing that they are not “devices” but rather services provided to a patient, and are already regulated effectively under CLIA.
But others welcome FDA’s move to raise the regulatory bar. Christopher Newton-Cheh, a cardiologist at Massachusetts General Hospital in Boston who testified on behalf of the American Heart Association, called the current system “completely opaque.” Doctors often aren’t aware if the test they order is FDA-approved, and inaccurate results increase the risk that patients will undergo unnecessary treatment or be excluded from a treatment based on bad information. “This is the right thing to do for patients,” he said.
FDA may release its draft guidance on or after 29 September. Once the agency finalizes the guidance, it intends to phase in the new review process over 9 years.