Jan 23, 2017


  • The US FDA has indefinitely delayed final guidance for oversight of laboratory developed tests (LDTs) following industry feedback on proposed regulation of these devices.
  • A suggested LDT framework from the FDA would “grandfather” in many types of these products without imposing new premarket review or quality management requirements.
  • The FDA has suggested a four-year phased implementation of market authorization requirements for LDTs, but this is only a suggested approach at this time.

US medical device regulators at the Food and Drug Administration have put on hold plans to publish final guidance regarding laboratory developed tests (LDTs) in order to develop a more appropriate oversight approach, according to the agency.

In a recent discussion paper, the FDA notes that considerable feedback from industry and other stakeholders on draft guidance for LDT oversight in 2014 led the agency to back off planned final guidance in early 2017. Comments on the draft guidance often questioned or criticized the agency’s proposed oversight framework for LDTs; the discussion paper includes a proposed framework based on some of this feedback on the draft guidance.

The LDT issue: More oversight to prevent faulty tests

US regulators proposed more stringent requirements for LDTs in 2014  in response to proliferation of such products for various consumer and clinical healthcare-related applications—along with potential risks to patients that faulty or false tests may bring. Plus, no uniform oversight mechanism currently exists to cover all LDT products.

The FDA’s discussion paper warns that “currently, patients and providers cannot uniformly rely on all tests offered for clinical use as some are not subject to active premarket oversight to ensure they provide accurate measurments as valid claims.”

More active and consistent oversight is necessary, the FDA has argued, to prevent faulty LDTs from being sold in the US.

Towards “focused oversight”

Under a prospective oversight approach the FDA proposed in its discussion paper, LDTs previously marketed in the US would be grandfathered into a new regulatory framework; these LDTs would not have to comply with FDA premarket review, quality system and registration requirements unless the agency determines such steps necessary to protect the public health.

Additional types of new and significantly modified LDTs that would not normally fall under FDA oversight would include LDTs for rare diseases; LDTs intended only for public health surveillance or forensic use; low-risk LDTs; and LDTs used in some Clinical Laboratory Improvement Amendments (CLIA)-certified high-complexity labs.

However, the FDA would keep its oversight options at the ready for LDTs in the following instances:

  • An LDT is not clinically or analytically valid, or the manufacturer does not have adequate data to support such validity
  • An LDT manufacturer engages in deceptive promotion
  • An LDT will probably cause death or serious injury

For oversight of new and significantly modified LDTs that do not fall into one of the categories mentioned above, the FDA suggests a four-year, phased approach toward regulation. In its draft guidance, the agency had proposed a nine-year phase-in for premarket review requirements.

Year One of the phase in would entail serious adverse event and malfunction reporting for all LDTs except traditional LDTs intended for public health surveillance, some LDTs used for transplantation procedures and LDTs for forensic uses.

Year Two would see premarket reviews for new and modified LDTs that share the same intended uses as high-risk in vitro diagnostic (IVD) devices that have undergone Premarket Approval (PMA) by the FDA.

Year Three would introduce premarket reviews for LDTs with the same intended uses as Class II devices subject to 510(k) clearance.

Year Four would entail premarket reviews for any LDTs that do not fall under the categories listed in the previous three year periods.

However, it must be emphasized that the oversight framework outlined in the discussion paper is only a suggestion—until the FDA issues additional guidance on LDT regulations, no definitive oversight pathway for these products can be mapped out.

Emergo analysis: A prudent response to a tricky issue

Significant differences between LDTs and other types of medical devices and IVDs, as well as the role they play in various healthcare settings, make it difficult to simply extend existing regulations for other devices to LDTs without careful consideration.

According to Oliver Eikenberg, a Senior QA/RA Consultant at Emergo in Germany with extensive experience in the LDT arena, the FDA’s latest discussion paper on LDT oversight reflects a delicate balance the regulator is trying to achieve here.

“The CLIA and FDA worlds are completely different, and as such, in designing an appropriate oversight system for these products the FDA has to strike a critical balance,” Eikenberg says. “The FDA has to have control over these devices and protect public health, but not kill working laboratory procedures for patients. The suggestion of a step-by-step, risk-based approach is in my view an attempt in this direction.”



  • Stewart Eisenhart