Ellume, an Australian company that makes a widely used coronavirus home test, has recalled nearly 200,000 test kits amid concerns about an unexpectedly high rate of false positives. This corresponds to about 5.6 percent of the roughly 3.5 million test kits that Ellume has delivered to the USA.
The company, which discovered the problem in mid-September, attributed the problem to variations in the quality of one of the raw materials used in the test kit, said Dr. Sean Parsons, CEO of Ellume, in a telephone interview. He declined to specify the material in question because he did not want to publicly disclose the exact functionality of the test kits.
Approximately 427,000 test kits, including some made available to the Department of Defense, were affected by the problem, said Dr. Parsons. About half have already been used, he said, with about 42,000 positive results. Up to a quarter of these positive results could have been inaccurate, said Dr. Parsons, although he did stress that it would be difficult to pinpoint exactly how many.
“I am very sorry that this happened,” said Dr. Parsons. “We care about accuracy, and these false positives are disappointing.”
The problem did not affect all Ellume test kits or the reliability of negative results, the company said.
The Ellume test is a rapid antigen test that can be used to detect parts of the virus in the nose. Users wipe their nostrils, insert the swab into a dropper of liquid, and then put the liquid into an analyzer connected via Bluetooth. The results are transferred to a smartphone app in 15 minutes. Last December, it became the first over-the-counter, fully-at-home test to receive emergency clearance from the US Food and Drug Administration.
The company has asked retailers to take the tests off their shelves and is in the process of notifying consumers, said Dr. Parsons.
Consumers who have any of the affected tests can request a replacement online. People who try to use one of the affected test kits will be notified in the app that the test has been recalled. “It really won’t be possible to use any of these tests now,” said Dr. Parsons.
He added that the company put “additional controls” in place to prevent the same problem from occurring again in the future.
“We are doing everything we can to bring a well-known, good product into the hands of consumers in the USA,” said Dr. Parsons.
The recall comes as the demand for tests has increased and consumers have complained that home test kits are difficult to find.
On Monday, the FDA approved a new home antigen test, Flowflex from ACON Laboratories. The approval “is expected to double the rapid test capacity at home in the US in the next few weeks,” said Dr. Jeffrey E. Shuren, who directs the FDA’s Center for Devices and Radiological Health, in a statement. “By the end of the year, the manufacturer wants to produce more than 100 million tests per month, and by February 2022 it should be 200 million per month.”