Australian manufacturer Ellume is recalling about 2 million at-home COVID-19 test kits over concerns about "higher than acceptable" false positives.
The company first initiated the recall in October for a few thousand kits, but this week it was expanded, the Food and Drug Administration (FDA) said Wednesday.
The agency identified the recall as Class I, or the most serious type, and said use of the tests "may cause serious adverse health consequences or death."
The reliability of negative test results has not been impacted, the FDA and the company said.
The defective tests were manufactured by Ellume between Feb. 24 and Aug. 11 of this year. There have been 35 reports of false positive results sent to the FDA and no deaths reported.
The company is recommending anyone who received a positive result from one of the affected lots in the past two weeks should confirm the result with a molecular diagnostic test.
The test uses swab samples taken from further up inside the nose, but not as deep inside the nose to reach the back of the throat where a health professional collects a sample.
The test uses an analyzer that connects with a smartphone app to show users how to perform the test and understand the test results.
Affected tests purchased by consumers but not yet used will be disabled via a software update, FDA said. Ellume will also inform customers who used an affected test and received a positive result.
In February, the Biden administration inked a nearly $232 million deal with Ellume for the mass production of rapid COVID-19 tests to boost capacity on the U.S. market. As part of the deal, the administration helped fund the opening of the company's first plant in the U.S.
In a statement posted to the company website, Ellume CEO Sean Parsons apologized to those who were affected by false positive results.
"We understand that trust is central to fulfilling our purpose as a company, and we recognize that this incident may have shaken the confidence of some of those who trusted Ellume to help them manage their health and to take back a bit of control of their lives during this pandemic," Parsons said. "To those individuals, I offer my sincere apologies — and the apologies of our entire company — for any stress or difficulties they may have experienced because of a false positive result."
At-home tests, which can deliver results in as little as 15 minutes, are seen as a key tool to use for schools, workplaces and large events like conferences, concerts and weddings. They're regularly used overseas, but the U.S. has been far more cautious in allowing rapid tests to come to the market.
Demand for at-home tests has been extremely high, and supplies have been limited. The FDA last month streamlined the process for at-home tests to reach the market, and the Biden administration announced an additional $1 billion to purchase millions of tests in order to boost capacity.