Ellume Ltd. is recalling 2.2 million at-home COVID-19 tests because they risk returning false positives, the U.S. Food and Drug Administration said.

The regulator classified the action on Wednesday as a class I recall, the most serious kind, saying it has received 35 reports of false positives from the test made by the Australian company. Incorrect results could lead a person to wrongly receive COVID-19 treatments or isolate when they don’t need to, the FDA said.

“The Ellume team offers its sincere apologies for the stress or difficulties people may have experienced due to a false positive result,” a company spokesperson said in an email. “We have and will continue to work diligently to ensure test accuracy, in all cases.”

The spokesperson said that Ellume has identified the cause of the problem, put new control measures in place and is now making and sending new tests to the U.S.

(A Hawaii Department of Health spokeswoman said, “Hawaii has not received any Ellume test kits through the federal government and the state has not participated in any programs involving Ellume test kits.”)

Ellume had shipped 3.5 million tests to the U.S. as of October. The recalled tests were distributed between mid-April and late August, the FDA said. A previous recall in October affected about 195,000 unused Ellume tests, the startup said at the time.

One of the Biden administration’s earliest moves on COVID-19 testing was a $232 million investment into expanding Ellume’s manufacturing. The company’s product was the first of its kind to be cleared for use without a prescription by the FDA, in late 2020.

Ellume’s self-administered, single-use test is akin to an over-the-counter pregnancy test. Sold for roughly $30, it uses a swab to detect proteins known as antigens on the coronavirus’s surface and returns results in 15 minutes.

Earlier Wednesday, the Biden administration announced a $650 million investment in rapid diagnostic tests for confirming at-home screening results. Earlier this fall, the U.S. said it plans to spend $3 billion to expand the supply of at-home tests.

Star-Advertiser staff contributed to this report.