The first company to get Food and Drug Administration approval to sell its over-the-counter COVID tests is recalling nearly 200,000 of the kits sold by retailers including Amazon, CVS, Target and Walmart after a larger-than-expected rate of false positives.

The recall involves 43 lots distributed to retailers and the Department of Defense between April and August, test kit-maker Ellume said in a notice posted on its website. The specific lots reported higher positivity rates than seen in clinical trials, prompting the Brisbane, Australia-based company to look into the issue, which it said it was working to fix. 

“Following a thorough investigation, we isolated the cause and confirmed that this incidence of false positives is limited to specific lots,” Dr. Sean Parson, Ellume’s CEO and founder said in a statement. “We recognize that this incident may have shaken the confidence of some of those who trusted Ellume to help them manage their health and take back a bit of control of their lives during this pandemic,” added Parson, who apologized for “any stress or difficulties” to those who falsely tested positive.

There were about 427,000 tests in the lots being recalled, with about 195,000 unused and subject to the recall, the company relayed to CBS MoneyWatch in an emailed statement. Approximately 160,000 of the tests produced negative results considered reliable, while about 42,000 produced positive results, “which include both true positives and false positives,” according to the company.

Ellume is notifying those affected by the recall, and those who try to use the affected tests will be told in the company’s app that the test has been recalled and disabled. 

People who purchased an Ellume kit can check whether it’s part of the recall here, as well as request a replacement test. The company can also be reached Monday through Friday, 9 a.m. to 5 p.m. EST, at 1(888) 807-1501. 

The FDA flagged the issue on Tuesday, saying it was working with Ellume to make sure the manufacturing issue is resolved. 

Ellume’s rapid antigen test in December became the first at-home test to receive emergency use authorization from the FDA. The agency on Monday authorized a new at-home antigen test, ACON Laboratories’ Flowflex. 

The Biden administration last month said it was partnering with retailers including Amazon, Kroger and Walmart to make the at-home rapid tests less costly and easier to get. The White House in recent days said it would invest another $1 billion in putting more of the tests on the market.