The Australian company Ellume has expanded a recall of its at-home coronavirus test because of concerns about a “higher-than-acceptable” rate of false positives, the U.S. Food and Drug Administration said on Tuesday.
The recall now includes roughly two million of the 3.5 million test kits that Ellume had shipped to the United States by last month, a substantial increase from the company’s earlier estimate that about 427,000 of those kits were potentially faulty.
It is not clear how many false positives the affected tests have yielded. The issue, which the company had previously traced to a problem with one of the raw materials used in its test kits, does not affect the reliability of negative results.
The F.D.A. categorized the recall, which was first announced last month, as Class I, the most serious type. Use of the tests could have “serious adverse health consequences,” the agency said. People who falsely test positive for the virus may receive unnecessary treatments for Covid-19 and experience delays in being diagnosed with and treated for “the actual cause of the person’s illness,” the agency noted…