Ellume, an Australian company that makes a widely available at-home coronavirus test, has recalled nearly 200,000 test kits because of concerns about a higher-than-expected rate of false positives. That represents about 5.6 percent of the approximately 3.5 million test kits Ellume has shipped to the United States.
The company, which detected the problem in mid-September, traced the issue to variations in the quality of one of the raw materials used in the test kit, Dr. Sean Parsons, Ellume’s chief executive, said in a phone interview. He declined to specify the material in question, citing a desire not to publicly disclose precisely how the test kits work.
Approximately 427,000 test kits, including some provided to the U.S. Department of Defense, were affected by the problem, Dr. Parsons said. Roughly half have already been used, he said, yielding about 42,000 positive results. As many as a quarter of those positives may have been inaccurate, Dr. Parsons said, although he stressed that it would be difficult to determine exactly how many.
“I’m very sorry that this has happened,” Dr. Parsons said. “We’re all about chasing accuracy, and to have these false positives is disappointing.”