The U.S. Food and Drug Administration is advising consumers to stop using and throw out certain lots of Pilot COVID-19 At-Home Test kits.

The FDA has significant concerns of bacterial contamination in the liquid solution provided in the test kit.

Direct contact with the contaminated liquid solution may pose safety concerns, and the bacterial contamination could impact the performance of the test, according to officials.

In the U.S., approximately 500,000 tests were distributed to CVS Health, and about 16,000 tests to Amazon by Roche Diagnostics. The FDA is working with Roche Diagnostics to understand how many of those tests were sold to consumers.

None of the impacted lots were distributed through COVID.gov/tests or as part of other federal testing programs.

To see the lot numbers affected, click here.