COVID-19 rapid antigen tests are a common tool for quickly checking for the virus. A frequent concern for many is the expiration date printed on these test kits. Understanding what these dates signify and how they can change is important for ensuring test accuracy.
Understanding Test Expiration Dates
The expiration date on a COVID-19 test kit indicates the final day the test is expected to perform effectively and provide accurate results. Manufacturers determine this date through stability studies, which assess how long the test’s components remain stable. These components, such as reagents and test strips, contain antibodies designed to detect viral proteins. Over time, these parts can degrade, potentially compromising the test’s ability to accurately identify the virus. Initially, the U.S. Food and Drug Administration (FDA) authorized at-home test kits with a shelf life of about four to six months, based on available data.
How Expiration Dates Are Extended
When COVID-19 tests were first developed, initial expiration dates were often conservative due to the rapid pace of their authorization. Manufacturers continue to conduct ongoing stability studies to gather more data on the long-term performance of their tests. If these studies demonstrate that a test remains accurate beyond its original printed expiration date, the manufacturer can submit this new data to the FDA. The FDA then reviews this information and, if satisfied, authorizes an extended shelf-life for specific test lots.
These extensions allow tests to be used safely well past the date originally printed on their packaging. To verify if a specific test kit has an extended expiration date, individuals can check the FDA’s “At-Home OTC COVID-19 Diagnostic Tests” webpage. This resource lists authorized tests alphabetically and provides details on their shelf life, including any authorized extensions. Users should locate their test by manufacturer and name, then check the associated lot number against the information provided on the FDA website or the manufacturer’s own site.
What to Do with an Expired Test
Using a COVID-19 test that has truly expired—meaning it is past both its original printed date and any FDA-authorized extensions—is not recommended. The primary risk associated with an expired test is that it may yield inaccurate results, most commonly a false negative. This occurs because the test’s components, such as the antibodies, may have degraded to a point where they can no longer effectively detect the virus, even if it is present. The reliability of any result from a truly expired test is compromised.
For proper disposal of used or truly expired test kits, general household trash is usually appropriate. Most test components, including the swab and test cartridge, can be placed in a sealed plastic bag before being discarded with regular garbage. It is important to avoid flushing any test materials down the toilet or sink. For individual household use, standard waste disposal practices are generally sufficient.