Many individuals use at-home COVID-19 tests for quick answers. These tests are often stored for extended periods, leading to questions about their continued effectiveness. This article clarifies how expiration dates, test mechanisms, and official guidance determine the usability of your tests.
Understanding Test Expiration Dates
The expiration date on a COVID-19 test kit indicates the final day the manufacturer expects the test to perform accurately and effectively. This date is determined through stability studies, which assess how long test components maintain their integrity under specific storage conditions. You can typically locate this date on the test kit’s box.
Manufacturers initially set these dates based on data available at authorization, often resulting in shorter shelf lives of four to six months. This date ensures the test produces results as accurate and reliable as when first manufactured.
Why Expiration Matters for Test Accuracy
A COVID-19 test’s reliability is closely tied to the stability of its internal components. At-home antigen tests rely on specific reagents, such as antibodies, that bind to viral proteins to produce a visible result. Over time, these biological materials can degrade, reducing the test’s sensitivity and specificity.
When test components degrade, an expired test might not accurately detect the SARS-CoV-2 virus, even if present. This can result in a false negative, meaning the test indicates no infection when one exists. The liquid in the test vial can also evaporate, potentially leading to insufficient sample volume. Using an expired test carries the risk of obtaining an unreliable result, which could lead to unknowingly spreading the virus.
Official Extensions for Test Shelf Life
Many COVID-19 at-home tests have received shelf life extensions from regulatory bodies like the U.S. Food and Drug Administration (FDA). These extensions are granted when manufacturers provide additional stability data, demonstrating tests remain accurate and effective beyond the initially printed expiration date. The FDA reviews this data, and if evidence supports a longer shelf life, the expiration date is officially extended. This means a test might still be usable even if the date on the box has passed.
To check if your specific test kit has an extended expiration date, visit the FDA’s website. It maintains a list of authorized over-the-counter COVID-19 diagnostic tests. Find your test’s brand and lot number, usually near the printed expiration date on the box. The FDA’s list provides updated expiration dates for specific test lots, sometimes extending them by several months or up to two years. If your test’s lot number is listed with an extended date, you can rely on that new date.
What to Do with Your COVID Tests
Before using a COVID-19 test, locate the expiration date on the kit’s box. If this date is in the future, the test is fine to use. If the printed date has passed, check for any official extensions.
Visit the FDA’s website and use the search function to find your specific test brand and lot number. If your test has an extended expiration date, you can use it until that new date. If your test’s lot number is not on the FDA’s list, or if the extension has also passed, dispose of the test, as its accuracy cannot be guaranteed.
Proper storage conditions also influence a test’s shelf life. Keep tests within the recommended temperature range specified on the packaging to prevent component degradation. If you use an expired test and receive a negative result, especially with symptoms or known exposure, retest with a valid, unexpired kit or consult a healthcare provider.