If you’ve been stockpiling COVID-19 test kits in your cabinet, or recently received your free tests from the government, you might want to take note of their use-by dates, as most kits expire within a year.
But even if your kit’s expiration date is approaching, that doesn’t necessarily mean it’s time to trash it. Most of the expiration dates initially listed on the packaging labels were a prudent estimate based on preliminary stability tests. Over the past couple of years, additional testing has been conducted to determine the true shelf life of the various at-home tests, and, as a result, many test manufacturers have updated their products’ expiration dates.
That said, you’ll still want to be mindful of how long your kit is good for. Using a kit that’s well past its expiration date could lead to inaccurate results that could give you a false sense of security.
“Then you could make decisions based on something that’s no good,” said Cedric Yansouni, a scientist at the Infectious Diseases and Immunity in Global Health Program at the Research Institute of the McGill University Health Centre.
How quickly the COVID at-home rapid tests expire
The expiration dates vary from brand to brand, but generally range from six months to 15 months from the time they’re manufactured. Abbott’s BinaxNOW kits along with Ellume’s COVID home tests have a 15-month timeline; the orange iHealth kits are good for nine months.
These expiration dates are based on stability tests the manufacturers conducted during development to estimate the kits’ shelf lives. But the expiration dates initially listed on the kits’ packaging labels are most likely conservative.
“Typically, when you first market a new product, you’re going to be putting out a best-before date or expiry date that you know, for sure, will cover the period during which the product will give you reliable results,” Yansouni said.
Eventually, certain rapid test ingredients ― like the solution in the droppers ― start to go bad. The whole idea behind the expiration dates is to ensure these components still work well so the tests provide accurate results, which helps people make informed decisions about their health.
“The worst thing that can happen is being falsely reassured or falsely alarmed by a test result that was based on a reagent that is no longer valid,” Yansouni said.
Expiration dates are changing
Keep in mind that the rapid antigen tests for COVID-19 are relatively new and have only been around for a couple of years. Though the initial stability tests helped manufacturers bring the test to markets quickly, determining the tests’ true shelf life takes time, as manufacturers must evaluate how the tests hold up over weeks, months, and maybe even years.
Over the past two years, test manufacturers and government agencies have continued to test the kits’ durability and have updated various test kits’ expiration dates based on their newer findings.
The BinaxNOW kit, for example, was originally marketed with a 12-month shelf life that has since been extended to 15 months. Similarly, the iHealth kits started with a six-month expiration date that was recently increased to nine months. For both of these kits, you can add three months to the expiration date listed on the box. Ellume currently has a 15-month shelf life, and a 21-month shelf life is currently under review, according to an Ellume spokesperson.
To see if your test kit’s expiration date has been recently updated, visit the Food and Drug Administration’s page on diagnostic tests. Scroll down to the table of tests and enter “OTC” in the search bar. Then, find the test you are looking for, click on the + symbol to the left of the kit name, and look for a letter granting EUA revisions. You can also call the test kit manufacturer, such as Abbott Diagnostics or Ellume Limited, and ask if they’ve updated the expiration date of your specific kit.
Yansouni expects that, eventually, the at-home kits could have a shelf life of up to 24 months, as that’s pretty typical of rapid diagnostic antigen tests used for other health conditions.
Can you use a COVID test kit after its expiration date?
Yes, but with some considerations.
Sheldon Campbell, a lab testing expert at Yale Medicine and professor of pathology at Yale School of Medicine, said if a test was only a week or so past its expiration date, he’d probably use it. That’s “with the caveat that if it was negative and I really was afraid that I had COVID, then I’d get retested. And if it was positive, then I’d probably call that a positive,” Campbell said, adding that he’d discard them shortly after their expiration date.
If the test result is important to you, you probably want to be confident in the result and use a kit that hasn’t expired. If you use a kit well past its most recently updated expiration date, you run the risk of getting an inaccurate result. (False negatives are more common, but false positives do happen.)
“The only thing worse than no result, is a result that’s lying to you,” Campbell said. “Don’t use one that’s six months outdated.”
How to properly buy and store at-home COVID tests
If you get your kits from a local pharmacy, try to find kits with a later expiration date so you can hold onto your kit for a bit longer.
Even if you’re within the expiration date, the kits are only valid if they’ve been stored adequately — a detail that’s often overlooked. The kits can quickly go bad if they end up in a very cold or very warm environment. (You want to store it between about 40 and 86 degrees Fahrenheit.)
“Even in a car on a sunny day for a couple of hours, you could ruin your whole box of tests,” Yansouni said. And there’s not really a way for you to tell if an at-home test is no good.
Campbell recommended being intentional about when you order your kits, as you don’t want them sitting on a mail truck in the dead of winter when they could freeze and thaw out or in the peak summer months when they could bake in the heat.
Once you receive a test kit, make sure the package is sealed and hasn’t been previously opened and has a moisture-absorbing bag of crystals (silicon) ― humidity is a test killer. Check the expiration date, and if your kit’s date has passed, visit the FDA’s website to see if the date has been extended. If it hasn’t, your test result will not be reliable.
“You’re better off using something else,” Yansouni said.
Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.