The government is once again offering free at-home COVID tests. If you saved some from the last time they were issued, now would be a good time to double-check their expiration dates.
Most of the over-the-counter SARS-COV-2 tests look for the antigen found on the virus. That’s the protein coating, and it uses antibodies to do that, explained Dr. Daniel Rhoads, a microbiologist for Cleveland Clinic.
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So, over time, those antibodies can kind of wear out. They can degrade. Just like food in your cabinet has an expiration date, the tests have an expiration date.
Rhoads said if a person uses an expired COVID test, they risk getting a false negative even if they are actually sick.
However, the opposite is true for a false positive.
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If the expired test shows a positive result, it’s typically accurate.
Now, before you go and throw away any old tests you have sitting around, he suggests visiting the FDA’s website first.
The federal agency created a page where you can look up whether your COVID test has an extended expiration date.
A lot of the expiration dates have been lengthened beyond what’s printed on the package because the companies that make them do studies, and they show over time, if the test holds up, that they can extend that expiration date beyond the initial expected expiration, Rhoads explained.
And the same goes for the new at-home COVID tests being issued.
The government notes the box may say expired, but they’re still okay to use since the expiration dates were extended.