They have a fever, cough and feel exhausted – symptoms common with COVID-19. You want to take a test at home, but when you pull one out of your medicine cabinet, you realize it’s expired.
What should one do? Is it OK to still use an expired COVID-19 test? Are expired COVID-19 tests accurate?
Microbiologist and pathologist Daniel Rhoads, MD explains why COVID-19 testing is done at home and what results you can get if you use one.
Do COVID-19 tests expire?
Yes. Rapid at-home COVID-19 tests are expiring. These home tests are used to take a sample from your nose to measure it against COVID-19 antibodies stored in the test strip.
While certain parts of the at-home testing kit, like the swab, don’t expire, there are parts like the vials of liquid and test strips that do.
“The test contains SARS-CoV-2 antigen-specific antibodies – this is what the test relies on for its reliability. The antibodies in the test capture the antigen that is part of the virus,” explains Dr. Rhoads. “So these antibodies can go bad over time. They’re little pieces of protein, so they can degrade over time.”
If there is liquid in the test, it can potentially evaporate over time, meaning you don’t have enough liquid volume to perform the test properly.
Do expired COVID-19 tests work?
So can you use an expired COVID-19 test?
First of all, it is important to make sure that your test is at home Strictly speaking Expired.
“The expiration date listed on the packaging may not match the actual expiration date,” notes Dr. Rhoads. “When manufacturers first released these tests, they had conservative expiration dates. If they conduct additional studies and show that the expiration date can be pushed back, they can extend it. But the boxes have already been distributed, with the original expiration date already written on them.”
To check the expiration date of your COVID-19 test, Dr. Rhoads to review it on the US Food and Drug Administration (FDA) website. It lists the manufacturer’s name, the name of the test, and any extended expiration dates. In some cases, you can compare lot numbers from a home test box to the list. Many tests have had their expiration dates extended from 15 to 22 months.
If you have a test with an extended expiration date, your test should work and give you accurate results. But if you have an expired test, says Dr. Rhoads that the FDA advises against using it to determine if you have COVID-19 because the results may not be accurate.
Does an expired COVID-19 test give a false positive result?
“Scientifically, it makes no sense to get a false positive result with an expired test,” says Dr. Rhoads. “The concern would be that you would get a false negative. If the antibodies also stop working, the test may not detect the virus as well as it did when it was originally made.”
If you have symptoms or have been in close contact with someone who has COVID-19, you should either use an unexpired home test or get a polymerase chain reaction (PCR) test.
How to keep your COVID-19 tests at home
You want to store your COVID-19 tests at home in a dry place – and keep your tests in their original packaging.
“They’re usually pretty well packaged, but I’d keep them where you keep your meds in a cool, dry place,” advises Dr. Rhoads.
This is important as factors such as extreme heat or cold can affect results. And you want to keep tests at home out of the reach of children and pets.
Whether you want to stock up on home tests or get one whenever you need to test it is entirely up to you.
“If you feel like testing on short notice, have one on hand,” encourages Dr. Rhoads.
If you have symptoms or have been in contact with someone who has COVID-19, the FDA recommends testing more than once and every few days if you use antigen testing.
Knowing for sure if you have COVID-19 can help you prevent the virus from spreading to others and also help your healthcare provider choose the best COVID-19 treatment or treatment strategy for you.
But overall, the best defense against severe COVID-19 is to get vaccinated and keep up to date with all booster shots recommended by the US Centers for Disease Control and Prevention (CDC).