As COVID-19 cases rise across the country, you may be tempted to pull out one of the leftover rapid at-home tests you received from the Biden administration months ago.
Even if the packaging says the tests are past their expiration date, you may want to think twice before throwing them away, experts told ABC News.
They say the expiration date may have been extended by the federal government and they could come in handy if you need them in an emergency.
How is the expiration date for a home COVID-19 test determined?
The expiration date is set by the manufacturer, typically the shelf life is approximately four to six months from the date of manufacture, which is then approved by the US Food and Drug Administration.
dr Matthew Binnicker, director of clinical virology at the Mayo Clinic, told ABC News that expiration dates were set conservatively at the start of the pandemic because it was unknown how long they would be effective.
“Now that we have been affected by the pandemic for over three years, manufacturers have had a better opportunity to determine the actual expiry date of these kits,” he said.
“And the FDA has actually published extended expiration dates based on additional data from manufacturers, so the expiration date listed on a test or box of antigen tests may not be the actual expiration date. People should go to the FDA website,” Binnicker said.
To check for an extended expiration date, visit the FDA home testing webpage. The brands that have an extended expiration date are listed there, and there is a PDF file with new expiration dates for each test.
You can find the lot number on the package near the expiration date and then check the PDF to see if it falls within those dates.
What does it mean when my test has expired?
If you confirm that a home test has expired and has not been renewed, it is best to find a new COVID test that still has an existing shelf life.
However, this does not mean that it cannot be used.
“The further away you are from the expiration date, the less likely it is to work exactly as you expected. “That’s why you should perhaps be a little more suspicious,” says Dr. Emily Landon, associate professor of medicine at UChicago Medicine, told ABC News. “But honestly, I don’t think there’s anything wrong with using a test that’s a little past its expiration date.”
She said if the test produces strange results — such as if the liquids used in the test look cloudy or a first line doesn’t appear — those tests should be thrown away. But it might be helpful to use in an emergency.
“But if you have old tests, I certainly think using old tests is better than not using any tests,” she said.
Binnicker added: “If so [used an expired test] and you get a positive result, it will usually be a reliable result. If it is negative, it may not be reliable.”
Do old tests work against the new variants?
The FDA and experts say older home tests are capable of detecting COIVD infections caused by new variants, most of which are Omicron offshoots.
What sets most newer variants apart are mutations in the spike protein that the virus uses to enter and infect cells, Binnicker explained.
But “the antigen tests typically look for another protein in the virus, the nucleocapsid protein,” he said. “The available data therefore suggests that the antigen test should continue to be effective in detecting the newer circulating strains.”
When should I test for COVID-19?
If you experience symptoms, experts recommend getting a COVID test immediately.
For people who have recently been in contact with someone who has tested positive, you should get tested five full days after your last interaction with the person, according to Centers for Disease Control and Prevention guidelines.
If you plan to come into contact with people who may be at high risk of serious illness, such as the elderly or people with weakened immune systems, you might choose to get tested, the experts say.
“The most important thing to remember is that if you have symptoms or have a respiratory virus, you really need to stay away from others or wear a mask when you are around them,” Landon said.
If positive, try to stay home, isolate yourself from others and contact your doctor.
Binnicker said that a person with a positive rapid test and symptoms does not need a confirmatory PCR test, but that it may be helpful for a person with a positive test who is asymptomatic.
I received a negative test result from a home COVID-19 antigen test. Do I need to take another test?
Despite a negative test, you may want to test again in the coming days because some tests may not detect the virus early in an infection.
Try to get tested 48 hours after your first negative test if you have symptoms. People without symptoms should be tested 48 hours after the first negative test and then 48 hours after the second negative test.
“This is where I think the mistake most people make is that they think the testing is less reliable because it takes until the second or third day of symptoms for them to have a positive test,” Landon said. “But that is expected… The home tests are not intended to detect the very first signs of COVID. You should be able to tell whether your respiratory illness is COVID or not.”