How to Use At-Home COVID-19 Tests, According to Experts

CWhen it comes to his mother’s health, arlos del Rio isn’t slowing down. Even when he doesn’t feel sick, a day before he plans to visit her, the professor of infectious disease at Emory University in Atlanta takes a home COVID-19 test. Once he gets inside her home, the professor of infectious disease at Emory University in Atlanta tests his body again. “I want to minimize the risk that I’m infected as much as possible before I see her,” del Rio says.

It doesn’t take an infectious disease specialist to know that an 87-year-old is a high-risk person, but dual-testing the way del Rio does is not in any formal protocol for how to interact with a person of such advanced years—it’s just a practice he developed on his own. In that way, the expert is a lot like the rest of us—following a testing rule book that hasn’t really been written.

Earlier in the pandemic, home tests either didn’t exist or, when they were authorized, were hard to get your hands on as demand soared and supply lagged. There are now many options: The federal government will send several quick tests directly to your house for no cost, while insurance companies must reimburse you for eight tests each month. This allows people to stockpile them for when they are needed. How often are these tests needed? Do you need to test your self before you fly? After? When you’re visiting a home with young, unvaccinated children? Before—or after—you attend a dinner party? It is unclear at this stage if there will be any general consensus about when they should be used.

What, then, do the professionals do—the scientists who specialize in infectious diseases? To find out, TIME quizzed a few experts to determine how often they break out the tests in their own households—and when they might ask other people to test before visiting or interacting with them.

If they are experiencing symptoms

If there is any situation in which a self-test is a must-do, it’s when you or a member of your household are experiencing symptoms consistent with COVID-19. But while taking the test is an important first step, the results might not tell you the whole story, warns Thomas Briese, associate professor of epidemiology at Columbia University’s Mailman School of Public Health. Symptoms can appear before a person’s viral load is high enough for a home test to detect it.

“There is discussion about how sensitive those home tests are in comparison to a laboratory test,” Briese says. “After a negative test, I tend to re-test maybe a day or two later.” As an alternative to a second home test, he says, a PCR test is also an option, and that is Briese’s own preference, since PCR tests are more sensitive than home tests and likelier to produce a more accurate result. The downside, of course, is that a PCR test requires a visit to a clinic or testing center and results take longer—usually 24 hours or more.

What’s more, those results aren’t perfect, warns Michael Mina, former assistant professor of epidemiology at Harvard T. H. Chan School of Public Health and now chief science officer at eMed, a home testing and treatment company. If you are low in viral load, PCR testing can produce false positives. If in doubt, isolating for at least five days—as the U.S. Centers for Disease Control and Prevention (CDC) recommends—can help prevent the spread of COVID-19. Mina could extend the five-day time limit to eight days to be safe.

“There’s a wide variability in how quickly people clear the virus,” he says. “Some people will clear it by four or five days; some people will take 15 days.”

Learn More A New Test Can Help Reveal If You’re Immune to COVID-19

While traveling

COVID-19 could be more easily transmitted on trains, planes and buses because mask mandates have been lifted. Testing before you travel is one way to look out for others and make sure you’re not the viral vector in a confined space.

That may help protect your fellow travelers, of course, but it doesn’t mean that everyone is so careful, and you could wind up being not the person who spreads the disease, but the person who contracts it. For that reason, del Rio brings tests with him when he’s on the road. “When I’m traveling I’ll test myself two or three days after I arrive at my destination,” he says. “Then I’ll do the same after I arrive home.”

Mina, who is the father of a baby girl who is currently unvaccinated, is rigorous about testing the family before traveling—especially if they are visiting other people in their homes. “If we’re going to be in someone’s house, we just don’t want to be the ones who are responsible for bringing COVID in,” he says.

When socializing

Pre-pandemic, no one thought much about the health implications of a dinner party, but now that’s changed. Del Rio has made it a habit of testing his health before he invites large groups of people. This is especially true if the gathering takes place indoors. In the summer months, there are more opportunities to be outside, but SARS-CoV-2 can spread in the open air—though significantly less efficiently than it does indoors.

If you’re the host of a social event, things can be a little more delicate, raising the question of whether or not to ask your guests to test as a sort of admission ticket to your home. Here, del Rio plays it safe. “Let’s suppose we were going to have 10 or 12 people in our house: we would probably do testing,” he says. “I’d make testing available right before they came in.”

Mina is also in agreement. “We allow people to come in and we don’t make a big thing about it,” he says. “We just say keep your mask on and test right before you come in and then just let it sit for 10 minutes. We all feel a lot more comfortable knowing that everyone is negative.”

Visiting the vulnerable—the immunocompromised, the elderly, or unvaccinated babies and small children—is another area in which the experts are in agreement about testing protocols. Mina’s parents are in their 70s and, like del Rio with his 87-year-old mother, he tests before visiting them. Briese tests before visiting anyone with any medical condition, even if he doesn’t know if the person is immunocompromised. Although vaccines can be given to babies as early as six months of age, the uptake will likely slow so testing is recommended before any visit.

Learn More Study suggests that dogs can detect COVID-19 in their surroundings and signs of long COVID.

During surges

It pays to pay attention when COVID-19-related cases are increasing. Mina, his family, and others tested for COVID-19 symptoms on an average of once every week in the last surge.

Briese views children as an area of special concern, because they often spend time in school with so many kids. Even if there is no known case of COVID-19 in a child’s social circle, the risk of transmission exists—especially during a surge. “It might make some sense to test children on a more regular basis,” he says.

That said, if you have a limited number of tests, you shouldn’t necessarily test immediately after a known or suspected exposure to someone who is infected. “If you’ve just been exposed, don’t even bother testing for two days,” says Mina. “Wait at least that long, but often you have to wait three days—if not four—post-exposure [to get an accurate result] because the virus has to have a chance to become detectable.”

Experts agree that testing is an individual decision and each person must determine their risk tolerance and comfort levels. The goals for everyone should be the same, which is to avoid both the spread of the virus and contracting it. Anti-COVID-19 tools include key components such as masking the symptoms and keeping up to date with vaccinations. It is also important to have rapid testing.

Read More From Time

Send an email to Jeffrey Kluger at


Related Articles

Back to top button