Everything you need to know about rapid, at-home COVID-19 tests

At-home COVID-19 tests, also known as rapid antigen tests, are convenient and accessible. But be careful. The test results often are wrong. Learn when and how to use the tests.
Jan. 24, 2022
Rapid, at-home COVID-19 tests are convenient. But be careful about relying on them. The results are often wrong. Learn more about how to use at-home COVID-19 tests. Photo: Getty Images.
Rapid, at-home COVID-19 tests are convenient. But be careful about relying on them. The results are often wrong. Learn more about how to use at-home tests. Photo: Getty Images.

 

Millions of Americans are ordering free at-home COVID-19 tests now and these rapid tests soon will be arriving in mailboxes.

Ordering the tests takes less than a minute. You simply click on the turquoise button on the popular new covidtests.gov website. Then you fill in your address and the free at-home COVID-19 tests should arrive within a week or two. For now, each household in the U.S. is entitled to four free at-home COVID-19 tests. 

Easy, right? 

How to get four free rapid at-home COVID-19 tests

  • Visit the website, covidtests.gov
  • Click on the turquoise button to order your free at-home COVID-19 tests. No ID, credit card or health insurance information is required.
  • If you need help, call 1-800-232-0233 (TTY 1-888-720-7489).
  • At-home tests may also be found at local stores, though availability and supplies have been limited.

Well, ordering the tests is quick and easy. But figuring out when and how to use them or how to understand your results is not so simple. That’s because at-home COVID-19 tests — also known as rapid antigen tests  — are not as accurate as the much more reliable nasal swab PCR tests. PCR stands for polymerase chain reaction. (Learn more about getting PCR tests. UCHealth does not offer rapid antigen tests since they are much less accurate.)

The appeal of at-home COVID-19 tests is the convenience and accessibility. You can take the test at home (hence the name) and you can get a result within about 15 minutes. But it’s important to be cautious about rapid, at-home test results and how you use them. They might be appropriate to use in some cases. But they are not free passes to prove you don’t have COVID-19.

To help you understand what at-home COVID-19 tests are and how to interpret any results you get, we spoke with Dr. Michelle Barron, senior medical director of infection prevention and control for UCHealth and a professor of medicine and infectious diseases at the University of Colorado School of Medicine.

What is an at-home COVID-19 test?

The at-home tests detect proteins on the virus that causes COVID-19. These proteins are called antigens and that’s why at-home rapid tests are known as antigen tests or rapid tests. They do not have to be sent to labs in order to get results. Usually, people can see their results in about 15 minutes. PCR tests, on the other hand, test for the genetic material of the active virus. The samples from these tests need to be analyzed in labs. That takes several hours (at a minimum) and up to a few days depending on how busy labs are.

Are at-home tests reliable?

At-home tests are accurate about 80% of the time. While 80% sounds decent for a grade on an algebra test, it’s not great for a COVID-19 test. It means that 20% of the time — or 1 in 5 times to drive the math home — when a person is infected with COVID-19, the test is not picking up evidence of the virus. This is known as a false negative result. And, if people use false negative results from rapid at-home tests incorrectly, they can endanger high-risk individuals like older adults, people with cancer or those with compromised immune systems.

That’s why Barron and other medical experts are urging people to be cautious about the tests.

Here is Barron’s basic guidance about interpreting results from at-home COVID-19 tests:

  • Do not assume that a rapid, at-home test is accurate if you are feeling sick and you get a negative result.
  • Do not assume that a rapid, at-home test is accurate if you have been in close contact with someone who has received a positive COVID-19 test result and you are feeling sick. Especially with the highly contagious omicron variant that easily spreads from person to person, if you were in close contact with someone who tested positive for COVID-19 and you have any symptoms, it’s highly likely that you have COVID-19.
  • Do assume that a positive result from an at-home test is accurate. If your rapid antigen test says you have COVID-19, you probably do. False positive results are not very common with at-home COVID-19 tests, Barron says.

“Use your common sense,” Barron says. “Do not use a negative result with an at-home test as a free pass to go out if you have symptoms. If you have a sore throat, a runny nose, a headache or any of the other symptoms of COVID-19 and you get a negative test result, you probably have COVID-19 and the test is missing it.”

Barron encourages people to continue using safety protocols that have worked for two years and to be conscientious and kind. Wear masks in crowded, indoor places. If you have symptoms of an illness, whether you think it’s COVID-19, the flu or just a cold, stay home and don’t infect others. People who are sick should not show up at work, go to the gym, fly on a plane or attend a social gathering.

While Barron continues to be an optimist, she must underscore what omicron has made obvious.

“We’re not done with this pandemic yet,” Barron said.

So, she urges people to please protect their family, friends and community members. Think about vulnerable people like older adults, immunocompromised people, pregnant women and young children who haven’t been able to get vaccinated yet.

If I test positive for COVID-19 on an at-home test, is it likely that the result is correct?

Yes. A positive result on an at-home COVID-19 test is likely accurate.

If I test positive on an at-home COVID-19 test, do I need to get a PCR test to confirm my positive test?

No. If you test positive, you can assume you have COVID-19.

What should I do if I test positive using an at-home COVID-19 test?

Why are there so many false negative results with at-home COVID-19 tests?

At-home COVID-19 tests produce a high percentage of false negative results because they are less sensitive than PCR tests. PCR tests are accurate nearly 99% of the time. Antigen tests don’t pick up all COVID-19 infections, but timing is also important. People sometimes test negative because they take the rapid at-home test too soon during the course of their illness. Or, it’s possible that they are not correctly swabbing themselves.

How do you take an at-home COVID-19 test?

Follow the instructions on your at-home test. Typically, at-home tests require people to swab their noses to get a sample. Since at-home COVID-19 tests have been in short supply around the U.S., there have been reports of families sharing a single at-home test. Do not do this. The tests won’t work and it’s unsanitary to use a single swab on multiple people.

Do at-home COVID-19 tests expire?

Yes. The rapid tests do expire. Experts from the U.S. Centers for Disease Control and Prevention caution people not to use antigen tests that have expired. Learn more.

If you think you have COVID-19 or you were exposed to someone who got a positive test result, what is the best time to take an at-home rapid test?

  • If you do not have symptoms, wait about five days before taking an at-home test.
  • If you do have symptoms and you were exposed to someone with a confirmed case of COVID-19, you can assume you also have the illness since it’s so contagious and omicron is so widespread. If you are assuming you have COVID-19, isolate yourself so you don’t spread the illness.

“Wait at least 72 hours and ideally five days to get tested unless you have symptoms,” Barron said.

The reason she recommends waiting to take a test (unless you have symptoms) is because tests can’t immediately pick up COVID-19 infections.

“Say I had COVID-19 and I coughed on you. You’re not suddenly going to be positive in an hour. With omicron, the infection ramps up more quickly. But, it’s not overnight. It still takes a couple of days,” Barron said.

If you have symptoms, you can go ahead and get a test or simply assume you have COVID-19 and behave accordingly.

“If you have symptoms, you are more likely to have COVID-19 than anything else,” Barron said.

Who should get COVID-19 tests?

People who are at high risk for suffering from severe consequences if they get COVID-19 should get tested. Other people may need to get tested for their jobs, school or before taking a trip.

People who are having medical procedures usually need to get a COVID-19 test. Health care facilities generally do not accept results from at-home rapid tests, so in those cases, people will need to go to a PCR testing facility. 

Both PCR and rapid, at-home COVID-19 tests have been harder to get this winter. 

People with common symptoms of COVID-19 may want to get tested. By now, the symptoms of the illness are quite familiar, but they include the following: fever, shortness of breath, a new cough, fatigue, muscle or body aches, headache, new loss of taste or smell, sore throat, congestion or runny nose, nausea or vomiting or diarrhea. Of course, these symptoms are also similar to the flu.

In general, if you are sick, stay home and don’t spread your illness to others. If you need to confirm whether or not you have COVID-19, the most reliable test will be a PCR test. 

When might it make sense to use a rapid at-home COVID-19 test?

If you’re having a family birthday party and an older relative will be there, the first step is to ensure that everyone who is coming is fully vaccinated and boosted (assuming they are eligible).

Then, you need to discuss in advance if anyone is feeling sick. Anyone who has any symptoms of illness should not attend any kind of gathering. And, with high rates of COVID-19 continuing to spread in communities, it’s best not to have large gatherings now.

If you’re hosting a smaller gathering of vaccinated people, after screening out those who are sick, you could consider having everyone take a rapid test before coming to the party. But, it’s important to know that the results won’t guarantee that every guest is negative for COVID-19. And, you shouldn’t use those results to determine whether or not it makes sense to have someone vulnerable attend the party. You have to weigh potential risks and decide what makes sense

Barron cites an example from her family. About two days after getting together with her parents, a relative tested positive for COVID-19. The family members all were vaccinated and had been wearing masks at a public event. Barron’s parents asked whether they should get tested right away. Barron encouraged family members to monitor for symptoms and wait at least 48 hours to get tested. If the family members took a rapid at-home test, that meant they had COVID-19. But, a negative result on a home test did not mean they didn’t have it.

In the meantime, she told her parents to skip normal activities that involved crowds.

“You don’t want to go to the YMCA and do a dance class with a bunch of older people,” Barron said.

About five days after exposure or if they had developed symptoms, it would make sense to get tested, preferably with a PCR test, Barron said.

What are the benefits of rapid, at-home COVID-19 tests?

One of the biggest potential benefits of rapid, at-home tests is accessibility, Barron said. Going to a testing facility and waiting in line if it’s crowded takes time. For some people, it’s difficult to take a couple of hours off from work. For older people, the logistics can be challenging.

For people in rural areas, testing sites can be far from home.

Having tests mailed directly to every address in the U.S. will be a big convenience for many people. But four tests won’t last long for each household. And, Americans should be aware that false negative results are common. 

“Use the tests wisely. Know the limitations of what they can and can’t do,” Barron said.

I hear rapid, at-home COVID-19 tests are most reliable when people use them regularly, like twice a week. Is that true? 

Yes. Since at-home tests are less accurate, you’re more likely to pick up an infection if a person takes an antigen test on a regular basis. Some universities and employers have regular testing programs. But since supplies of rapid, at-home tests are low, it doesn’t make sense for most people to take at-home COVID-19 tests frequently. For now, you’ll want to think carefully before using an at-home test.

Is it true that with an at-home test, you could test negative in the morning and positive later that same day?

Yes. All COVID-19 tests can only give results that amount to a snapshot in time.

That’s why it makes sense to wait to take a test either until you have symptoms or until about five days after you’ve been exposed to someone who has tested positive to COVID-19. Taking a test immediately after an exposure doesn’t do much good. 

“You’re just trying to reassure yourself without actually reassuring yourself,” Barron said.

Is it likely that we might all keep at-home COVID-19 tests on hand in the future?

Yes, it’s possible. Barron envisions a time when we all might keep at-home COVID-19 tests in our medicine cabinets, just like we keep thermometers around.

She cites examples of precautions we now take without thinking about them. For example, people regularly use seatbelts in cars now compared to many years ago when children just piled into the “way, way back” of station wagons and rode around unprotected.

In the post-9/11 world, we regularly take our shoes off at airports to make planes safer.

Similarly, to ensure that we are well, we might someday take rapid, at-home COVID-19 tests before heading out to parties.

“These tests are not perfect. But, they may be a way to mitigate infections in the future. If grandma or someone with cancer is visiting, we will want to be careful,” Barron said. “These protocols may be part of our DNA forever.”

Can Americans living outside the U.S. order the four free rapid, at-home tests?

People who are serving overseas in the military and the diplomatic corps can get the four free at-home tests. Those living in U.S. territories are also eligible.

What brand of test will people receive?

As the old saying goes, “you’ll get what you get.” With the federal program, you won’t be able to select a brand for the free tests that you received. But all of the rapid antigen tests that federal officials will be shipping are fully authorized by the U.S. Food and Drug Administration or FDA.

How will the tests be delivered?

Workers with the U.S. Postal Service will be delivering the four free tests to U.S. households. The tests are slated to arrive about 7 to 12 days after you place your order.

If I have health insurance, I hear that there’s a separate program where I can get reimbursed for at-home tests. Is this true?

Yes. It’s true for some health insurance plans. As of Jan. 15, federal health officials are requiring most private health insurance companies to reimburse people for up to eight rapid, at-home tests each month. This program is separate from the federal effort to supply each American household with four free rapid at-home COVID-19 tests. It’s still difficult to find the rapid tests in stores. And different insurers are handling reimbursements for rapid COVID-19 tests differently, according to an analysis from the Kaiser Family Foundation showed. If you have questions about how to get rapid tests through your health insurance plan, call your insurance company.

Is it true that some states provide free at-home COVID-19 tests to individuals?

Yes. Check with public health agencies in your state and learn more about Colorado’s program to provide rapid, at-home tests to people.

About the author

Katie Kerwin McCrimmon is a proud Colorado native. She attended Colorado College, thanks to a merit scholarship from the Boettcher Foundation, and worked as a park ranger in Rocky Mountain National Park during summer breaks from college. She is also a storyteller. She loves getting to know UCHealth patients and providers and sharing their inspiring stories.

Katie spent years working as a journalist at the Rocky Mountain News and was a finalist with a team of reporters for the Pulitzer Prize for their coverage of a deadly wildfire in Glenwood Springs in 1994. Katie was the first reporter in the U.S. to track down and interview survivors of the tragic blaze, which left 14 firefighters dead.

She covered an array of beats over the years, including the environment, politics, education and criminal justice. She also loved covering stories in Congress and at the U.S. Supreme Court during a stint as the Rocky’s reporter in Washington, D.C.

Katie then worked as a reporter for an online health news site before joining the UCHealth team in 2017.

Katie and her husband Cyrus, a Pulitzer Prize-winning photographer, have three children. The family loves traveling together anywhere from Glacier National Park to Cuba.

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