You've probably seen at-home COVID tests, often called "rapid tests," in your local drugstore. They can detect infectious coronavirus cases without the need for PCR testing at the doctor's office. But how do you use these at-home tests, and can you trust the results for children? Here's everything parents need to know.
Types of At-Home COVID-19 Tests
When it comes to COVID-19 tests, most parents are familiar with PCR (polymerase chain reaction) varieties. These "molecular" tests are given in a doctor's office or testing center to diagnose a current coronavirus infection. They search for small amounts of viral RNA—often through a sample taken with a nasal swab. The sample nearly always needs to be processed in a lab, so it usually takes at least 24 hours to get the results. PCR tests are considered the "gold standard of COVID-19 testing," says Jeffrey S. Dlott, M.D., MS, senior medical director, Medical Affairs, Diagnostic Services at QuestDirect and Quest Diagnostics.
As the pandemic continues, more companies are releasing rapid COVID tests that can be taken at home. There are two main types: over-the-counter rapid antigen tests and at-home collection kits.
The main type of home COVID test that parents will encounter is called an antigen test. These tests look for virus proteins and typically return a result in about 15 minutes (hence why they're also called rapid tests). The entire process is done at home, which is extremely convenient for busy parents. However, as a downside, some individuals may struggle with following the directions and performing the test, leading to inaccurate results, says Dr. Dlott. "Additionally, rapid antigen tests are typically less sensitive than molecular tests. "
When they're in stock, antigen tests like the BinaxNOW by Abbott are available at major retailers like Walmart, CVS, Walgreens, Amazon, and Rite-Aid. Other manufacturers include Becton Dickinson, Ellume, OraSure and Quidel. The full list of antigen tests approved under emergency use authorization is available from the Food and Drug Administration (FDA). They typically cost about $20 to $35 each.
At-Home Collection Kits
You can also schedule an at-home PCR sample collection through a service like QuestDirect, a part of Quest Diagnostics. The sample collected at home is then mailed into a lab for processing, says Dr. Dlott. Patients using this option can be "confident that their tests are the same high quality molecular test ordered by their physicians, but with the convenience of specimen collection in their home," he adds. After the lab receives the sample, patients generally get test results in one or two days. These at-home collection tests cost $100 or more.
NOTE: Antigen tests and molecular tests are diagnostic tests used to determine a current COVID-19 infection. Antibody tests are also available, but these indicate a previous infection or vaccination response, says Wendy Sue Swanson, M.D., MBE, FAAP, pediatrician and Chief Medical Officer at SpoonfulONE. These are usually blood tests and can't be done at home.
How to Take an At-Home COVID Test
It's important to follow the directions on your at-home COVID-19 test carefully; otherwise, you might receive a false result. Samples for diagnostic tests are typically collected with a nasal or throat swab, or saliva gathered by spitting into a tube, notes Dr. Swanson.
How to Take Antigen Tests: For most over-the-counter rapid antigen tests, parents must insert a nasal swab into their child's nose and move it around for several seconds. Then they'll put the snotty swab into a reservoir of test reagent and wait. Results will be similar to a pregnancy test—a digital reading or lines indicating a positive or negative diagnosis, says Dr. Swanson.
How to Take At-Home Collection Tests: These will include a tool (likely a swab) for collecting the sample. The kit will also have "a tube with a stabilizing material as well as detailed shipping information" for sending the sample to the lab, adds Dr. Dlott.
Are At-Home COVID Tests Accurate?
Antigen tests are less sensitive than PCR tests, which doesn't mean they're worse. A PCR test will pick up very low levels of viral RNA, and a person might show a positive PCR test for weeks, or even months, after having recovered from COVID-19. That's why the CDC doesn't recommend testing for people who have had COVID-19 in the past 90 days unless they start showing symptoms again.
It's useful to think of antigen tests as "contagiousness tests," Michael Mina, M.D., Ph.D, an associate professor of epidemiology at the Harvard T.H. Chan School of Public Health, has said throughout the pandemic, most recently in a op-ed for The New York Times arguing for wider use of the tests. For people with symptoms, antigen tests work exceptionally well.
PCR tests are incredibly sensitive, so they're useful for confirming an infection after a positive antigen test. They're highly unlikely to return false negatives, so a positive antigen test followed by a negative PCR test means that the first result was likely an error. The goal of testing is to identify cases as soon as possible so people can avoid exposing others, and antigen tests are great tool for accomplishing this, assuming they're available.
At-home collection kits usually rely on PCR tests, so they're more accurate than the antigen varieties.
When Should My Child Take an At-Home COVID Antigen Test?
Because at-home antigen tests are easy to use and return results quickly, they're ideal for situations that don't allow for PCR tests. For instance, rapid antigen tests can be used before entering an event like a wedding, seeing an elderly family member, or going to school after an exposure. That strategy, called test-to-stay, has been adopted in the United Kingdom and Massachusetts as a way to reduce student quarantines.
Ideally, you'd use an antigen test for surveillance testing of asymptomatic infections, or any time a person in the household has any COVID symptoms, including a sore throat, fever, or runny nose. In practice, these tests have been hard to come by in the United States, and they tend to be expensive, so few private citizens have the means to do this.
Dr. Swanson suggests testing repeatedly after any high-risk behavior, such as attending a crowded or indoor event. "Testing at home is a great way to protect your family and others. The more we test, the more we know where COVID infections, especially those that are asymptomatic, arise," she says. "After any high-risk behavior (crowd, indoor and unmasked, travel, etc.) I strongly recommend testing multiple times over the seven to ten days afterward. At-homes tests can make that more likely."
At-home collection kits have a higher degree of accuracy than antigen tests, but you need to wait longer for results. These can indicate COVID-19 infection if you aren't rushed for a diagnosis; for example, if your child is symptomatic and staying home from school anyway, and you'd rather not bring them to a doctor's office for testing. Always consult your pediatrician for advice.
Can My Kids Swab Their Own Noses?
The specimen for an at-home test is often taken from the front part of the nose, not the back like early testing required. Parents may need to swab their young child's nose to ensure a good sample (or have another parent or caregiver assist), but kids age 3 and up can learn to take their own samples, which also helps them feel more in control of the process, says Shawna Marino, an adviser to Dr. Mina's home PCR testing startup. This is often what older kids do if they're tested at school as part of a surveillance testing routine.
No matter what, it's important to be upfront about the testing process with your child. "It's not 'painless' because the swabs are truly uncomfortable, but the discomfort is very temporary and only lasts the five to ten seconds you need to get the sample," says Dr. Swanson. "The specific steps are different for each test—parents can remain calm, keep a positive attitude while doing it, share truthful expectations for their child, and both provide distraction (a super fun game or show) and rewards (like ice cream) when completed."
Can I Use An At-Home Test on Babies or Toddlers?
While the official guidelines discourage at-home tests for those under 2, Marino says that parents should check with their pediatricians. She uses antigen tests off-label to test her 15-month-old and has done so since 12 months. Not every PCR testing site will test kids, and those that do often have shorter hours than general testing sites.
What Happens If My Kid's At-Home COVID Test is Positive?
What if your child's at-home COVID test comes back positive? Isolate them and assume they have COVID-19, especially if you take a second rapid test that also comes back positive. Ideally, you'd schedule a confirmatory PCR test at a doctor's office. If that also comes back positive, they definitely have COVID-19. If the PCR test comes back negative, however, then it's likely that the antigen tests were false positives and your kid doesn't have COVID-19.
"If the test is positive, follow the CDC guidance for quarantine and isolation," says Dr. Swanson. "Stay home. Stay hydrated. Monitor your symptoms. Stay away from un-immunized individuals, those at high-risk, and children as best you can for the full quarantine period."
Christine Coppa contributed to this report.