At-Home COVID-19 Antigen Test Kits: Where to Buy and What You Should Know

Molecular tests done in labs—the most well-known type being a PCR (polymerase chain reaction) test—are still considered the gold standard for confirming or ruling out a COVID-19 infection. But even though most at-home tests are not as sensitive as lab tests, they can quickly detect whether there is “a level of the virus that we have to be concerned that somebody could transmit [COVID-19] to someone else,” said Dr. Clare Rock, a clinical epidemiologist at Johns Hopkins University School of Medicine who runs a COVID-19 infection-control consultancy.

A negative at-home result, however, doesn’t necessarily mean that someone doesn’t have COVID-19. For instance, if you swab too soon after a potential exposure, you may test negative—even if you are carrying the virus. The CDC recommends that people who have come into close contact with someone who has COVID-19 should test at least five days after the encounter. With the Omicron variant, though, some experts have recommended that you test two to three days after exposure and, if negative, test again each day, or every other day, through day six.

Early data had suggested that some rapid antigen tests may fail to detect the Omicron variant during the early days of an infection, even when those people had high enough levels of the virus to pass it on to someone else (another reason to test again a day or so later). But a more recent and larger real-world study of three popular at-home rapid tests found that they were effective in catching the Omicron variant, particularly when viral loads were high. (Note that the authors of this study, which has not yet been peer-reviewed, have received consulting and research grants, as well as non-financial assistance, from Bristol-Myers Squibb, Pfizer, LG, and Apple, among other companies.) Another study also found that Abbott BinaxNow tests could detect multiple variants of COVID-19, including Omicron.

Although PCR tests are known to be so sensitive that they can detect a weeks-old COVID-19 infection (even after the person is no longer infectious), that’s not the case for rapid antigen at-home tests. If you test positive with an antigen at-home test, even after staying home for the recommended five days, you’re quite possibly still infectious. “If you’re positive, you’re positive,” said Dr. Wilbur Lam, a professor of pediatrics and bioengineering at Emory and the Georgia Institute of Technology and a clinical pediatric hematologist at Children’s Healthcare of Atlanta.

Abbott BinaxNow COVID-19 Antigen Self Test

Sensitivity: 84.6% (PDF) within seven days of symptom onset

Specificity: 98.5% (PDF) within seven days of symptom onset

Tests included: two

App needed: no

Omicron variant detected: yes

Cost: about $20 at the time of publication

Availability: Amazon, CVS, Walgreens

Note: To submit verified proof of a negative result, such as for travel, you need to purchase a BinaxNow test that comes with a virtual visit with eMed.

Access Bio CareStart COVID-19 Antigen Home Test

Sensitivity: 87% (PDF)

Specificity: 98% (PDF)

Tests included: two

App needed: no

Omicron variant detected: yes (PDF)

Cost: about $20 at the time of publication

Availability: Target

Acon Flowflex COVID-19 Antigen Home Test

The FDA is aware that counterfeit versions of the FDA-authorized Flowflex COVID-19 Antigen Home Tests are being illegally imported and distributed in the United States through unauthorized distributors and resellers who have no connection to ACON Laboratories, Inc.,” the agency said in a statement. Read on for how to check for signs of counterfeit tests and what to do if you suspect you have a fake test. In March 2022, the FDA issued a warning not to use unauthorized “ACON Biotech Flowflex SARS-CoV-2 Antigen Rapid Test (Self-Testing)” kits in dark blue packaging.

Sensitivity: 93% (PDF)

Specificity: 100% (PDF)

Tests included: one

App needed: no

Omicron variant detected: yes

Cost: about $10 at the time of publication

Availability: CVS, Target, Walgreens, WellBefore

BD Veritor At-Home COVID-19 Test (app required)

Sensitivity: 84.6% (PDF)

Specificity: 99.8% (PDF)

Tests included: two

App needed: yes (iOS and Android)

Omicron variant detected: yes

Cost: about $30 at the time of publication

Availability: Amazon

Note: Unlike with other tests, with this one two lines mean that you are negative for COVID-19; three lines mean you are positive.

Celltrion DiaTrust COVID-19 Antigen Home Test

Sensitivity: 86.7%

Specificity: 99.8%

Tests included: two

App needed: no

Omicron variant detected: unclear

Cost: $25 at the time of publication

Availability: Amazon

Note: The FDA issued a warning not to use any Celltrion tests with green and white packaging.

Clinitest Rapid COVID-19 Ag Self-Test (Siemens Healthineers)

Sensitivity: 86.5%

Specificity: 99.3%

Tests included: five

App needed: no

Omicron variant detected: yes

Cost: $50

Availability: Amazon

Note: Sold only in a pack of five.

Ellume COVID-19 Home Test (app required)

Ellume recalled certain lots of its COVID-19 Home Test because they may provide false-positive results. To determine whether an Ellume test you have is affected by the recall, visit the company’s website.

Sensitivity: 95% (PDF)

Specificity: 97% (PDF)

Tests included: one

App needed: yes (iOS and Android)

Omicron variant detected: yes

Cost: about $40 at the time of publication

Availability: CVS, Target, Walmart

iHealth COVID-19 Antigen Rapid Test

The FDA has identified counterfeit versions of this test being sold in the US. “The FDA is aware that counterfeit versions of the FDA-authorized iHealth COVID-19 Antigen Home Tests are being illegally imported and distributed in the United States through unauthorized distributors and resellers who have no connection to iHealth Labs, Inc.,” the agency said in a statement. Read on for how to check for signs of counterfeit tests and what to do if you suspect you have a fake test.

Sensitivity: 94.3% (PDF)

Specificity: 98.1% (PDF)

Tests included: two

App needed: no

Omicron variant detected: yes

Cost: about $25 at the time of publication

Availability: Amazon, iHealth

Intrivo On/Go COVID-19 Antigen Self-Test (made by Access Bio)

Sensitivity: 87% (PDF)

Specificity: 98% (PDF)

Tests included: two

App needed: yes (iOS and Android)

Omicron variant detected: yes (PDF)

Cost: about $25 at the time of publication

Availability: Amazon, On/Go, Walgreens

Note: Intrivo On/Go packages and distributes the CareStart COVID-19 Antigen Home Test through a partnership with Access Bio.

On/Go One COVID Test (made by Acon Laboratories)

Sensitivity: 93% (PDF)

Specificity: 100% (PDF)

Tests included: one

App needed: yes (iOS and Android)

Omicron variant detected: yes

Cost: $9

Availability: Amazon, On/Go

Note: On/Go packages and distributes the Flowflex COVID-19 Antigen Home Test through a partnership with Acon Laboratories.

Orasure InteliSwab COVID-19 Rapid Test

Sensitivity: 84% (PDF)

Specificity: 98% (PDF)

Tests included: two

App needed: no

Omicron variant detected: yes

Cost: about $25 at the time of publication

Availability: Walgreens, Walmart

Note: InteliSwab’s results are available in 30 minutes, rather than 10 to 15 minutes as with other tests.

Quidel QuickVue At-Home OTC COVID-19 Test

Sensitivity: 84.8% (PDF)

Specificity: 99.1% (PDF)

Tests included: two

App needed: no

Omicron variant detected: yes

Cost: about $25 at the time of publication

Availability: Amazon, CVS, Walgreens, WellBefore

The FDA has granted emergency use authorization (EUA) to a growing number of rapid at-home COVID-19 tests that are available to shoppers, without a prescription, in pharmacies and online. Most at-home kits come with two tests and cost between $20 and $40—though a few, such as Acon’s Flowflex COVID-19 Antigen Home Test, come with only one test and cost about $10.

The accuracy of an at-home antigen test depends in part on test sensitivity (the test’s reported ability to detect a true positive), test specificity (its reported ability to detect a true negative), sample integrity (whether a swab contains enough sample or the swab solution is contaminated by, say, another pathogen), whether someone follows the manufacturer’s instructions exactly, the time since a person’s last known or suspected exposure and/or their onset of symptoms, and the person’s viral load at the time of testing. In general, these tests all have about the same ability to detect the virus, and you should feel comfortable using any of them to check whether you’ve contracted COVID-19, said Dr. Michael Mina, a former Harvard epidemiologist who is now the chief science officer for eMed, which sells a version of BinaxNow for certified results (such as for travel). Of note, in a recent and not yet peer-reviewed study of 700 people in San Francisco, the BinaxNow at-home tests were able to detect most people who were infected with the Omicron variant and were carrying high levels of the virus, The New York Times reported.

For a test to be considered for emergency use authorization, test makers must submit to the FDA clinical data demonstrating test sensitivity and specificity. Note that these sensitivity and specificity percentages are a snapshot in time, with a limited sample—all FDA-authorized tests have proved they can detect an infection. (Some independent studies have shown much lower sensitivity and specificity for some antigen tests, particularly when they’re used on asymptomatic individuals.) “Most of these tests do work, but there is no such thing as a perfect test that works 100 percent of the time,” said Lam, who is part of a team testing new rapid antigen tests, and verifying that they can detect COVID-19, on behalf of the National Institutes of Health.

As new coronavirus variants—including Omicron and its BA.2 form—have emerged, manufacturers have self-reported whether their tests can detect them. The FDA is also monitoring the tests’ effectiveness in detecting the Omicron variant; thus far, the data has been mixed. The FDA has said that although the tests can detect the Omicron variant, they may not be as sensitive to it, which means you may get a false negative at first.

The tests are authorized for use on people as young as 2 years old, provided that any child’s sample is obtained and processed by an adult. (The results of a March 2022 study, which has not yet been peer-reviewed, suggest that kids as young as 4 may be able to swab and collect the sample on their own, provided they watch an instructional video.) The instructions that accompany all of the tests listed below also include a disclaimer indicating that negative results may require additional testing for confirmation. For each of them, there’s a small (and lesser) chance of false-positive results, too.

The following tests are FDA-authorized and available for purchase.

Note: Availability of these tests fluctuates frequently.

The FDA has also authorized three molecular tests for emergency use at home without a prescription or the need to send a sample to a lab for testing. The results take longer, from about 30 minutes to an hour, but are supposed to provide “PCR-quality results” and have a better likelihood of detecting COVID-19 early on. These tests are much more expensive because they include a machine that magnifies the sample and reads the results.

Cue COVID-19 Test & Cue Reader (app required)

Sensitivity: 97.4%

Specificity: 99.1%

Tests included: three

App needed: yes (iOS and Android)

Omicron variant detected: yes

Cost: $445 at the time of publication for a Cue Reader and three tests

Availability: Cue Health

Note: The Cue Reader costs $250 on its own. Subsequent tests are available for purchase in packs (a three-pack costs $195). You can also purchase a Cue+ membership for test certification (such as for travel or returning to work) and virtual care.

Detect (app required)

Sensitivity: 90.9% (PDF)

Specificity: 97.5 (PDF)

Tests included: one

App needed: yes (iOS and Android)

Omicron variant detected: yes

Cost: $75 at the time of publication for a starter kit

Availability: Detect

Note: Subsequent tests cost $50 each. The hub—the machine that reads the results—costs $40 on its own.

Lucira Check It COVID-19 Test (smartphone required)

Sensitivity: 94.1% (PDF)

Specificity: 98% (PDF)

Tests included: one

App needed: no, but a smartphone is required for a verified result (texting, data, camera, and mobile browser needed)

Omicron variant detected: yes

Cost: $75 at the time of publication for a single-use kit

Availability: Amazon, Lucira

At-home antigen tests require a relatively noninvasive nasal swab.

Each test comes with specific instructions, which essentially require you to collect a sample with a swab, dip the swab into a solution, transfer some of the solution into a small reservoir, and wait for the result.

For some tests, such as the Abbott BinaxNow and Quidel QuickVue tests, you can read the results after 15 minutes or so, much as you would a home pregnancy test: Two lines indicate a positive result, and one line (the control) indicates a negative. A very faint second line can still indicate a positive result. (Check your results during the designated window of time, not earlier or later.)

Other tests, such as the BD Veritor At-Home COVID-19 Test, provide results in 15 minutes with the help of a smartphone app. These apps walk you through the steps of collecting your sample and interpreting the results. With these tests, the user’s date of birth, state and zip code of residence, test result, test result date, and possibly other information may be shared with public health authorities as required by law (per Ellume’s privacy policy, BD’s privacy policy, and Intrivo’s privacy policy).

With the Omicron variant, some experts initially suggested that swabbing both the nose and throat may allow you to detect the virus earlier. (Some tests available in the UK and other countries collect samples from both the nose and throat.) But others have since discouraged that practice. The FDA (which has authorized at-home tests for use with a mid-nasal swab only) tweeted that “those swabs are for your nose and not your throat.” A recent study (which has not been peer-reviewed) also found that a nasal swab detected the virus better than a throat swab. “We found that swabbing the throat was inferior to swabbing the inside of the nose, when we compared swabbing the same person at the same time,” said Joe DeRisi, president of the Chan Zuckerberg Biohub, a research institute in San Francisco. “Swabbing the throat missed about half of the infections caught by swabbing the inside of the nose.”

In March 2022, the FDA issued additional safety precautions for using at-home COVID-19 tests, advising people to use and store home tests per manufacturers’ instructions (which all specify room-temperature use and storage) and to keep them out of reach of children and pets. (The agency had received reports of children accidentally ingesting the liquid solution or pieces of the test.) Having received reports of people mistaking the small vials of test-kit solution for eye drops, the FDA also cautioned that the solution is not meant to touch any part of the body. If you’ve had a problem with any at-home test, you can report it to the FDA.

Test makers are also still developing ways to make these tests accessible for people with certain disabilities. The New York Times recently reported on the challenges that people who are blind or have limited vision can face when administering home tests. These tests require precise steps—with BinaxNow, for instance, you must squeeze six drops of liquid into a small hole on the test card—and require visually interpreting the results. Apps such as Be My Eyes and Aira can provide some visual assistance.

Based on initial studies, the FDA authorized home Covid tests to have expiration dates of about four to six months. Portions of the tests can degrade over time, which can give you an inaccurate result, though scientists have yet to determine an exact length of time after which certain kit components become unreliable. Generally speaking, the agency advises against using expired test kits. Now that there has been more time for experts to evaluate the tests, several manufacturers, such as Abbott and On/Go, have received FDA authorization to extend their expiration dates (assuming that the tests have been stored at specific temperatures). If the expiration date on your test has come and gone, consult this FDA list—which denotes extended expiration dates for certain tests—and the manufacturer’s website before tossing it.

In late April and early May 2022, the FDA warned consumers about the distribution and sale of counterfeit home Covid tests with “Flowflex” and “iHealth” branding. “These counterfeit tests should not be used or distributed,” the FDA said, noting that “current evidence suggests the counterfeit tests are not performing as well as the authorized tests,” meaning the tests can’t be relied on to accurately determine whether a person is positive or negative for COVID-19. Legitimate Acon Flowflex and iHealth tests authorized for emergency use are still safe to use, the agency said.

Signs you may have a fake test include poor print quality on the packaging and inserts; missing lot numbers, expiration dates, and/or QR codes on the outside of the box; materials that accompany the test don’t look exactly like the ones that come with FDA-authorized tests (see comparison photos here). The agency acknowledges that it can be hard to tell fake tests from legitimate ones: “The packaging and components of the fraudulent tests very closely resemble real, FDA-authorized” at-home Covid tests from Acon Flowflex and iHealth.

What to do if you suspect you have a fake test

Do not use a home Covid test you suspect may be counterfeit, the FDA says. The agency is advising consumers to contact the store or distributor where they bought the suspected fake, as well as the manufacturer of the authorized test. According to the FDA, authorized test manufacturers can provide instructions for returning or disposing of fake tests. (Acon Laboratories says it is “unable to receive returns” of counterfeit Flowflex tests, and suggests that consumers destroy them.)

Testing requirements vary by destination. Of the tests available to the public, Abbott’s BinaxNow may be accepted for travel when the sample is collected and the results are verified through a virtual visit. (Note that you must purchase a specific test that comes with a virtual visit through eMed. The standard BinaxNow test sold at Walmart and other major retailers is not accepted.) Cue, Detect, and Lucira tests may also be accepted for travel in certain circumstances.

As is true for all COVID-19 diagnostics, including PCR tests, the timing of the sample collection in relation to the last known or suspected exposure and/or symptom onset is the biggest factor that can affect accuracy. This is why Abbott’s BinaxNow and Quidel’s QuickVue test kits, for example, come with two tests, intended for use between two and three days apart.

“Serial testing boosts sensitivity,” said Christopher Brooke, an infectious-disease expert at the University of Illinois at Urbana-Champaign. “The odds that you’re going to test negative twice when you’re infected are much lower than the odds that you’re going to test negative once.”

An infected person’s viral load changes over time. “The sensitivity of a test really depends on when you use it,” said Daniel Larremore, assistant professor of computer science at the University of Colorado Boulder, who has modeled the effects of repeated population screening of asymptomatic people with molecular and antigen tests.

“When you reach a high enough viral load, antigens are going to be at a high enough concentration to be detected,” Larremore said. Testing yourself the day after attending a party with someone who didn’t know they had COVID-19 at the time is unlikely to be useful. “Twenty-four hours after exposure, no test is going to be positive,” Larremore said. On the other hand, if you wait too long to test, you may miss peak antigen concentration, meaning you should see a fainter positive line if the test detects COVID-19 antigens in your sample.

The Omicron variant has also shifted the timetable for detecting the virus: People are showing symptoms earlier (though the symptoms may be slightly different), alerting them that they need to test. But even though people may already be symptomatic and infectious, they may not have enough of the virus in their nose to be detected by a rapid test.

If you already have COVID-19–like symptoms, you should isolate. If you have a limited supply of at-home tests, you may want to wait a day before testing, for a better chance of catching a positive result. “Don’t waste a rapid test on the first day of symptoms,” Mina said. If your result is negative, you should test again a day or two later.

If you’re taking a test before attending a gathering or seeing someone vulnerable, the best time to test is just before you walk through the door—don’t rely on a test from the day before because your results can quickly change.

If you’ve attended a large indoor gathering, traveled, or received a notice of exposure, experts recommend testing two to three days after the exposure or event. And if your test is negative, you should test again—ideally the next day or every other day until day six (the day of exposure counts as day zero).

Of course, if you test positive, you should take precautions right away.

And if you still test positive with a rapid antigen test after the recommended five-day quarantine, experts say you should trust the test result and continue to take precautions.

Tracy Vence contributed reporting.

This article was edited by Courtney Schley and Kalee Thompson.