Here’s what you need to know about the new at-home COVID-19 tests

While many Americans (particularly those who live in states with new shelter-in-place policies) are doing their part to minimize the spread of COVID-19 through social distancing, one of the biggest obstacles to combatting the global pandemic remains the severe shortage of tests.

SARS-coronavirus-2 (aka the novel coronavirus that causes the disease COVID-19) is spread through close social contact, and can take up to two weeks to cause symptoms—meaning that people can be sick and spread the virus to others without knowing it. Accurate, reliable testing is crucial so that people who have the disease can get the proper care they need, and so that health and government officials know how serious the problem is and can plan prevention measures accordingly.

Unfortunately, many people who have been exposed to COVID-19 or have symptoms are having trouble getting access to tests. Part of the reason for the test shortage is that the first ones introduced by the the Centers for Disease Control and Prevention (CDC) in February were deemed too faulty to use. In the weeks since, academic, clinical, and other laboratories have struggled to make enough new tests to keep up with demand, and health-care providers haven’t been able to get reliable access to the tests, no thanks to shortages of other materials like swabs and pipettes needed to implement the tests.

In an effort to get more accurate tests to more people, private at-home testing companies have been working with the Food and Drug Administration (FDA) to develop and distribute their own. On Tuesday, the FDA announced its very first authorization of an at-home test, made by the company Labcorp. Three other private companies—Everlywell, Scanwell Health, and Nurx—recently announced the release of their at-home COVID-19 tests. But what are these at-home tests, and how effective are they? Here’s everything you need to know.

How the new at-home COVID-19 tests work

Currently, for someone to be tested for the novel coronavirus, a doctor has to determine whether the patient meets a specific set of criteria, which varies by state and county but is guided by the CDC’s recommendations. Criteria generally include experiencing symptoms and being in contact with someone with COVID-19 (or traveling from a high-risk country), or experiencing symptoms and having a negative rapid flu test.

Once a doctor decides that person should be tested, they undergo a standard COVID-19 test, which takes a swab to the back of a patient’s throat or nose, says Osmosis infectious disease physician Rishi Desai, MD, MPH. The swabs are sent to a lab, which tests the swab using reagents, aka substances used in chemical analysis to detect reactions. A positive reaction means the virus has been detected; a negative reaction means a person is (likely) in the clear. The process is supposed to take 24 to 48 hours after securing an appointment to take the test with a healthcare provider (although anecdotally people have reported days of delays in getting tested thanks to shortages).

Two of the new tests hitting the market from Everlywell ($135) and Nurx ($181) work very similarly to this standard test. For both brands’s tests, a person takes a digital questionnaire to determine if they should get tested, based on the above-mentioned guidelines from the CDC. This is to ensure that only people who truly need the test, and not just people who want to stockpile, get it.

If someone meets the criteria for testing, Christina Song, the director of communications at Everlywell, says a doctor affiliated with telemedicine service PWNHealth (which works with Everlywell) will prescribe the test. The test is then overnighted to the patient. “In the kit, there is a nasopharyngeal swab plus a tube where you can collect saliva and a sputum sample, which is a mixture of saliva and mucus. Once people collect their sample, we asked them to drop it into the biohazard safe materials that we provide into the shipping container,” Song says. (The kit also includes materials to disinfect the outside of the packaging.) The patient returns their sample with a pre-paid Fedex envelope and the test is analyzed at third-party, certified lab. Within 24 to 48 hours after being picked up, users will be able to see their results via Everlywell’s app. “The whole process from start to finish takes between three to five days,” she says. The turnaround time is technically comparable to COVID-19 testing available now, but given that it can be done without securing an in-person appointment with a doctor, it could save several days’ time.

If a test comes back positive, a board-certified doctor will follow up with the patient, via telemedicine, and walk them through the next steps, including the best ways to protect their health and others’ health. Nurx’s at-home test works similarly, with comparable steps in place if someone tests positive for COVID-19. One difference is that Nurx offers online consultations for users with negative results as well as positive ones, as they’ve found even those who don’t test positive still have many questions.

The at-home test by Scanwell Health, ($70), works differently, using technology that was developed and is being used in China to detect COVID-19. (It too includes a questionnaire component, and people who meet the criteria for testing are prescribed a test by a board-certified doctor.) Stephen Chen, founder and CEO of Scanwell Health, explains that this is an at-home blood test. It works by seeing whether or not a person has antibodies for the novel coronavirus in their system—which indicates that they’ve been exposed. The test is still pending approval via the FDA’s Emergency Use Authorization program (which facilitates the availability of treatments during health emergencies), but Chen estimates the test will be available to buy in about six to eight weeks.

“Basically, [the test] involves pricking your finger, [allowing] the blood to drop onto a cassette, adding a couple drops of the reagents to the cassette, and waiting 15 minutes to see if a reaction occurs,” Chen says. Users scan an image of the cassettes and upload it to the app. Then, it’s analyzed by medical professionals at Lemonaid, a telemedicine service. “The results are not showed to the patient using the app. Instead, a doctor is contacting them directly and giving them the results,” Chen says.

Positive results for all three tests will be reported to the CDC so they can keep track of the number of cases there are.

The implications of privatized testing for a health crisis

According to Dr. Desai, who is unaffiliated with any at-home testing company, there are pros and cons to private companies providing more testing options. One obvious benefit is providing more tests to more people. “There is a lot of medical and public health information we are going to get from [these at-home tests], including who needs to be quarantined,” he says. “It will also help a lot with anxiety reduction.” Plus, by not requiring an in-person doctor’s appointment, people who truly need tests should be able to get them faster.

But Dr. Desai says there’s a major downside with at-home testing: accuracy, particularly with nasal swabs. “Not every [throat or nasal] site has the virus, so a [nasal or throat swab] may miss it,” he says. There’s also a margin of error when it comes to the lab technique used to test the results the swab, which is called reverse transcription polymerase chain reaction, or RT-PCR. A study in the journal Radiology found that RT-PCR only detected the novel coronavirus in 59 percent of the 1014 patients with suspected cases studied; when they gave chest CT scans to those who received negative RT-PCR results, 75 percent had a positive chest CT findings—meaning that many of the negative RT-PCR results should have been positive. “It’s a good test, but it isn’t a great test,” says Dr. Desai.

This isn’t just a risk with the at-home tests; this is an ongoing issue with any COVID-19 testing that uses this method. But the risk for error is even higher at home. If someone collects the sample incorrectly at home, the virus won’t be detected at all, says Dr. Desai. (A representative for Everlywell says that the accuracy of their partner labs for the COVID-19 test “exceeds 95 percent.)

In terms of the blood test, Dr. Desai says he doesn’t know the accuracy (the CDC is currently working on its own blood test), but says in general this type of testing, which is also used to detect other viruses, autoimmune disorders, and some illnesses caused by bacteria, is “pretty fantastic.” “The accuracy for a [COVID-19 blood test] comes down to how sensitive it is and how early it can detect changes. There’s a big difference between detecting the virus on day one versus day 14,” he says. According to Jack Jeng, MD, Scanwell’s chief medical officer, data from the Chinese company that developed the test found the accuracy to be between 87 and 100 percent, depending on when a person takes the test. (It has the lowest accuracy if taken within the first two days of contracting the novel coronavirus.) But again, if someone takes their sample inaccurately at home, then it could lead to inaccurate results.

Another downside: the price. While testing for COVID-19 at a hospital or a doctor’s office will be free thanks to a new law passed by Congress, these testing kits cost up to $200 a pop, a price not everyone can afford to pay out of pocket. (Not exactly great in terms of increasing access to testing.) The COVID-19 at-home tests are not currently covered by insurance, although they will be covered by participating HSA and FSA carriers. (Song and Chen both say they are in contact with insurance providers in hopes of getting their companies’ tests covered to eliminate out-of-pocket costs.)

Song says her hope is to work with the federal government to make Everlywell tests free and more widely available; the price for the kit is just covering the testing and Everlywell is not making a profit. “The biggest obstacle is securing enough supplies,” she says. “The global shortage of nasopharyngeal swabs is the most significant barrier to ramping up our capacity to what it could be.” Similarly, Chen says Scanwell Health’s goal is to make their test more widely available and they do not anticipate making any profit off of these tests, either.

“Because these are private companies, there’s also the question of how else they are using the biological data they are collecting,” Dr. Desai says. To this end, Song and Chen both say their companies are bound to the Health Insurance Portability and Accountability Act and that no medical or personal data will be used for anything other than detecting and treating COVID-19.

Despite these real downsides, Dr. Desai says that he sees the value in these at-home tests, as well as others being developed, particularly for hospitals, health-care workers, and first responders. These are the people, Dr. Desai says, who have perhaps the most to gain for reliable, easy-to-access tests. “The way the coronavirus works is that if you get it once, you [likely] aren’t at risk for getting it again. So if a first responder tests positive for COVID-19, gets proper treatment, and then retests as negative, that’s fantastic.”

Given the difficulties that the federal government has had in managing this crisis, Dr. Desai says seeing private companies step in to serve a public need will become even more common in the future. “When you look at the last 20 years, we had SARS in 2002, we had MERS in 2012, and now we have COVID-19. So every six or seven years, this has happened with coronaviruses. It would be almost shocking if it didn’t happen again.”

This piece was originally published on March 20, 2020. It was updated on April 22, 2020.