These 30-Minute Nasal Swabs Are Like Pregnancy Tests—But for COVID

Here's how rapid antigen testing works—and how to get it.
February 9, 2021, 7:41pm
A negative rapid test for Covid-19 is at the vaccination centre.
A negative rapid test for Covid-19 is at the vaccination centre. (Photo by: Oliver Berg/picture-alliance/dpa/AP Images)

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You can now take a COVID test from the comfort of your home and receive results in the time it takes to watch an episode of TV. 

The FDA has authorized take-home rapid tests from three companies: Ellume, Abbott, and Lucira. The diagnostic tests are much more accessible than laboratory PCR (polymerase chain reaction) tests, which require professional equipment and can cost hundreds of dollars.

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The technology used in most of these at-home COVID tests is surprisingly similar to that of at-home pregnancy tests, and they’ll cost less than $50. With rapid-response tests, users simply apply a sample from a nasal swab to a small testing device, and within minutes a result will appear saying if the person testing is infected with COVID-19.

The take-home rapid tests are essentially pieces of paper covered with a substance meant to detect COVID-19 antigens, which coat the virus and induce an immune system response. So if someone is contagious with COVID-19 at that very moment, the test will likely come back positive. Once a person is infection-free, they won’t carry any antigens anymore. 

But someone exposed to COVID could also take the test too early—before they have enough viral load to induce a positive test. Still, rapid tests are meant to help people catch an infection on a day-to-day basis, not just when they feel sick, and medical professionals are hopeful they’ll shift the social paradigm of testing altogether.

“[If] you just get a PCR if you have symptoms or are exposed, then you will find out if you already have COVID. But that relies on usually waiting for the test and then another 2-3 days (sometimes longer) for the result, and very few people quarantine during that time,” wrote Dr. Ida Bergstrom, a Washington, D.C.-based travel precaution doctor, in an email to VICE News. 

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Several other companies are also currently seeking FDA approval for rapid diagnostic COVID-19 tests that would cost less than $10. Small private companies like E25Bio and even big players like 3M are teaming up with schools like Harvard and MIT to obtain approval to begin large-scale public distribution. 

PCR tests are 95-100 percent accurate all of the time, according to Nature. For both PCR and antigen tests, false positives should occur around zero percent of the time, according to an article by Harvard Medical School. False negatives, on the other hand, typically depend on how far into infection a patient is.

Rapid-response antigen tests can be 75 percent accurate if someone tests more than one week after coming down with the infection. Within the first week, that jumps to 84-95 percent accurate, according to Nature. But these rapid diagnostic tests aren’t meant to give a definitive answer. Instead, their ultimate goal—which only one of the three tests currently enables—is to let people monitor themselves throughout the pandemic, regardless of symptoms. 

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“I think the technology is good enough and doesn't need to be improved,” Dr. Bergstrom wrote. “If you try to make these tests ‘superior,’ you will lose the benefit. They will become too good and also be too expensive to be used in the manner they are intended.”

The U.S. isn’t the only country authorizing at-home rapid tests. South Korea, especially, is making them widely available to consumers, though there is some concern about their accuracy. Rapid diagnostic tests are also being used in developing countries where healthcare and access to labs capable of performing PCR tests are limited.

All three tests authorized by the FDA in the U.S.,  Ellume, Abbott, and Lucira, have slight variations but cost $50 or less. Here are the specifics: 

Ellume: 

For $30, anyone can buy Ellume’s test without a prescription whether they’re experiencing symptoms or not. The antigen test will be available at drugstores and pharmacies and is authorized for anyone age 2 or older.

The Department of Defense and Department of Health and Human Service have also invested $231.8 million into the production of this test, hoping to scale up production.  

Abbott:

At $25 plus shipping, Abbott’s antigen test, BinaxNOW, is cheaper but requires a prescription. To order one, a customer needs to make an appointment with an e-care provider who can then confirm the patient’s need for the test. If confirmed, a test can be either shipped to their house or picked up at a pharmacy. 

The company says those age 4 and older can take their test for accurate results. The test also has an online app where results will be sent to the user via mobile notification. 

Lucira:

Lucira’s tests are the most expensive at $50 because they don’t use antigen testing but rather technology similar to that of PCR tests. Results come back in 30 minutes. 

Still, a doctor must confirm a patient’s need for these tests, and they require a prescription for purchase. Those 14 and older can take this at home, but if a healthcare provider administers the test, those aged 13 are included too.