News, Analysis, Trends, Management Innovations for
Clinical Laboratories and Pathology Groups

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News, Analysis, Trends, Management Innovations for
Clinical Laboratories and Pathology Groups

Hosted by Robert Michel
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Though clinical laboratory RT-PCR tests remain the ‘gold standard’ when diagnosing COVID-19, at-home antigen tests offer convenience and quick test results. But are they accurate?

Less than six months after the US Food and Drug Administration (FDA) issued the first ever emergency use authorization (EUA) for an over-the-counter SARS-CoV-2 diagnostic test to Ellume for its COVID-19 at-home antigen test, the number of do-it-yourself at-home tests available to consumers has grown large enough for Popular Science to publish a review of available consumer COVID-19 testing kits.

Clinical laboratory and pathologists generally acknowledge that RT-Polymerase Chain Reaction (RT-PCR) tests remain the preferred method for detecting COVID-19 disease. However, according to Popular Science, rapid at-home antigen tests that accurately identify people carrying larger loads of the virus are becoming important tools in the fight against spread of the coronavirus.

In “We Vetted Popular At-Home COVID-19 Tests. Here’s What We Learned: Everything you need to know about the growing number of at-home testing options for COVID,” Popular Science evaluated the ease-of-use and effectiveness of the following tests:

Many of the newest at-home tests not only have users collect their own swab or saliva samples, but some also provide results in less than an hour, which can be sent to the user’s smartphone. Conversely, home-based collection kits that are returned to clinical laboratories for testing can take 48 hours or longer for shipping and processing.

ellume-home-covid-test
The FDA’s emergency use authorization announcement (EUA) for Ellume’s $38.99 COVID-19 At Home Test (above) states the test “is a rapid, lateral flow antigen test, a type of test that runs a liquid sample along a surface with reactive molecules. The test detects fragments of proteins of the SARS-CoV-2 virus from a nasal swab sample from any individual two years of age or older.” Ellume’s self-collection test was the first such test to receive an FDA EUA for use without a physician’s order. (Photo copyright: Ellume).

Are At-Home COVID-19 Tests a Good Idea?

“The more we can do simple, regular, at-home testing, the less we need it,” Mara Aspinall, Professor, College of Health Solutions at Arizona State University, told Popular Science. “It’ll become a habit, as easy as brushing your teeth,” she added.

But in “Pathologists Urge Caution on At-Home COVID Test Kits,” MedPage Today, reporting on the College of American Pathologists (CAP) March 11 virtual media briefing, pointed out downsides to at-home COVID-19 tests.

Among the issues cited were the potential for inadequate samples and improper handling to cause inaccurate results, as well as uncertainty whether at-home antigen tests will pick up on COVID-19 variants.

At-home tests also are less likely to be covered by insurance, MedPage Today reported.

kalisha-hill-MD-head-shot
During the CAP virtual media briefing, pathologist Kalisha Hill, MD (above), Chief Medical Officer and Chair, Department of Pathology and Medical Director, Laboratory Services, at AMITA Health St. Mary’s Kankakee (Ill.), said, “The gold standard is still a laboratory-performed real-time PCR test and that is the most sensitive and most accurate that we do that is very specific for COVID-19.” Hill called at-home tests a “good screening tool,” but she noted, “You’re testing that moment, that day, and as soon as you leave your home or come in contact with someone else, you could potentially be COVID positive. It’s also important to recognize that when you’re collecting a sample yourself, you may not be able to obtain enough sample for an accurate result … It’s very important how it is collected and also the sensitivity and specificity of the test,” she added. (Photo copyright: AMITA Health/LinkedIn.)

How Do the Tests’ Accuracy Compare?

The Quest Direct and LabCorp Pixel tests—both of which are sent to company labs for PCR testing—scored highest on the two main statistical measures of performance sensitivity (positive percent agreement) and specificity (negative percent agreement). According to Popular Science, each of these tests’ sensitivities and specificities are close to 100%.

According to the websites of the other tests reviewed by Popular Science:

  • DxTerity test, which uses a saliva sample—97.2% sensitivity and a 92.5% specificity.
  • BinaxNOW test—84.6% sensitivity and 98.5% specificity.
  • Cue COVID-19 test—98.7% sensitivity and 97.6% specificity.
  • Lucira Check Its test—98% accuracy.
  • Ellume test—95% sensitivity and 97% specificity.

Rapid Antigen Tests Accurate and Easy to Use, says Popular Science

Popular Science found the tests generally easy to use and concluded they are a beneficial—if imperfect—tool in the fight against COVID-19.

“If you’re unvaccinated and symptomatic, they’re a great way to confirm a COVID-19 infection without risking a trip out of the house,” Popular Science stated in its article. “If you’re unvaccinated and have no symptoms, and just want to know whether you can safely attend a family dinner or soccer game, an at-home test remains an imperfect way of self-screening. Remember: If the test comes back negative, there’s still the chance the result is false, and you could accidentally expose others by being within six feet of them without a mask on.”

As the popularity of at-home COVID-19 tests increases, clinical laboratories that perform RT-PCR tests may want to keep a watchful eye on the demand for at-home rapid antigen testing, especially now that some tests are available without prescription.

Andrea Downing Peck

Related Information:

We Vetted Popular At-Home COVID-19 Tests. Here’s What We Learned

Coronavirus (COVID-19) Update: FDA Authorizes Antigen Test as First Over-the-Counter Fully At-Home Diagnostic Test for COVID-19

Pathologists Urge Caution On At-Home COVID Test Kits

The Rapidly Changing COVID-19 Testing Landscape: Vaccines, Variants, and Health Disparities

Cue COVID-19 Test for Home and Over-the-Counter (OTC) Use

DxTerity SARS-CoV-2 RT-PCR Test EUA Summary

Ellume’s COVID-19 Home Test Shows 96% Accuracy in Multi-Site US Clinical Study

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