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Popular Science Review Finds Seven At-Home COVID-19 Antigen Tests ‘Easy to Use’ and ‘An Important Tool to Slow Spread of the Coronavirus’

Jun 2, 2021 | Compliance, Legal, and Malpractice, Instruments & Equipment, Laboratory News, Laboratory Operations, Laboratory Pathology, Management & Operations

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:

Ellume COVID-19 Home Test: A nasal swab test that delivers results in 15 minutes. Sold online and at CVS Pharmacy for $38.99.
DxTerity SARS-CoV-2: This saliva-based collection kit is available on Amazon and at Walmart for $110. Specimens must be sent via FedEx on the same day as collection. Results are available within 24 to 72 hours of the sample being received by the PCR testing lab.
Cue COVID-19 Test for Home and Over the Counter Use: This is the first molecular diagnostic test available for at-home use without a prescription to receive FDA emergency use authorization. The nasal swab test provides results in about 20 minutes on a user’s mobile device. The test currently is only being distributed by the Department of Defense (DoD) and Department of Health and Human Services (HHS). Retail pricing has not yet been released.
Lucira Check It COVID-19 Test Kit: Billed as offering “PCR quality molecular accuracy,” this nasal swab test costs $55 and provides results in 30 minutes or less.
Abbott BinaxNOW Antigen Self-Test. Results within 15 minutes and available for $23.99 at major pharmacies. Each box includes two nasal swab tests, with the second test taken within 36 hours of the first.
Pixel COVID-19 At-Home Collection Kit: This nasal-swab-based mail-in collection kit is available online for $119. Results delivered within 24 to 48 hours of the sample being received by Labcorp.
Quest Direct COVID-19 Active Infection: This $119 nasal swab kit requires an additional $9.30 PNW Health physician fee. Results are expected within 24 to 48 hours of the sample being received by Quest Diagnostics.

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:

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

FDA Authorizes First At-Home COVID-19 Antigen Tests, but Roadblocks Remain for “Fast-and-Frequent” Antigen Testing

Dec 23, 2020 | Compliance, Legal, and Malpractice, Instruments & Equipment, Laboratory Management and Operations, Laboratory News, Laboratory Operations, Laboratory Pathology, Management & Operations

Developers of medical laboratory tests had high hopes that cheap saliva-based tests would compete with at-home OTC tests that use nasal swabs, but skepticism among scientists continues

Reverse-transcription polymerase chain reaction (RT-PCR) technology has become the standard for clinical laboratory diagnostic testing used to detect the presence of the SARS-CoV-2 coronavirus. However, to enable more widespread testing, some public health experts have called for deployment of cheap, rapid, saliva-based antigen tests that could be self-administered by consumers in their homes.

Despite the technology’s lower sensitivity compared with RT-PCR testing, the idea of “fast-and-frequent” universal antigen testing has gained support as a possible game-changer against the outbreak, the New York Times reported.

The FDA recently took a step in this direction with its first emergency use authorization for the Ellume COVID-19 at-home antigen test. But other developments suggest that these tests may fall short of the lofty vision initially outlined by the experts.

Ellume’s COVID-19 Home Test (above) received emergency use authorization from the FDA on December 15. In a press release, Ellume claimed its rapid-antigen test, “demonstrated a sensitivity of 96% and specificity of 100%, and in asymptomatic individuals, the test demonstrated a sensitivity of 91% and specificity of 96%. This level of accuracy across both symptomatic and asymptomatic individuals is crucial in mitigating the spread of an infectious disease like COVID-19.” (Photo copyright: Ellume.)

The Promise of Rapid Antigen COVID-19 Tests

In a column he wrote for Time in July, Ashish K. Jha, MD, MPH, a practicing General Internist and Dean of the Brown University School of Public Health, described the promise of rapid antigen tests. “Imagine spitting on a special strip of paper every morning and being told two minutes later whether you were positive for COVID-19,” he wrote. “If everyone in the United States did this daily, we would dramatically drop our transmission rates and bring the pandemic under control.”

Another advocate for this approach is Michael Mina, MD, PhD, an assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health and a core member of the School’s Center for Communicable Disease Dynamics (CCDD). In a commentary for Time in November he wrote, “Widespread and frequent rapid antigen testing (public health screening to suppress outbreaks) is the best possible tool we have at our disposal today—and we are not using it.”

However, one major issue with antigen testing is sensitivity. “Antigen tests require higher levels of virus than qPCR [quantitative polymerase chain reaction] to return a positive result,” Jha wrote in Time. However, he contends, “the frequency of testing and the speed of results” counter concerns about accuracy.

Even with lower sensitivity, Jha wrote, the quicker test results from antigen tests “would identify viral loads during the most infectious period, meaning those cases we care most about identifying—at the peak period of infectiousness—are less likely to be missed.”

As the FDA explains, RT-PCR molecular tests “detect the virus’ genetic material,” whereas, according to an article published in Nature, titled, “Fast Coronavirus Tests: What They Can and Can’t Do,” antigen tests can “detect specific proteins … on the surface of the virus, and can identify people who are at the peak of infection, when virus levels in the body are likely to be high.”

At-Home Antigen Tests Receive EUAs

The new antigen test developed by Ellume is “the first over-the-counter (OTC) fully at-home diagnostic test for COVID-19,” the FDA said in a press release. The user self-administers a nasal swab and places it in an analyzer connected to a smartphone app. It can deliver results in 20 minutes. The company states that its test has overall sensitivity of 95% and specificity of 97% based on a clinical study of 198 subjects in a simulated home setting.

Jeffrey Shuren, MD, JD, Director of FDA’s Center for Devices and Radiological Health, said in the FDA press release, “This test, like other antigen tests, is less sensitive and less specific than typical molecular tests run in a lab. However, the fact that it can be used completely at home and return results quickly means that it can play an important role in response to the pandemic.”

Ellume expects to deliver about 20 million tests to the US by the end of June 2021. Multiple outlets reported that the test will cost about $30, AP News reported.

Meanwhile, the FDA also authorized at-home use of Abbott’s BinaxNOW rapid antigen test, which was previously authorized for use in point-of-care settings. This test, which requires a prescription, will sell for $25.

In a series of tweets, Harvard’s Mina applauded both moves, but he wrote that they [antigen tests] still fall short of his vision for fast and frequent testing. He described Abbott’s BinaxNOW as “the type of rapid test I have been calling for,” but said he’d like to see tests priced far less and available without a prescription.

Diminishing Prospects for Saliva-based Antigen Tests?

All rapid antigen tests authorized by the FDA so far require nasopharyngeal and/or nasal swab specimens, and it appears that it may be a long time, if ever, before saliva-based antigen tests are available. The New York Times (NYT) reported in October that two companies working on antigen tests—E25Bio and OraSure (NASDAQ:OSUR)—have dropped plans to enable use of saliva.

E25Bio founder Bobby Brooke Herrera, PhD with E25Bio co-founder and Chief Technology Officer Irene Bosch — “If I was placing a bet—which I am, because I’m leading an antigen-based testing company—I would say it’s going to be very difficult for antigen-based testing to work on saliva samples,” E25Bio founder **Bobby Brooke Herrera, PhD** **(above with E25Bio co-founder and Chief Technology Officer** **Irene Bosch) told the *NYT*. (Photo copyright:** **WCVB-TV**.)

One advantage of a saliva-based test is that it would be easier to self-administer. “But as they continued to tinker with their tests, researchers at both E25Bio and OraSure found saliva’s performance to be more lackluster than anticipated, and were forced to pivot,” the New York Times reported. Instead, both companies will seek authorization for use of their tests with nasal swabs.

HHS Contract for Antigen Tests Brings High Rates of False Positives

A recent investigative story in ProPublica, titled, “Rapid Testing Is Less Accurate than the Government Wants to Admit,” raised additional questions about rapid antigen testing. In August, the US Department of Health and Human Services announced it had awarded a $760 million contract for 150 million Abbott BinaxNOW tests to be distributed to schools and nursing homes. But later, according to ProPublica, healthcare workers in Nevada and Vermont reported high rates of false positives.

“With the benefit of hindsight, experts said the Trump administration should have released antigen tests primarily to communities with outbreaks instead of expecting them to work just as well in large groups of asymptomatic people,” ProPublica reported. “Understanding they can produce false results; the government could have ensured that clinics had enough for repeat testing to reduce false negatives and access to more precise PCR tests to weed out false positives.”

A few weeks after the reports from Nevada and Vermont, the FDA issued a letter advising clinical laboratories and healthcare providers about the possibility of false positives, along with steps they could take to improve accuracy.

Though some experts remain hopeful about “fast-and-frequent” testing, others are skeptical and say more research is needed to assess the value of this approach. “We are open to thinking outside the box and coming up with new ways to handle this pandemic,” Esther Babady PhD, D(ABMM) of Memorial Sloan Kettering Cancer Center, told the New York Times. However, she added, “the data for that is what’s missing.”

Nevertheless, were at-home rapid saliva-based antigen tests to become a common choice for healthcare consumers, clinical laboratories that perform RT-PCR testing for COVID-19 could see a marked decrease in orders. Thus, regardless of the current state of antigen testing, its development is worth watching.

—Stephen Beale

Related Information:

How We Can Stop the Spread of COVID-19 by Christmas

Over-the-Counter Home Test for COVID-19 Gets US Green Light

‘A Major Breakthrough’: FDA Authorizes Nation’s First At-Home, Over-the-Counter COVID-19 Test

FDA Authorizes First Rapid, Over-the-Counter Home Coronavirus Test

Rapid Testing Is Less Accurate than the Government Wants to Admit

Daily Coronavirus Testing at Home? Many Experts Are Skeptical

Home Tests Could Help in the Fight Against the Coronavirus. So Where Are They?

Screening to Prevent SARS-CoV-2 Outbreaks: Saliva-Based Antigen Testing Is Better than the PCR Swab

America Needs to Radically Rethink Our COVID-19 Testing Approach

Test Sensitivity Is Secondary to Frequency and Turnaround Time for COVID-19 Surveillance