By Paul Nicolaus
May 6, 2021 | Quidel and Abbott have introduced at-home COVID-19 antigen tests that do not require a prescription and deliver results in just minutes.
The tests, which received Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA) in late March, are opening up a new level of testing availability. They are also completely independent of doctor oversight or reporting of results.
Consumers have previously been able to purchase at-home COVID-19 test kits, but the nasal or saliva samples had to be mailed off to a lab for processing. Quidel’s QuickVue At-Home OTC COVID-19 Test and Abbott’s BinaxNOW COVID-19 Antigen Self Test, on the other hand, deliver results within 15 minutes.
This turnaround time is similar to the Ellume COVID-19 Home Test, which has been available for in-home use since Dec. 2020. One notable difference is that Ellume’s at-home option requires users to download an app to take the test, and the results are automatically reported to public health authorities.
“The important point about these recently approved products is increasing access to testing,” Michael A. Pentella, professor of epidemiology and director of the State Hygienic Laboratory at the University of Iowa, explained. “All of these are useful so that people who may be infected can get a quick result without leaving home.”
The value is the speed of the result, he told Diagnostics World, which arrives in minutes rather than hours or days. Whereas both symptomatic and asymptomatic people can be tested using these products, they are thought to perform best when used with symptomatic individuals.
Detecting cases is essential for stopping transmission, Pentella added, and these tests are one tool that can make detection easier and help end the COVID-19 pandemic.
Others see this new development differently. “COVID antigen testing is of limited value,” according to Alan Wells, medical director of the UPMC Clinical Laboratories and professor of pathology at the University of Pittsburgh School of Medicine. The tests have sensitivity limitations, he told Diagnostics World, and are open to misinterpretation.
He believes people should instead use “increasingly available and responsive testing sites” for “more valid and informative testing.” In many cases, this may involve similar antigen testing, but it also includes the interpretation of results.
Overview of QuickVue and BinaxNOW
For the use of Quidel’s QuickVue test, an individual 14 years or older self-collects a sample using a nasal swab, or an adult collects the sample from a child age two or older. That sample is put into a pre-filled tube, and after stirring, it is left for at least a minute before being removed. The test strip is then put into the tube, and after 10 minutes, the results can be read using the presence or absence of colored lines similar to a home pregnancy test.
The test is meant to be used twice over two or three days, with 24 to 36 hours between tests, according to Quidel. Its positive results agree with PCR testing 83.5% of the time and with negative results 99.2% of the time.
Initially, Quidel will progressively roll out the test as its new manufacturing facilities come online and the company scales production. According to a company spokesperson, the plan is to reach 50 million tests monthly before the end of the year.
Quidel says it is committed to making its QuickVue At-Home OTC COVID-19 Test affordable for consumers but noted that retailers ultimately determine the price charged at the register. Quidel has not yet determined its wholesale pricing for use at businesses and schools but indicated the cost would be “significantly lower than retail.”
Abbott’s BinaxNOW COVID-19 Self Test enables people age 15 and older to self-collect or adults to help children as young as two years old. The test is intended to be used twice over three days with at least 36 hours between testing and is sold two to a kit for an MSRP of $23.99.
On Apr. 19, Abbott announced it had begun shipping to retailers across the country, noting the test would initially be available at CVS Pharmacy, Walgreens, and Walmart with broader nationwide availability to follow via other major food, drug, and retail stores.
The company plans to manufacture tens of millions of these tests every month and “can further scale capacity based on demand.” Abbott indicated it would work with retailers to prioritize distribution in regions where the virus surges as additional supply becomes available online.
The person performing the test adds several drops of extraction reagent from a dropper bottle to the swab well. The nasal swab sample is inserted into the test card and rotated before the card is closed, which brings the sample into contact with the test strip. Results are available within 15 minutes based on the presence or absence of colored lines.
While there is no testing oversight involved, the FDA’s EUA document stated that “the user should share their results with their healthcare provider.”
Abbott introduced its BinaxNOW professional test back in August 2020 and scaled up production to 50 million tests per month, which have been used by K-12 schools, colleges and universities, nursing homes, and workplaces. The BinaxNOW Self Test relies upon this same technology but enables people to test themselves without a prescription.
The BinaxNOW antigen test has shown an overall performance of 84.6% positive agreement and 98.5% negative agreement when used with people who are seven days or less post-symptom onset, according to Abbott. An evaluation of the test in a community setting found an overall sensitivity of 89% among samples from roughly 3,300 participants. The study, published in Clinical Infection Diseases (doi.org/10.1093/cid/ciaa1890), also revealed an overall specificity of 99.9%.
However, some experts have cautioned that antigen tests can miss the virus if a person is early in the infection or does not display symptoms. A CDC study published in January 2021, for instance, revealed that Abbott’s BinaxNOW antigen test identified less than 36% of infections in asymptomatic individuals.
Advantages and Drawbacks of At-Home Antigen Testing
“The latest round of at-home antigen tests offers greater accessibility, quicker results, and lower costs compared to early tests that required a nasal sample to be taken at home, then mailed back to a complex lab or medical provider,” explained Barry Abraham, president of Empowered Diagnostics, a company that has developed at-home COVID-19 antigen tests.
This type of testing eliminates the need to wait in line or set up an appointment with a medical provider. “Access to highly sensitive, affordable rapid tests is essential to safely returning to our workplaces, schools, and communities,” he told Diagnostics World. “At-home rapid tests, if highly sensitive, can play a huge role in bringing our communities back together.”
The highest-performing at-home antigen tests can potentially catch cases before individuals become contagious, and “that’s huge for preventing outbreaks,” Abraham said. People will have the option of purchasing tests to use before and after potentially risky events, such as weddings. Although access is important, he added, so is the quality of the test—especially sensitivity.
If everyone has access to an at-home test but its sensitivity is only 60%, for example, “that’s about as useful as flipping a coin,” he explained. A low-sensitivity test is more likely to produce a false-negative result, which “creates a false confidence delay.” In other words, test users don’t think they have COVID and may delay taking another test even if they feel sick, all the while infecting those around them.
Another potential downside of at-home testing is that people may not follow instructions accurately or read their results correctly, he added.
Geoffrey Trenkle, chief medical officer of Total Testing Solutions, a company focused on bringing a wide range of COVID-19 tests to individuals, families, and businesses in the Los Angeles area also pointed to the potential for false-negative results as a notable disadvantage to this type of testing.
Take the scenario of someone who is carrying the virus but does not have symptoms. Suppose the test incorrectly returns a negative result. That person may feel comfortable going to a party without a mask, skipping social distancing, or even hugging their friends—all of which could lead to spread that may not have otherwise occurred.
Even so, Trenkle believes more testing is often better than none at all.
And in addition to availability, he highlighted cost as a critical advantage to at-home self-testing. Without the upcharge for staffing and monitoring, companies can sell directly to consumers and drive the cost down in the process, he explained.
This allows rapid testing to become available to more people and could help grow the amount of testing being conducted overall. “When people feel sick, they may be more prone to get a test if they can know the results immediately,” Trenkle said. It becomes possible to keep a handful of tests at home and use them before going out with friends or visiting family.
Other experts, meanwhile, have called at-home testing a luxury that much of the population simply cannot afford.
Testing Frequency and Public Health Implications
“Ideally, daily testing would be best to detect asymptomatic individuals who may be unknowingly infectious,” Pentella said. Still, it is up to the individual to determine testing frequency based on their unique situation.
Someone with a known exposure or a job that places them at risk of exposure might want to test, for example. If someone needs to protect others, they may want to test as well. Those who know they are infected are less likely to infect others, he added.
Trenkle also noted the benefits of high-frequency testing. “In a perfect world, we are all testing at least three times per week to screen for the virus,” he said. And he believes this level of testing is, indeed, scalable. “The hard part isn’t availability so much as it is adaptability.”
The country and the world have to buy into this, he explained. “As we have seen, public health has become a political issue rather than a health issue.” In time, he believes society will adapt similar to the way travelers have adapted to heightened airport security following 9/11.
From Trenkle’s perspective, public health agencies ought to be made aware of test results. “That data is very helpful to gauge the infectious rate and make local, national, and global recommendations,” he said.
According to Wells, though, the reporting of at-home testing is problematic. “You can’t have self-reporting of test results because that would skew any statistics,” he said. It isn’t useful for people to enter their own test results into a database “because we don’t track who buys these tests,” and, therefore, “don’t have the appropriate denominator.”
If people are testing at home instead of going to testing centers, that data is essentially lost. “That would hurt our country, state, and city efforts at knowing what the true prevalence of disease is out there,” he added.
Paul Nicolaus is a freelance writer specializing in science, nature, and health. Learn more at www.nicolauswriting.com.