Abbott antigen test gets FDA nod as first at-home, virtually guided COVID-19 diagnostic

Dive Brief:

Abbott on Wednesday received FDA emergency use authorization for a 15-minute antigen test, making it the first at-home, virtually guided coronavirus diagnostic to get the agency's nod.
The BinaxNOW COVID-19 Ag Card Home Test, which requires a prescription, offers a telehealth service to walk users through the sample self-collection process and to help them read and understand their results. Abbott said the $25 cost for the test and service is the "lowest currently available for at-home testing" but warned that it must be performed "only with the supervision of a telehealth proctor."
Abbott's EUA comes a day after an antigen test from Australia's Ellume was authorized by FDA as the first COVID-19 diagnostic that can be purchased over the counter and fully performed at home — without a prescription. Some public health experts are questioning why prescriptions are being required for some tests, potentially limiting their availability as U.S. coronavirus cases continue to surge.

Dive Insight:

With this week's authorization of Abbott's and Ellume's rapid antigen tests, there are currently three COVID-19 diagnostics that can be fully used at home by consumers. FDA last month gave the green light for the first completely at-home coronavirus test from Emeryville, California-based biotech Lucira Health.

None of the three at-home tests are yet widely available. Abbott expects to deliver 30 million home tests in the first quarter of 2021 and 90 million in the second quarter. Ellume plans to produce more than 3 million tests in January and deliver 20 million to the U.S. within the first half of 2021, while Lucira said its COVID-19 test kit will be available nationally by early spring 2021 through healthcare providers.

Lucira's molecular test, which costs about $50, delivers results in 30 minutes or less with self-collected nasal swab samples. With a $25 price tag for its 15-minute antigen test, Abbott easily beats Lucira on those two features. Ellume in that regard sits in between with its $30 antigen test that delivers results in about 20 minutes.

The three at-home tests also differ when it comes to their respective authorizations for certain symptomatic and asymptomatic individuals. While the Lucira kit is authorized for people age 14 and older suspected by their healthcare provider to be infected with the virus, Ellume's diagnostic is OK'd for individuals with or without coronavirus symptoms and for individuals as young as 2 years old.

Abbott's BinaxNOW home test is authorized for those 15 years or older suspected by their healthcare provider of infection within the first 7 days of symptom onset, as well as adult-collected nasal swab samples from individuals ages 4 years or older who are likewise suspected of COVID-19 by their healthcare provider within the first 7 days of symptom onset.

The BinaxNOW COVID-19 Ag Card Home Test is a different product than the company's $5 point-of-care BinaxNOW COVID-19 Ag Card test that was authorized by FDA in August. The previous EUA only allowed for the rapid antigen diagnostic to be used by medical personnel or trained operators in certain non-clinical environments operating through a CLIA certificate.

FDA in Wednesday's Abbott EUA announcement noted that while antigen tests are "very specific for COVID-19" they are not as sensitive as molecular polymerase chain reaction (PCR) tests.

"This means that there is a higher chance of false negatives than with many molecular tests. Positive results from antigen tests, while generally highly accurate, may be subject to false positive results especially in areas where there are fewer infections," according to the agency.

Compared to lab-based molecular PCR tests, Abbott said data collected from four U.S. investigational sites showed that the BinaxNOW COVID-19 Ag Card Home Test delivered 91.7% positive agreement (sensitivity) and 100% negative agreement (specificity) in people 7 days or less post-symptom onset at all cycle threshold (Ct) counts, and 100% positive agreement (sensitivity) in people 7 days or less post-symptom onset with Ct counts of 33 or below.

According to Ellume, its at-home antigen test correctly identified 96% of positive samples and 100% of negative samples in a multi-site U.S. clinical study of both adults and children above 2 years of age. In people without symptoms, the test correctly identified 91% of positive samples and 96% of negative samples.

Lucira claims its at-home COVID-19 test is comparable to the PCR gold standard for detecting SARS-CoV-2 infections. The company contends its molecular diagnostic, which uses a method called loop mediated amplification reaction (LAMP), was able to accurately detect 94% of infections found by "one of the most reliable FDA authorized" PCR tests, and also correctly identified 98% of the healthy, uninfected people in a clinical trial.

Both the Abbott BinaxNOW COVID-19 Ag Card Home Test and the Lucira self-testing kit are currently authorized for prescription use only. Ellume's antigen test stands alone as an over-the-counter coronavirus diagnostic that can be used completely at home without a prescription.

However, Michael Mina, a professor of epidemiology at Harvard's T. H. Chan School of Public Health, has questioned why at this stage in the pandemic the FDA is even requiring prescriptions for some coronavirus tests.

"FDA has now conceded that COVID testing doesn't require a medical prescription. So the real question now is how can they continue to hold back these tests and require medical prescriptions for some tests, but not others? These are all COVID tests. There’s no reason to have this dichotomy existing now," Mina said during a Friday press conference.

At the same time, Mina contends that FDA's making the first at-home collection COVID-19 PCR test available with no prescription doesn't make much sense.

FDA last week authorized the first non-prescription test that requires a lab to process a home-collected sample. That nod went to laboratory giant LabCorp, which is selling the PCR test through its Pixel consumer website and may expand into retail channels.

"You can now get a COVID test from LabCorp without a prescription, without anyone telling you that you need it, but it’s going to take a while. You got to get the thing delivered. You have to use it to mail it back the next day and you get a result back three days later. So you’ve already wasted your entire transmission period. It’s never going to work for public health," Mina said.