Updated: Aug 15, 2021
On 8/26/20, the FDA announced Emergency Use Authorization (EUA) for the new Abbott antigen test BinaxNOW™ COVID-19 Ag Card that tests for qualitative detection of nucleocapsid protein antigen from SARS-CoV-2 in nasal swabs. The test will be given as a point-of-care test by a trained health care professional affiliated with authorized laboratories and patient care settings and is "authorized for use in patients suspected of COVID-19 by their healthcare provider within seven days of symptom onset." The test takes 15 minutes.
Abbott purports this test to be “rapid, reliable, highly portable, and affordable” while claim it will be useful for “detecting active coronavirus infections at massive scale.” The company also goes on to say that it can ship 50 million kits in October (approximately 10x the scale of the current antigen kits). Additionally, Abbott reported the BinaxNOW COVID-19 Ag Card demonstrated sensitivity of 97.1% (positive percent agreement) and specificity of 98.5% (negative percent agreement) in patients suspected of COVID-19 by their healthcare provider within the first seven days of symptom onset. Abbott will provide a free app that will give bar-coded access control depending on the results of the test. Finally, for good measure, it will list for only $5.
Many impressive features were demonstrated in this press release. The accuracy appeared strong, albeit with a small number of individuals. The cost could be cheaper than other antigen tests. Abbott is predicting a larger number of products can be shipped here than for other antigen tests. Its app for access control could be used in multiple use settings where documentation of negative test is deemed important.
So has the Covid-19 equivalent of sliced bread just been invented??
Not necessarily. This test showed value in having a quick turnaround in Covid-19 testing without needing a laboratory as it can be read from a testing card. However, the world is probably most hungry for a great product that can screen asymptomatic patients for Covid-19 so societal normalcy can be regained and the test is not technically approved for that. It may be used for the off-label indication of asymptomatic screening like other antigens have been but we do not know the value of the device in this population. This Abbott press release did not indicate the clinical condition of the studied population which is very important in understanding its value. This antigen test showed high sensitivity but we do not know how symptomatic the positive patients were or how asymptomatic the negative patients were. Since these patients were seen in a clinical setting, many of the patients were likely in a symptomatic category although these data were not enunciated. That could mean that the test only picked up highly symptomatic patients as well as the corroborative test but these specifics are not known. Viral loads may be less in asymptomatic patients with Covid-19 infection or in patients needing screening for other reasons so further studies may give diminished results.
Where else can the statements on the press release be fall eventually short? The main area is in accuracy. As always, real world data could yield lower sensitivity and specificity numbers in less controlled patients with variable symptoms. Results need to be borne out in larger populations. Manufacturing capabilities have to be as promised. Abbott has already overpromised at least once in this pandemic in Covid-19 testing. An NYU study showed that an earlier Abbott product missed half of the infections it was trying to detect, a disastrous shortcoming. Simply, health professionals outside the study context need to validate the process.
Even if the data were sound, the Covid-19 crisis is not over. This study only yields a clinical result at a single time point. One point in time is valuable as a one-time screen however the need for symptom monitoring and vaccinations remain. While some claim daily testing will be the key to ending the pandemic, cost and distribution of tests may this scenario an impracticality. Missed disease means undetected Covid-19 infections which in super spreader situations yields disaster. Also, in situations where the results do not correlate with the clinical condition in patients, a standard naso-pharyngal PCR test may be necessary. Even if Abbott can ship its full number, distributions to need are always a concern as well.
So is this study a big deal? Potentially yes, if the gatekeepers and stakeholders use the test properly and its validity holds up and Abbott can deliver on product. This product could be important for a potentially troubling flu season. Stay tuned!