BinaxNOW COVID-19 Ag Card is the Beginning of the End


Image of the test card from Abbott. No equipment or reader required.

Abbott’s new $5, 15-minute, 50 million per month test is a game-changer

This past week an eventful announcement came from Abbott Laboratories, manufacturer of several diagnostic platforms, including several already approved fro COVID-19 testing including amplification-based IDNow, and a few antibody automated systems, one prominent one being the Architect.

Now on their Binax platform, which in prior iterations received FDA approval with an Alere Binax Reader, this test under Emergency Use Authorization does not require any equipment, and qualified for a CLIA waiver.

The reason Bill Gates say all US testing were ‘garbage’

It was only a few weeks ago in a Wired interview, that he said that most US tests ‘were garbage’ due to the very long turnaround times, often five or 10 days or even longer to return results, after which contact tracing is not possible and the infected have already infected many others.

Thanks to no requirement from CMS for reimbursement in terms of timely return of results, laboratories running a backlog simply worked through them in first-in, first-out fashion. With over 42,000 new cases per day (7-day average) in the US as of this writing, and 963 average deaths per day, the number of tests per day actually has been drifting down, to about 700,000 daily tests.

Abbott’s goal: develop a test while building out manufacturing

In a truly huge, courageous bet, Abbott spent hundreds of millions of dollars to build manufacturing capacity for the BinaxNOW technology at the same time the test itself was being developed. Abbott says they will be able to manufacture ’10’s of millions’ of tests in September, and 50 million tests per month starting in October.

On this Abbott webpage (on the left side toward the top) is a link to sign up with your name, email address and zip code, and they will inform you when testing is available in your area.

Key differentiators that make this a game-changer

By making the test just a lateral flow assay without any dedicated hardware, the EUA qualified for a CLIA waiver which means it can be rolled out to a local drugstore (CVS, Walgreens) nurse station, your local doctor’s office or an urgent care clinic. For individuals within 7 days of symptoms, this $5 (list price) 15-minute colorimetric test is very simple.

The nurse takes a provided swab, takes an anterior nasal sample (from the front of your nostrils, not way back in the nasopharyngeal area). The nurse will then apply six drops onto the swab from a little dropper bottle, turn the swab in the card three times, and fold over the card and apply the adhesive strip, then wait for fifteen minutes.

Here is the FDA Instructions for Use (IFU) that has a lot of technical detail, in addition to brief protocol card at the end.

From the FDA IFU document

Of course, a nice video and one-page Fact Sheet (PDF) lay out the benefits very clearly.

  • Bring tests to where the people are
  • Make it cheap ($5 does count as cheap, compared to the $100 PCR tests)
  • Make is scalable to tens of millions per month (700K/day currently is 21 million this month, and the government has already purchased 150 million of them)
  • Make it easy to administer (CLIA-waived) and no additional equipment necessary
  • Make it accurate enough (BinaxNOW COVID-19 Ag Card is 97.1% Sensitivity, 98.5% Specificity
No batteries needed. Or expensive reader.

A little about the accuracy of this antigen test

Both BD and Quidel produce antigen tests for COVID-19 diagnosis under EUA, however the tests that run on their non-CLIA waived tests (that run on expensive equipment requiring relatively highly trained personnel in a CLIA environment) only will scale so much. Both companies claim they are working against capacity constraints, and aim to reach 7 million tests per month in March of 2021.

The accuracy of the BinaxNOW is very good, and under the conditions of the EUA (only for symptomatic individuals within 7 days of onset) this is reasonable. For a population with a low amount of infection, unleashing a test across all individuals would be a recipe for confusion, with 29 out of every 1000 people (2.9% false positive rate) being false positives.

However if it is only suspected, symptomatic individuals, this 2.9% false positive rate is acceptable, especially if reflex testing is available; the public health good in getting infected individuals into quarantine is a high priority to stop the spread.

(Edited to add these a few more paragraphs and the next two figures.) The technical sensitivity LoD is reported as TCID50/swab as 22.5, and the cross-reactivity against 14 respiratory viruses (including 3 coronaviruses OC43, 229E and NL63 that cause the cold, the 2 influenza viruses A and B, RSV etc) all at 1 x 105, in addition to 10 bacterial pathogens (Mycobacterium tuberculosis anyone?) On top of this, for interfering substances they used three over-the-counter nasal sprays for a total of 16 (including whole blood and mucus).

One note of interest was looking at 35 positive samples by both BinaxNOW and RT-qPCR and one false negative by BinaxNOW using qPCR as the comparator, it was with a Ct of 33 or above. (Data below.) As many of you know, qPCR is a semi-quantitative method not very helpful without a standard curve, but the IFU did not provide that information. It clearly prefaces this table is provided ‘for informational purposes’.

Comparing results against RT-qPCR

The table below is also provided – interesting that the two false negatives occurred on Day 5 of symptom onset with one individual, and on Day 7 of symptom onset.

False negatives as a function of Days since Symptom Onset

Both of these were obtained from this FDA document, the BinaxNOW instructions for use (aka “IFU”) (PDF).

A few more thoughts

As vaccines move forward, this is a great step that I believe will change the landscape of infection in the US. I myself was injected with Novavax / Emergent Technologies’ NVX-CoV2273 with a saponin-derived adjuvant as part of their Phase IIb testing, and I am very excited about it. Even though the Phase III may start in late September or October, it could be the first of the year that that they will start to be rolled out.

There are a few other efforts afoot to scale RT-qPCR testing from industrial sequencing factories like Ginkco Bioworks, Helix, and Guardant Health (the latter two have received EUA’s already for Illumina’s COVID-Seq technology on a special S4 NovaSeq flowcell), and Ginkco wants to do pooled saliva testing for elementary schools. In my estimation, this poses a high logistical challenge to get the samples to the centers for testing. 50 million additional tests per month means another 1.6 million samples delivered per day to the respective locations.

And these are not just gifts like at Christmas, these are potentially infectious samples that need careful handling. A locally distributed, easy to sample and easy to test solution like BinaxNOW makes sense.

Two more things: the test could be improved with adding a second detection antibody; the first one is to the Np (nucleocapsid) protein of SARS-CoV-2; an antibody to the spike protein could also be used.

Also, Abbott has developed a smartphone app to give a barcoded message of a negative result, for those who need a secure ‘all clear’ signal. Could come in very handy to have this capability at launch.

The Abbott Navica mobile app, with a negative test barcode shown

About Dale Yuzuki

A sales and marketing professional in the life sciences research-tools area, Dale currently is employed by SeqOnce Bioscienceshttps://seqonce.com as their Director of Business Development. For additional biographical information, please see my LinkedIn profile here: http://www.linkedin.com/in/daleyuzuki and also find me on Twitter @DaleYuzuki.

Leave a comment

Your email address will not be published. Required fields are marked *