How Affordable At-Home Testing for COVID-19 Could Make a Difference

Imagine if you could spit on a piece of paper, in the comfort of your home, and find out in ten minutes whether you have COVID-19, the infection associated with Sars-COV-2.

Imagine if that test was so affordable, that school kids could be tested each day before school, college students before going to class, employees before going to work, diners before entering their favorite restaurant… you get the idea.

Such an affordable, ubiquitous, and accurate test would change the current paradigm dramatically, creating a more certain and secure environment.

Sounds too good to be true, right?

Several academic research labs (listed in this NYT article) have already made successful prototypes of paper-strip tests, and hopefully with some encouragement from the Food and Drug Administration, these tests will soon be made available to everyone.

Here are some key points that you should know about paper-strip tests:

• These tests detect viral antigens, via a strip of paper saturated with monoclonal antibodies. Results of these test are obtained in 5-15 minutes. Each test would cost $1-5, if approved by the FDA.
• The most commonly used COVID-19 test in the U.S. is the RT-PCR (Real-Time Reverse Transcriptase PCR). This test uses a nasal swab at a testing center and is very sensitive. It can detect viral particles even after the patient is no longer infective. Test results are available 3-9 days after submission. This may be after the patient has recovered, and possibly after they have spread the illness to others. Each test costs $50-150.
• Ct Values reflect viral load in a patient specimen. A low Ct value reflects a high viral load and is correlated with a higher rate of infectivity. The reason you need to know this is to better understand the research lingo about testing.
• An article by researchers at the New York Grossman School of Medicine discouraged use of this technology when they found that the Abbott ID Now test was only about 50% accurate. However, if you take a careful look at their results, you will find that false negatives of the Abbott ID Now testing were linked with high Ct values (low viral counts), which were unlikely to represent patients with transmissible infection.

Furthermore…

• The threshold of transmissibility is now known to be more narrow (viral loads need to be at or below a specific Ct value). This means that a less sensitive test, such as a paper test, utilized frequently, even daily, if affordable and widely available, may be the key that helps us contain the virus.  
• The CDC recently announced that 9 out of 10 people infected with the virus are never diagnosed. It makes sense that a person who expresses very mild symptoms, such as mild fatigue and nasal congestion, might dismiss these symptoms and not bother going to a testing center. 
• Current testing is catching 5-10% of transmissible (infectious) cases. Increasing the frequency of testing with a less sensitive test could bump that statistic up to 85% of transmissible infections.

To sum up…

This is the best news about managing the coronavirus I have heard yet. An affordable DIY test could make the difference between my kids’ schools staying open or having to revert to dreaded online instruction.

The bad news is that, even though we have the technology to produce millions of these tests in a short amount of time, it won’t happen until government agencies embrace the utility of the inexpensive, less sensitive test. 

As the NYT Opinion article (cited above) states, “Hope needs to be replaced with surety.” As we send our kids back to school this fall, we need to feel confident about their safety and rather than, “I hope my kid is safe…” say, “I am confident that my kid is safe.”

Want to know more?

1. Read A Cheap, Simple Way to Control the Coronavirus, an Opinion article in the NYT, by Laurence J. Kotlikoff and Michael Mina for a quick overview.

2. Watch this short video by Dr. Roger Seheult and MedCram for more details.

3. Watch this deep-dive interview of Dr. Michael Mina by the YouTube series Virology for even more information.

If you have been tested for coronavirus, I would be interested hear about your experience. If you have thoughts to share about this post, please do!