Karl Zelik Profile picture
Professor @VanderbiltU. Co-Founder & Chief Scientist @HeroWearExo. No longer active on X. Find me at: https://t.co/wOUTdP3t0H or https://t.co/PeYDtfqMh1

Jun 26, 2020, 5 tweets

Whoop recently reported a "Novel Algorithm Capable of Identifying 80% of Symptomatic COVID-19 Cases" using #Wearables.

Interesting study. Glad they're exploring & sharing findings.

But what caught my eye were the low Sensitivity values reported in the study preprint...
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I'd love to get input/perspective from folks w/ experience/expertise in diagnostic & screening tests.

Thoughts? Comments? Implications of this level of Sensitivity? 

Basically: Is the algorithm promising? Why or why not?

Here's link to preprint:
medrxiv.org/content/10.110…
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For those unfamiliar with Sensitivity and Specificity of diagnostic or screening tests, here's a nice 3-minute video introduction:

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Also here's a diagnostic test calculator. You can plug in Sensitivity & Specificity values (e.g. from preprint Table) with sample size & prevalence of disease. Helps you to visualize false positives & false negatives, or do quick though experiments:
araw.mede.uic.edu/cgi-bin/testca…
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Example: Assume 1000 people w/ Covid prevalence of 3%. Imagine a test has 25% Sensitivity & 95% Specificity. Test would correctly flag 8 (of 30) people with Covid, but falsely flag 48 people who were healthy. So out of 56 positive tests, only 14% would actually have Covid.
5/5

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