A prototype device has been created, measuring an inch wide, one that connects to a host device over Bluetooth and drawing power from a smartphone’s charging port. After opening a companion app, the sensor requires a particle of saliva to be deposited for a reading.https://appleinsider.com/articles/20/05/18/covid-19-sensor-could-bring-daily-testing-to-iphones
DNA strands in the virus bind onto proteins on the sensor, in turn creating electrical resistance and triggered a positive result in the app. Once a test is completed, the sample can be destroyed using an electrical current, leaving it ready to be reused in another test.
Thing is, this test relies on saliva. I happen to work for a company that did a ton of work on the viability of testing for COVID-19 using saliva. The results were not promising.
In the Diagnostic Cohort, we find that saliva collection has reduced sensitivity (~30% less) relative than NPS. And in our convalescent cohort of patients greater than 8 days and less than 21 days from first symptom, we find that saliva has ~ 50% sensitivity relative to NPS. Our results suggest that rigorous studies in the intended populations should be performed before large-scale screening using saliva as the test matrix is initiated.https://www.medrxiv.org/content/10.1101/2020.05.11.20092338v2
The team at Helix did some hard work and I wish the conclusion was different. If the sophisticated instruments and rigorous methods they used for testing showed that saliva isn’t as viable a medium for testing as NPS swabs, I’m hard-pressed to see how a $50 gadget with a tiny saliva sample can provide an reliable result. Maybe I’m missing something.