We often write about digital home health devices. Since we launched Health Tech Insider, however, no other single force has advanced remote care and telemedicine as much as the COVID-19 pandemic. It’s fitting, then, that we finally have an at-home device that tests not just for COVID-19, but can also differentiate virus variants.

Researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University, the Massachusetts Institute of Technology (MIT), and Boston area hospitals developed an at-home COVID-19 diagnostic platform. The device senses nucleic-acid based biomarkers of infectious and non-infectious diseases using CRISPR technology (Clustered Regularly Interspaced Short Palindromic Repeats). The Wyss team named the device Minimally Instrumented SHERLOCK (miSHERLOCK). SHERLOCK stands for “specific high sensitivity enzymatic reporter unlocking. The platform is “minimally instrumented” because a user can diagnose COVID-19 without any other instruments or devices. There’s no need to send samples off to a lab for processing.

The Boston-based researchers explained how miSHERLOCK works in an article in Science Advances. To test for COVID-19, the user spits into a heated sample preparation chamber that contains two enzymes, DTT and EGTA. The saliva mix heats for 3 to 6 minutes during which it wicks into a filter. Next the user transfers the filter to an unheated reaction chamber. The user also punctures a water reservoir the activates the SHERLOCK reaction in the chamber. After 55 minutes the user looks into a window on the side of the reaction chamber. If COVID-19 DNA and RNA are in the sample, a fluorescent signal lights up. When they tested the miSHERLOCK platform with 27 COVID-19 patients and 21 healthy subjects, the device correctly identified COVID19 positive patients 96% of the the time (sensitivity) and patients who did not have the virus 95% of the time (specificity).

The device also successfully identified known viral variants when the researchers added synthetic variant viral RNA to healthy human saliva. According the published report, tests for new COVID-19 variants would take only about two weeks to develop. CRISPR technology works at a molecular level which, in this case, makes it easy to adapt to new virus forms.

The Wyss/MIT team estimate the miSHERLOCK device costs about $15 to produce, but the cost be as little as $3 with mass production. They also said the device files and circuitry designs are available publicly so anyone with a 3D printer can build the hardware device.

The miSHERLOCK test platform is exciting because it could lead to low-cost, in-home COVID-19 testing, and, presumably testing for other infectious and noninfectious diseases as well.