I finally got my hands on a Cue rapid COVID test device: https://shop.cuehealth.com/pages/all-products. Here’s a brief analysis and mini teardown:

The Cue is a molecular test similar to lab-based PCR tests and the Lucira check-it. They’re more sensitive than antigen tests, but at >$60 per test, for screening purposes you’re probably better off doing antigen tests 3x as often for half the price. Still, it’s interesting.

There is a nifty app that controls the device and walks you through the process.

Results take about 15 minutes.

The cartridge itself seems pretty simple, giving me hope that at scale perhaps they could be a lot cheaper. In 2014 they claimed Flu tests could cost about $10 each: https://www.theverge.com/2014/6/13/5801022/cue-hopes-to-be-your-portable-personal-health-testing-lab

It looks like there’s only a single reaction chamber with some sort of electrical sensor that sits above the heater in the reader. Fluid flows from two chambers, through the swab and into a sponge.

This is a fair bit simpler than the Check-it which has 8 reaction wells and a camera to watch the colour change. https://x.com/RickByersLab/status/1431076518579552260

I’m guessing it’s also RT-LAMP but with some sort of electrical measure of the pH change. But it claims to also test for human RNaseP, so a swab without a sample will return invalid. I have no idea how they’re obtaining multiplexing in one reaction well with no optics. Thoughts?

I managed to pry it apart further. The chip looks to be a 24C04, 4kbit EEPROM worth about $0.32 USD. So probably just for storing the cartridge serial number, maybe assay configuration parameters so the device can work offline with new tests.

I think that’s a ceramic heater under the swab. So maybe the metal pad in the reader is not a heater but an electromagnet! Maybe this is some sort of magnetic biosensor? Eg. https://pubs.acs.org/doi/10.1021/acssensors.8b00048#

Ah, according to this patent it’s probably a piezoelectric transducer for mixing the sample, not a heater.
Cool! https://patents.google.com/patent/ZA201800856B/en