Things You Most Likely Didn’t Know About RATs

Peter Steven Ho
4 min readFeb 3, 2022

Something to think about the next time you get a RAT test.

Photo by Annie Spratt on Unsplash.

Everyone has seen one and there’s a good chance you’ve even used one yourself. In fact, I used a rapid antigen test (RAT) just the other day.

I said to my wife, “What a simple and ingenious little device”. And she said, “They’re not that special, they work just like the device for a home pregnancy test.”

[Microphone drops]

And, of course, she’s absolutely right!

I just hadn’t made the mental connection that they’re based on the same technology. Naturally, this piqued my curiosity and I had to find out how RATs work.

I’ve left out a lot of the technical jargon, so here’s a simple explanation.

The key component (or the “magic”) in a RAT kit is the lateral flow device (LFD). That’s the plastic device you squeeze your liquid sample into and wait for the lines to appear. The device is completely self-sufficient and it has all the required reagents in the device to do the test.

Once you add your sample to one end of the device (via the hole), a porous material wicks the sample along the strip to the other end of the device.

Sandwich assay and two line LFDs

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Peter Steven Ho

BSc (Hons), LLB. Freelance writer in Technology, Science and Travel. Come join me on a journey of discovery.