Kids are using soft drinks to fake positive COVID tests — I’ve worked out the science and how to spot it

Children are always going to find cunning ways to bunk off school, and the latest trick is to fake a positive COVID-19 lateral flow test (LFT) using soft drinks. So how are fruit juices, cola and devious kids fooling the tests and is there a way to tell a fake positive result from a real one? I’ve tried to find out.

First, I thought it best to check the claims, so I cracked open bottles of cola and orange juice, then deposited a few drops directly onto LFTs. Sure enough, a few minutes later, two lines appeared on each test, supposedly indicating the presence of the virus that causes COVID-19.

It’s worth understanding how the tests work. If you open up an LFT device, you’ll find a strip of paper-like material, called nitrocellulose, and a small red pad, hidden under the plastic casing below the T-line. Absorbed to the red pad are antibodies that bind to the COVID-19 virus. They are also attached to gold nanoparticles (tiny particles of gold actually appear red), which allow us to see where the antibodies are on the device. When you do a test, you mix your sample with a liquid buffer solution, ensuring the sample stays at an optimum pH, before dripping it on the strip.