Some children have found a devious method to get out of school – using cola to create false positive Covid tests. How does it work?
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. [Videos of the trick have been circulating on TikTok since December and a school in Liverpool, UK, recently wrote to parents to warn them about it.] 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 on 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.