Fact or cap: Can you fake a positive Covid test with lemon, kiwi, and other foods?

We tested a bunch of items to find out if there’s any truth to the controversy

The kids of TikTok are at it again, the papers scream. This time they’re using food and drink to fake positive Covid tests so they don’t have to go to school.

Smart. Well, obviously, having to self-isolate for two weeks when you don’t have Covid isn’t very smart, but you know. They’re using lemon juice, coca cola, and kiwi fruit. TikTok is awash with fact-or-cap videos of people trying to trick the lateral flow test.

The @.fakecovidtests account has 22.2k followers, while the #fakecovidtests hashtag has 6.6 million views.

Everyone’s up in arms. But is the panic valid? We tried the different methods floating around the internet on some lateral flow tests. Before we start, please take in the very obviously disclaimer that – and we really shouldn’t have to tell you this – you shouldn’t fake a Covid test during the pandemic.

The method

First, the method. People on TikTok, including the @.fakecovidtests account, tend to swab the fruit and then combine it in the vial.

But if you’re going to swab the fruit, why not just put the juice straight in the vial?

Our method was as follows: combining lemon juice in the vial with the test liquid, and then dropping that onto the sample area of the lateral flow test.

After that, like Wayne Lineker, we’re hoping for the all-important second line.


The classic, the OG. Old reliable citrus. We squeezed a lemon into a clean shot glass, poured a bit into the test tube, and then piped a few drops onto the test.

But nothing happened after 20 minutes. Even the control – or “C” – line, which shows the test is actually working, was absent.


I used rice wine vinegar because I don’t live in a chip shop. However, it’s still acidic so it should work the same as malt vinegar.

Nothing happened, even after 30 minutes. There may have been a very, very faint “C” line, but nothing definitive.

Kiwi fruit

Mixing the kiwi juice up with the test liquid produced a liquid that looked a bit like Shrek’s cum, so things were promising.

The control line showed up quickly, but even 30 minutes later it was not joined by the second line.

Coca Cola

I used full-fat Coke because I’m hard.

A single line showed up quickly, and things were promising. But yet again, it was left on its own.

Lemon, the second go

Lemon is the main contender, the focal point of all the outrage. So, undeterred by the absolute lack of anything happening, we decided to try a different method: just putting the juice straight on the sample bit.

After all, the spirit of scientific enquiry is experimentation.

Bluntly, nothing happened.

Lemon, the third go

Perhaps the problem is that there’s just too much of the sample. Maybe the lemon juice overwhelms the test. As a last resort, I tried the exact TikTok method – swabbing a lemon.

By this point in the experiment, I was feeling a bit ridiculous. So it didn’t help that, while I was swabbing the most intimate parts of a lemon, “At the River” – the sexy M&S advert song – came on shuffle.

‘Billy Corgan, Smashing Pumpkins’; ‘Greg Barradale, Swabbing Lemons’

Anyway, I say that because without that, there would be nothing to say here. Not a single line appeared.

San Pellegrino

Desperate to try something else and to explore the apex of acidic fizzy drinks, we tried San Pellegrino limonata. It’s the drink of choice for the type of person who would willingly self-isolate because it meant being doted on by Mummy.

As you might expect from a premium product, it was the most promising result yet, producing a faint second line. But it’s a waste of San Pelly if you ask me.

The inescapable conclusion is that if you really wanted a fake positive result, you’d just get a felt tip pen and draw the line on.

What’s the actual science?

Back in January, people were arguing that the fact the tests could be fooled was proof they didn’t work at all – which is silly.

“It’s a bit like saying your fire alarm is not very accurate because when I hold a lighter under it, it goes off—but there isn’t a fire in the house,” scientist Dr Alexander Edwards told fact-checking website FullFact. Great analogy.

It also obviously doesn’t mean these everyday items have Covid.

In fact, FullFact concluded that the foods probably produced a positive result because they were very acidic.

And for school pupils to isolate, they need a PCR test after a lateral flow test – so it seems like faking a lateral flow test is a bit pointless.

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