The newer versions of lateral flow tests (LFTs) instruct the user to swab the nose only when testing for Covid – and the change came as a relief for those who hated doing the gag-inducing throat and nose combo.

However, many have taken to social media to question whether the newer, simplified method is accurate.

Some people have even posted photos to show that they’ve received a negative test result when swabbing just the nose, but a positive result when reverting to the old method, meaning they need to isolate.

So, what’s behind the difference? Should we all be swabbing our throats again as Plan B restrictions ease? And why were the nose-only devices even put out in the first place?

My son (6) is positive for covid. So we decided to do a little experiment. On the left is a flowflex lateral flow test with just a nasal swab (as advised) - negative. On the right is a flowflex lateral flow test (same batch) where we swabbed the throat instead - positive. pic.twitter.com/uXJRd1aTPQ

We spoke to epidemiologist professor Tim Spector, of King’s College London who works on the Zoe Covid study, to find out more.

It’s not that the throat is more accurate than the nose, but that the throat and nose swabs are more effective together, Professor Spector tells us.

“There’s a slight random nature of whether the virus particles are presenting on a particular part of your mucus at any one time. And it’s not an absolute science that when you swab something you’re 100% definitely going to pick it up,” he explains.

“In general, the virus will present slightly differently in different people and so some people might have more virus in the throat than the nose. Other people might have more in the nose, and as different variants are evolving, it’s likely that they’re attacking different bits of the body with more success than others.”

There’s also the fact the some people might find it harder to do a good nasal swab, he adds, so they risk an inaccurate result if the test isn’t completed properly.

“Yes, do the throat first and then the nose,” says Professor Spector. “And then you’ve got a greater chance of finding out whether your cold-like symptoms are actually Covid or not.”

Professor Spector doesn’t have a clear-cut answer as to why the LFT instructions were changed from mouth and nose to just the nose.

“Perhaps it was to keep costs down or keep it simpler,” he tells us.

“Perhaps it’s got stuck in bureaucracy. And that’s why these rules have come about, but actually, clinicians will tell you it’s always best to get swabs from more than one site.

“In the current climate, with the current number of cases, we need to know results and I think it’s key to test both.”