Thread by @Telegraph

❓If lateral flows are 'so accurate', why are so many reporting confusing results?

We’ve asked experts how lateral flow tests and PCR tests work - and how to get the most accurate results

Thread 🧵👇
telegraph.co.uk/health-fitness…

🔎 A new peer-reviewed study shows lateral flows detect more than 80% of infections – regardless of whether people have any symptoms.

Yet anecdotally many are finding the tests unreliable

➡️ It’s a confusing picture, but the lead author of the study Professor Irene Petersen believes the fact that lateral flow tests detect infections without symptoms makes them the most effective for reducing infections

❓So what’s the difference between the tests?

A PCR is considered the ‘gold standard’ diagnostic test, with only 3.5% returning a false negative result

🧪 However, PCR tests look for fragments of ribonucleic acid left after an infection.

So they’re no good at identifying people who are actually infectious but not yet showing symptoms - who are thought to account for a third of transmissions

Lateral flow tests respond to a protein on the surface of the virus and can detect signs of infection before any symptoms emerge.

Unlike PCR tests, they don’t require processing in a laboratory and the results are available in around 20 minutes

🦠 It is impossible to tell the difference between a cold and Covid clinically, and it is possible for a swab to ‘miss’ collecting any virus

It’s mostly likely to happen if someone doesn’t insert the test deeply enough into the nasal cavity

➡️ Additionally, You may develop symptoms but still have a relatively low viral load – so there might not be enough virus for a positive result.

Not blowing your nose properly before the test also increases the chance of a false negative

😷 Professor Peterson says: “Apart from vaccination, lateral flow tests are one of the most powerful tools we have for stopping the infection”

Read the full story: telegraph.co.uk/health-fitness…