Lateral flow tests are just not reliable...

[MariaAngustias]

Started feeling slightly unwell 6 days ago - just bit achey, headache, sore throat. Did daily laterals and all negative. 3 days ago felt quite ill, went to bed, high fever, sore throat, cough... lateral flows still negative. Yesterday did 2 lateral flows both negative, sent PCR off 3 days ago still no result. Today did lateral which lit up positive straight away.
So - is it normal that these tests lag days and days behind before they test positive? I am triple vaccinated btw - does this make any difference in the lateral flow showing a positive. Thank God I am vaccinated cos I feel like death warmed up. Would be interested in hearing others experience of the lateral flow tests x

On the weekend of 18th/19th December I had 2 faint positive LFTs and a negative PCR. My next LFT on Monday 20th was negative.

67% when asymptomatic, 75% when symptomatic, according to an article on the Zoe app.

This ^

LFTs are for asymptomatic testing. They are a great way of mass testing the population to catch a lot of cases that would otherwise be missed. If you have symptoms or have been exposed to somebody who is positive, you need to take a PCR.

I think they work when viral load is higher. My friend does the ONS testing and she was routinely tested on 23rd, lateral flows all negative but positive result came back yesterday. Today was the first day a lateral flow was showing as positive which is 5 days after the PCR was done.

I’ve been doing lateral flow tests since the 23rd when people from work started testing positive. They have all come back negative so far. I started with symptoms yesterday so have had a pcr this morning but lft’s are so far still coming back negative

DD has been testing daily with LFTs - all negative. Did a PCR as notified she was a close contact and the PCR is positive.

They are hit and miss. Lft was positive for me before symptoms starting despite having a negative pcr just the day before (was a close contact and testing regularly). Was similar for Dp.

They shouldn't be relied on though. You should have had a pcr 6 days ago. The reason why it's spreading is because people are relying on lft's for false reassurance.

We caught it off someone who thought they 'just had a cold' because their lft's were negative when they actually had covid and the lft's weren't detecting it.

The issue with lft's has always been that they need high viral loads to work.

You may test positive on one if you have good technique and have an active infection but some people won't test positive in the early stages or early days of symptoms. Apparently some people never test positive on them. I expect these people have poor swabbing technique or a low viral load.

Plenty of omicron outbreaks of people going to events based on negative lfts then turning out to be infected followed by a few days later with most of the people there.

But with pcr's so hard to get at the moment what choice do people have but to use them.

Up to 50% of negatives are false negatives, and a smaller % also of false positives with them

inews.co.uk/news/lateral-flow-tests-omicron-covid-variant-detection-testing-kits-1374073

What makes you think they don’t work? They detected your covid. They’re best when you’re most infectious.

There was a nice graphic from twitter showing how pcrs and lfts differ in their ability to detect covid.