Positive thread on LF tests

[bookworm1632]

www.bbc.com/news/health-56750460

Out of 26 MILLION tests, fewer than 1 in 8500 was a false positive!

That's MUCH lower than feared when they started testing schools - previous data indicated there could be as many as 4 false positives per 1000.

The other good news is the VERY low number of positives - 1 in every 1000 tests taken. This means that taken as a proportion of positive tests only, the number of false results seems high (18%), but that's deceptive.

Put another way - if your whole family of 4 took a test every day, it would be over 6 years before anyone in the family got a false positive.

Thanks for that! I think we're all very bad at getting perspective with all these statistics flying around.

False positives were never a worry. They put no one at risk. Those stupid tests are rife with false negatives though.

I’ll be approaching with caution with LF tests going forward. I have Innova for work, and had 7 negative LFs in the 24 hour lead up to my PCR test, which was positive.
It worries me that we are relying on these and a lot of people will be caught out by this

@Ofallthedays

I’ll be approaching with caution with LF tests going forward. I have Innova for work, and had 7 negative LFs in the 24 hour lead up to my PCR test, which was positive. It worries me that we are relying on these and a lot of people will be caught out by this

Why would you take 7 LF tests in one day? Why did you take a PCR test?

LF tests are NOT meant to be used by anyone with any reason to think they could be infected - that's what PCR tests are for.

LF tests are meant to be used by people without symptoms, who would otherwise NOT be tested so that any cases they do pick out are bonuses.

@ConstantlyChanging

False positives were never a worry. They put no one at risk. Those stupid tests are rife with false negatives though.

They were a huge concern.

3 false positives per 1000 would have meant nationally a LOT of families unecessarily self-isolating when mass school testing began.

It wasn't helped by the government insistence that a -ve PCR DIDN'T overrule a +ve LF, which was utterly wrong - thankfully they've U-turned on that now.

@bookworm1632 see this doesn’t make sense to me why people keep saying this. Surely if they pick up as-symptomatic cases they should pick up symptomatic l? Which I was on the morning of my PCR..which made me book it. Although I had none of the classic ‘symptoms’ that are listed when you go to book a test (which is another issue in my eyes).
Yes you’re right people should be booking PCRs if they feel they have ‘symptoms’, but not everyone will ...and will take the LFs as gospel. This needs to be advertised more instead of the adverts implying they are foolproof and a way to protect your family. Had I have done that I would have taken a lot of people down with me

[quote Ofallthedays]@bookworm1632 see this doesn’t make sense to me why people keep saying this. Surely if they pick up as-symptomatic cases they should pick up symptomatic l? Which I was on the morning of my PCR..which made me book it. Although I had none of the classic ‘symptoms’ that are listed when you go to book a test (which is another issue in my eyes).
Yes you’re right people should be booking PCRs if they feel they have ‘symptoms’, but not everyone will ...and will take the LFs as gospel. This needs to be advertised more instead of the adverts implying they are foolproof and a way to protect your family. Had I have done that I would have taken a lot of people down with me[/quote]
Well I'm certainly the last person who's going to try to defend the government's often shoddy messaging on this...

Think of it this way - let's say you're in charge of a building with 1000 people in it and you have a daily allocation of 10 PCR tests, but practically unlimited LF tests. You are required to try to identify as many covid +ve people as possible. What do you do??

The answer is you restrict the PCR tests to those MOST likely to have covid, and the easiest test for that is symptoms. After that, well you may as well use up your LF tests to see if you can weed out any more - at best you'll only pick up half the asymptomatic cases, but that's not the point. The ONLY way to ensure you got ALL +ve cases would be to PCR test everyone every day and you don't have enough tests.

That's the situation the government's in except instead of 1000 people, it's 67 million....

As for the whole use of the word "safe" with regard to covid - it's just infuriating. It presents the issue as binary - this is safe, this is unsafe. In reality it's all about risk management. e.g. The only covid-safe workplace is one in which everyone is professionally trained in how to use PPE and wears full PPE including goggles and carries their own air supply.

I also agree on the "classic symptoms" thing. Initially it made sense because we were just coming out of winter and there were plenty of colds going around and with limited tests you're back to the above.... but now it should be made clearer that frequently covid presents itself with cold-like symptoms - runny nose, sneezing etc.

I think the problem is the false negatives. Always known false positives were not worth worrying about.