False positive on lateral flow?

[BrutusMcDogface]

What are the chances?! A quick google hasn’t really given me any anecdotal evidence. It’s my child, not me. Booked pcr for tomorrow.

@BlackInk

This is DD’s, faint but definitely there and within the time limit…

Yes that is definitely there…. I find it all so odd!

False positive LFTs are very rare, in the sense that if you test people who do not have Covid then you will get very few positive results. Less than 1 in 1000 I think.

BUT the chance that your positive result on an LFT is false depends on the underlying rate of infection in the population. In a world where nobody has Covid, then ALL positives are false positives. In a world where everyone has Covid, then there are no false positives. When infection rates were at their lowest (summer last year?) then a positive was far more likely to be false than correct. That certainly isn't true at the moment given the higher infection rates.

I had one this weekend, positive on lft and negative on pcr

I don't think getting a false positive LFT is anything like as rare as "they" are making out. I have lost count of the number of times I have heard of people having a positive lateral flow followed by a negative pcr.

I had a positive LFT on Christmas morning. Didn't take a picture but it was clearer than the one posted on here - not quite as dark as the control but very obvious. Did a couple of other tests afterwards - both negative. PCR Boxing day - negative. No symptoms beyond typical end of term tiredness.

I've had positive lateral flows quite a few times but PCRs always come back negative 🤷‍♀️

Positive lateral flow twice and negative pcr's for me too .

Multiple positive lfts and three inconclusive pcrs. I think I had covid as son and husband has positive pcrs

@BrutusMcDogface

We did use a flowflex actually. No reflux. Just got to wait and see now 🤞

So many people, on mumsnet alone have had this experience with flowflex

The LFT was very strong!

Still waiting! Had pcr this morning. Rules do change tomorrow re: needing a confirmatory pcr but to be honest I actually want to go to work, so I’m hoping.

Not very common but can happen, my friend had positive LFT Christmas Eve obviously isolated until her PCR results came back the day after boxing day and she'd been negative all along!

A positive on LFT is many times more like to be true than a negative on PCR.

So receiving a negative PCR result does not make the LFT a "false positive."

Contrary to what the government have implied by making PCRs the "gold standard". This is one of the reasons for the ending of confirmatory PCRs if asymptomatic.

People say it’s rare but I’m another one, positive LFT and negative PCR. DH only had PCR because of my positive LFT and his PCR was positive 🤷‍♀️.

This was very recently too.

If you have a positive LFT followed by a negative PCR, the LFT is much more likely to be correct.

I have seen this graphic before, not sure of the source?

9 positive Flowflex lft results between 29th Oct and mid Dec, 5 negative pcr tests. Changed brands and no problems since then. Always faint positives but definitely there within the timeframe.

This was showed a clear line but pcr was negative- still had all the symptoms. I know it’s overflowed, one of us has a heavy squeeze but the previous overflowing ones have been negative if you know what I mean.

@Bussinbussin this actually happens often with the flowflex ones. Never seems to be any other brand. I've never had a positive of any other brand but them. I don't think 3 PCRs can be wrong. Even when I got the positives on flowflex other LFTs showed negative.

I've had 2 negative pcr tests but all my flow flex lfts since Christmas have been faintly positive. Took first pcr on Christmas day as lft had a 2nd line. Went for another pcr a week later as the lines got a bit darker.

Weirdly, I don't test postive on other brands of lft.

DD just got a negative PCR, been waiting for the result since Saturday and all LFT every day.
This is yesterdays LFT.
DD had exact same symptoms that friend from school had just before the return!

I have experienced the same with my daughter with flow flex. We all did lateral flows on Sunday as we have had a close contact develop covid. She had a super faint line, too faint to show up in photos, almost a grey impression where the line would be. This was followed by a negative pcr result yesterday but the same has happened with the flow flex this morning. The other 3 of us are clear. Will perhaps try an older style or a new box of flow flex tomorrow.

I’ve had 2 negative PCR, faint LF and my husband has covid at the moment. I think the LF is more reliable given the circumstances, from today I can take the LF as positive but before then the PCR would have been seen as the ‘correct’ result despite the LF actually being more reliable.

CalmDownBoris72 someone said similiar to me that even though DD got a negative PCR because of the rule change and still having positive lft that we should follow the LFT and keep her isolating.

Well, just to update you- ours was not false! Confirmed on pcr.

I thought the rule about not needing confirmation from a pcr was just temporary, due to supply issues? Who bloody knows!? 🙄