Anyone else get false positive LFTs? Worried about the new rules' impact on time off work

[LFTquestion]

DH repeatedly gets false positive LFTs (later negative PCRs). This is the fourth time now, and we are really fed up. Each time it requires a couple of days off work while he waits for the PCR results. It has happened pretty much every month since October.

He is triple jabbed and has never had Covid (that we know of!).

However, from next week, if he gets a positive LFT while asymptomatic, he is presumed to have Covid and will have to have a week off work.

But clearly, the odds are that these positive will be wrong!

He is a key worker and taking one week off every month isn't sustainable. He has to do LFTs twice weekly and provide proof of them to work, so simply not doing them isn't an option.

Has this been happening to anyone else? What's the plan??

Toooutthere I thought it was only if you used the coke to test (ie poured it on the testing strip), not if you just drank it.

I drink an appalling amount of coke, morning, noon and night. But I've never had a positive LFT (well, apart from the one which did pick up my actual Covid, that is!) It's Diet, I wonder if that somehow makes a difference.

I do all the time!

@Iggly

However, to those of you saying "oh yeah I had one last month", please note that a positive LFT followed by a negative PCR result is most likely (7-8 times more likely in fact) to be because the PCR result is wrong

Each time it happened to dd, we had two PCRs (and in one case three) spread out over a few days. So it was most definitely not the PCRs were wrong.

And the rest of us were fine.

Snap

I have noticed my dh and da flow flex going positive several hes after testing so I know we don't count it but it happened with one batch and hasn't happened before
The whole bit goes pinky and then both lines showing
I often leave them around to register later and this never used to happen

This has happened to me four times since September! Perhaps the first time I didn’t conduct the test under laboratory conditions, but I can say that on the next three occasions I followed those tests to the letter.

No answer, just following for advice and ideas really, as it’s basically happened every time I’ve had a cold this winter so far. When I actually did have Covid in December I was stunned: didn't believe that it could possibly true after four sets of apparently FP PCRs!

@DeclareThePenniesOnYourEyes

This has happened to me four times since September! Perhaps the first time I didn’t conduct the test under laboratory conditions, but I can say that on the next three occasions I followed those tests to the letter.

No answer, just following for advice and ideas really, as it’s basically happened every time I’ve had a cold this winter so far. When I actually did have Covid in December I was stunned: didn't believe that it could possibly true after four sets of apparently FP PCRs!

People have insisted that the PCR must be wrong and I did have Covid but I had bad cold symptoms and sore throat with two negative PCR and one faint positive LFT. All other LFT negative.

Can LFT pick up other colds? I thought this was meant to be extremely rare

Or - i did have Covid but extremely low viral load? Whole family exposed to me and all negative

@blameitonthecaffeine

Oh, wow.

When our headteacher at school announced this change she said that false positives on lateral flows occurred on fewer than 1 in 1000 tests so it would be fine. This is so clearly not the case judging by this thread!!

There's a rumour going round our Year 10s that the children at another school down the road have worked out that if they buy aloe vera drinks from the newsagent next door before taking their test it will be positive. I assumed the rumour was either fake or wrong but maybe not! And, if true, those kids that do this will now buy themselves 7 days off school instead of 1-2!

MN threads can be very self-selecting so i wouldn't necessarily conclude that 1-in-a-1,000 is wrong, though by some biological quirk the erroneous results seem to be focussed on some individuals. For instance, threads on high earners are full of people in the top 1% income bracket...

@treeflowercat are you saying we are talking BS? You've no idea how much drama the positive lines have caused us at home. Only happens to me, never seen a hint of a line with my DD or DH.

I don't know why I still believe the positives as it means I've pretty much had covid since November with no symptoms and PCRs don't pick it up - I've had about 6 in the last 2 months! (I've had it before in 2020, confirmed by PCR, close contact and symptoms). I also get negative LFTs when done later in the day, usually. Once or twice still a line.

It means cancelling childcare plans with my DM, pulling DD out of nursery, driving half an hour to PCR test site, and so much angst as I hated having covid and I don't want my 3yo getting it again. I'm also the least likely to get it as I wfh and don't go anywhere!

It really happens!

@itsacovidxmasone do you use mouthwash in the morning?

[quote Postdatedpandemic]@itsacovidxmasone do you use mouthwash in the morning?[/quote]
Once I did, didn't do it again. Wondered if it had a similar effect to vaping?

One morning I did it within 15 mins of waking up and the line came up within 10. Wonder if I'm just really acidic! I did speak to the GP about it as started to worry the tests were picking up something else concerning.

@itsacovidxmasone

• @treeflowercat are you saying we are talking BS? You've no idea how much drama the positive lines have caused us at home. Only happens to me, never seen a hint of a line with my DD or DH.*

I'm not saying that at all. All I was saying is that threads don't tend to representative of the population. If you're having problems with repeated positive LFTs then you'll be far, far more likely to engage with this thread.

Given your experience, why not just do your LFTs in the afternoon/later in the day? You're making an unnecessary rod for your back!

Yup I've learnt that lesson although this week still got a faint positive in the late afternoon. The next day, late morning, it was totally clear. I don't test unless I absolutely have to as it just fires up my anxiety, god knows why as it's heading to 'boy who cried wolf' territory!

[quote treeflowercat]@itsacovidxmasone

• *@treeflowercat are you saying we are talking BS? You've no idea how much drama the positive lines have caused us at home. Only happens to me, never seen a hint of a line with my DD or DH.

I'm not saying that at all. All I was saying is that threads don't tend to representative of the population. If you're having problems with repeated positive LFTs then you'll be far, far more likely to engage with this thread.

Given your experience, why not just do your LFTs in the afternoon/later in the day? You're making an unnecessary rod for your back![/quote]
Or maybe some actually properly explain, someone who is well-informed, as to how false positives actually happen.

I haven’t been able to find anything from a credible source - by that I mean the manufacturer or government scientists - as to why this is happening?

I think it’s the brand of test as it’s never happened with any other test. My DD is 10, she doesn’t vape, doesn’t have reflux, doesn’t drink coke. And it happens morning/evening. And when she’s under the weather (hence the LFTs!).

I’ve not made sense - I mean can someone knowledgeable actually explain it

My DC got a positive LFT just before xmas, and the PCR came back negative

One of my DCs has this. Two positive faint lines on LTFs followed by two negative PCRs. Then a few weeks later another faint positive LTF followed by a negative PCR. It's really stressful because I need to test before visiting family this afternoon but my poor DC's whole afternoon will be off if we get another line. Then back to the PCR place. Then wait. Then negative PCR days later. Although I've managed to get hold of some Orient Gene ones instead of the Flowflex so I'm hoping it doesn't happen with those.

It's actually really really shit because I feel totally stuck in that I feel I can't NOT test and potentially put others at risk. But also they just don't seen to be accurate for my DC for some reason. None of the rest of us have had this issue - either negative LTFs or positives which have been confirmed with PCR. So it seems to only happen to the same person each time.

It happens to one of my DC too. Faint second grey line on EVERY Flow Flex test they have ever done. Doesn't happen on any other brand of test.

DC has had covid, so I've seen what a proper positive LFT looks like for them. This faint second line happens every time for them though. Doesn't happen for anybody else in the family. Initially we followed up with a PCR but have given up with that now.

We've been given a stash of nose/throat tests but not sure what we'll do when they have gone. Luckily she's primary school aged, so the testing is done at home and not at school where they might not believe this happens every single time!

@HipHopBanzai my DCs are very faint grey lines too. That's good to hear it only happens on Flowflex. Think I'll abandon those now and hope the others work better. I wonder what it is that causes those lines. Something that must be specific to them and not the rest of us.

@RoxieLoxy

One of my DCs has this. Two positive faint lines on LTFs followed by two negative PCRs. Then a few weeks later another faint positive LTF followed by a negative PCR. It's really stressful because I need to test before visiting family this afternoon but my poor DC's whole afternoon will be off if we get another line. Then back to the PCR place. Then wait. Then negative PCR days later. Although I've managed to get hold of some Orient Gene ones instead of the Flowflex so I'm hoping it doesn't happen with those.

It's actually really really shit because I feel totally stuck in that I feel I can't NOT test and potentially put others at risk. But also they just don't seen to be accurate for my DC for some reason. None of the rest of us have had this issue - either negative LTFs or positives which have been confirmed with PCR. So it seems to only happen to the same person each time.

Why not explain to family and just not test.

Sorry, when I said "for people saying 'I had one last month'" I meant if you've had a positive LFT followed by a negative PCR once, that is much more likely to be a failure of the PCR process rather than the LFT being wrong.

I agree though, I haven't seen any proper explanation of why this seems to happen continually for a few people ('a few' as in, relative to the millions of people using them across the UK currently).

I suspect as this is now going to become a more important issue for people they will have to investigate it?

Interesting to hear about the mentions of connection to reflux.

So many people are quick to dismiss the well meant information about flowflex false positives, but for every one who does there are at least 3 who have experienced it - so maybe it's true.

Our false positives aren’t grey, they’re pink

@vickyc90 I have and they're all ok with it but my worry is what if it then is a real positive. I feel like we don't have a reliable way of checking at home. Although I'm about to try a different brand so hoping that might be ok.

Just to add, the Flowflex have been great at detecting our real positives too and I feel confident using them for the rest of our family. They have worked well for the rest of us even with asymptomatic cases. It's just the one DC who gets the faint grey lines.

Negative on the Orient Gene brand. Phew Will see if i can get hold of more of those.

Worth a try for anyone else always testing positive on Flowflex.