Multiple positive LFT's and negative PCR's- which can be safely trusted?

[Rainbowgirl32]

I have had 7 positive LFT' s and 3 negative PCR's since last Sunday. Work told me to isolate as I had strange sense of taste for 2 days but it's driving me crazy not knowing for certain. I know at least 3 other families in Norfolk with the same issues in the last 6 weeks.
Am I unnecessarily leaving work in the lurch because I don't have it? Or am I keeping vulnerable people safe because I do?
I've researched for hours and LFT false positives are about 1 in 1000 because of high specificity so if your LFT is positive it is almost certain you have it www.gov.uk/government/news/new-analysis-of-lateral-flow-tests-shows-specificity-of-at-least-999
But PCR tests are the 'gold standard' and trump LFT's in official blurb.
Have you had any experience or answers to this confusing situation?

FYI I used Flowflex, but 3 different packs and tested as per instructions before food and drink, and a couple in the afternoon/evening, My DD tested negative every time.

The LFT is correct. The false positive rate for them is very low (assuming you have followed the instructions correctly).

I had this too with flowflex. Two positive lateral flows, but a negative lft of a different brand. PCR came back negative. Retested with the 2 brands of lft, and got one positive and one negative?.?.
No symptoms, so tricky !

Ah, the old flowflex positive pcr negative situation...something my son has too, despite multiple negative pcrs. Ive given up using them on him as it seems whatever we do he gets a positive result. I started a thread a while back, and have seen numerous others with the same issue.

I dont have any solutions or answers though im afraid, Im in SE England, and for a while wondered if there was a lab problem but it seems to be an issue with these lfts. I believe they are tested for cross reactivity with 3 of the 4 circulating other seasonal coronaviruses, so maybe picking the other one up? I really would love to know the explanation for all of these false positives. I agree that on the basis of a single pcr, I would be suspecting a false negative pcr rather than false positive lft, so Id always reccomend a second pcr of you are still testing positive.

Maybe we'll eventually find out why this is happening. I also saw a study somewhere showing that certain auto antibodies associated with autoimmune diseases like lupus, sjorgens syndrome etc can cause a false positive on certain lateral flows (other assays using the sane colloidal gold technology) so maybe this is a factor. I really dont know, I would really like to though, driving me nuts lol.

Just seen you have had 3 negative PCRs OP, sorry. Its absolutely something fishy with these tests.

Pcr is the gold standard. It's highly, highly unlikely you've got three false negatives with pcr.
Your LFTs are picking up something but not Covid.

My DH is the same. Been testing positive on lft’s, negative on two pcr’s. So frustrating. No symptoms.

Thank you all. Yep, driving me nuts too!
I don't know why they changed to flowflex, but if they think it's a better brand they might be shooting themselves in the foot. I've been a firm advocate of testing but my confidence has been shaken by uncertainty. I just hope its not as widespread as it looks, even just from on here!

I've emailed just about everyone I can think of too, including media just in case they've picked something up!

I had the same, but was also feeling unwell so decided in the end that I had it and isolated as it seemed the most sensible thing to do. Like you though, I found it very unsatisfactory as I don’t 100% know whether or not I’ve had it. LF carried on being positive for about three weeks and were then negative after that.

I had the same a few weeks ago. My son had Covid at the time and I had similar symptoms and was testing positive on lateral flows but did two PCRs a few days apart that both came back negative. Really wish I knew what was causing it. No one else in the family had issues with the lateral flows so it can't have been a faulty batch and I was testing first thing in the morning before I eating or drinking.

I commented on someone else’s similar thread the other day. I’ve had 4 positive LFTs (flowflex) and two negative PCRs since last Wednesday. Still testing positive and I have cold symptoms and tiredness. It’s so frustrating not knowing what the problem is - I’m starting to think there may be some cross-reactivity issues with this particular brand. But at the same time I’m keeping a low profile, as I wouldn’t want to give anyone Covid, if that’s what it is.

Yep happened to my dd twice in the space of about of a month. The only conclusion I can come to is maybe she had covid before and we didn’t spot it, and she triggers the LFTs when she’s poorly?
I won’t use them anymore on her.

Excellent, let us know if you hear anything!