Positive LFTs but negative PCR twice

[DaxtheDestroyer]

So confused! My DC tested positive on an LFT, we booked a PCR which was negative. When we got the result we checked with another LFT (completely different batch) which was even more strongly positive. Repeated PCR - negative again.
So what's going on? There must be something causing the positive LFTs, there are loads of cases at school at the moment. Anyone had this happen? Just so confused as to what's the right thing to do

@Yellow85 the antigen LFTs test for is technically the protein on the surface of the virus - it's part of the virus, not produced separately when someone is infected. The PCRs test for the RNA of the virus which again is part of the virus - they're both tests for presence of the virus, with the PCR being more sensitive.

Antigen refers to anything that causes an immune response in the body (not what is produced by the body); pathogen is just another word for the virus itself. The stuff the body produces when infected (eg immune chemicals like cytokines and eventually antibodies) are totally different.

I'm following this with interest. I know of a few kids now who had covid symptoms, positive lfts and then negative PCRs so went back to school with their parents saying it must be a cold. I'm actually quite glad my DD has had covid and is now fine and back at school because at least we're spared that dilemma for a while.

I think something odd is happening with PCRs but I'm not sure whether it's new or it's just that we're noticing it more now because of the routine school testing and massive number of cases in schools.

I’m in the South West and have been wondering if something is up with the PCR.
My 12 year old son had a mild cold like illness but I am really ill cough, high temperature etc. Both negative on pcr. Yet my partner who has had covid in the past is fine. Weird.

I'm adding all the testing details onto the covid Zoe app and I'd encourage everyone in the same position to do the same so at least the data is being collected for analysis

We had the same thing (not South West!). Positive LFT results, but negative PCR for both DH and I. Someone we know was told that the testing centre we used is ‘having problems’ so we have just had second PCRs at a different one, but I don’t know what they will say. We have lots of symptoms including today loss of taste and smell.

DH has just had his 2nd PCR result and it's positive, following a negative PCR the day before and several positive LFTs. We only retested because our school asked us to.

Same here, also southwest, Bristol lab I believe ours go to.

DS2 tested positive on LFT Monday, lost sense of smell. Negative PCR the next day. Still positive LFTs so another PCR done yesterday by post. Waiting on results.

DS1 very strong positive LFT on Wednesday, PCR done yesterday. Waiting on results.

I feel ill, faint positive on LFT yesterday, waiting on PCR results. Negative LFT today.

So baffling.

I had the same thing a while back, lots of positive LFTs throughout my symptomatic period (of the original variety, before the new nose only ones came out) but three negative PCRs. I logged it all with the Zoe study and they sent me for an antibody test which came back negative, so in my case the PCRs were right, and the LFTs must have been picking up whatever alternative virus I had at the time. I'm rather concerned at the idea of a dodgy batch of pcr tests though, given they override the LFT result.

Bit concerning to think of the possibility of a dodgy batch of pcrs. Hope that’s not the reason for the drop in cases which is such great news.

Update- both my DS who tested positive on LFTs and then negative on PCR have had positive 2nd PCRs. I’m glad I persisted and tested them again.

It's definitely not just the SW.

There's either some dodgy PCR testing going on or, yes, a new strain that's not detected by PCR but is by LFT.

In my school we have multiple cases where, say, 10 kids get a positive LFT, all go for PCR, only 5 get a positive. All exactly the same symptoms, all sitting next to each other. Or pairs of siblings, both test positive on LFT, only one gets a positive PCR. Same symptoms. "Negative" child needs back in school infecting everyone.

Multiple classes, I mean.

People worried about negative PCRs meaning they have to send DCs back to school - every time I’ve had a test and a negative PCR the text containing the results advises to continue isolating if you still have symptoms so you can say you are following that advice.

@Badgercity I've also just received a positive result after my 2nd PCR test. DH received his yesterday. Really glad we retested.

My DH and I will get second PCRs today (tested negative on 21/9). I do worry because I work in care and they want me in unless I test positive. I’m negative on LFTs though, but I don’t want to risk a clients life on a 70% effective LFT test.

@Badgercity

Update- both my DS who tested positive on LFTs and then negative on PCR have had positive 2nd PCRs. I’m glad I persisted and tested them again.

I wonder how many won't retest and will send the children back to school.

Yep, DD1 had 3 x positive LFT but 2 x negative PCR. She had no symptoms except a sore throat.

We had 5 positive LFTs from different batches and negative PCRs each time. Luckily DH is on paternity so we isolated as he did have symptoms. I read LFTs can pick up other Viruses though but I'm not sure how accurate that is

Whinge, I know several people at our school who've done positive LFTs, negative PCRs and have been advised to go back in - what can you do? If we hadn't done a second LFT which came up positive, we'd have done the same. My DD had/has no symptoms at all. She's now testing negative on LFTs. I remain convinced she probably has had some form of covid, we probably caught the tail end of it with the positive LFTs. DH is equally convinced she never had it and the LFTs are wrong. Given that the specificity of LFTs is so high, I could believe that if we hadn't had 3 tests from 3 different batches all testing positive. It's very worrying.

We've got loads of kids in school who had positive LFTs and negative PCRs so I'm glad to hear that test centres are looking into it.

Someone one another thread kept testing positive on LFT and negative on PCR and then eventually got a positive PCR so it's not necessarily the LFTs that are wrong which is worrying.

Hang on, can we take the kids with us to the drive through test centre?

Definitely not just SW - E Midlands here and hearing of lots of people having the same.

I don't think I can't use LFT kits now because when I was using them I developed sores in my nasal tissues that have been very persistent and I'm using antiseptic/analgesic cream in my nose which I presume would mess up the results even if the presence of blood etc didn't?

The ones I have now are nostril only so presumably wouldn't work on throat?

Currently I'm just going with if I have symptoms I will do a pcr but presumably my results would be messed up on that too unless I can do that with throat only?

Thinking I can't be the only person who has nasal sores and maybe somebody else has found out what to do.

There’s nothing in the PCR or LFT instructions about not being able to use them if you’re on X, Y or Z medication though, Honey? Or is it that they were developed too quickly for them to have discovered any contraindications.

You're meant to blow your nose because even excess mucus could effect which to me suggested that blood or ointment would effect it to. I've trawled google with different searches and can't find any advice. Medications don't normally go directly in your nose.

Sorry for my derail anyway.