Are false negative lateral flow tests common?

[Thewholeshackshimmy]

Last week 15 year old ds came out with cold symptoms (sore throat, sneezing lots, blocked up nose, raspy sounding voice, normal temperature, no cough).
Of course the first thing that went through my mind was Covid. He did 4 LFT (Wed-Sat) all negative. So thought great, just a summer cold (he does pick up colds more frequently than the rest of us in the family).
However, since looking on the coronavirus virus section here on MN, I see that several people have had consecutive negative LFT but test positive with a PCR, now I am a bit worried.
He went back to school yesterday but still has a blocked nose and raspy sounding throat, no temperature or cough though and says he feels ok.
I am worrying now that it still could be Covid.
I think I’m going to have to pop him down to our PCR test centre but will they do one if he has no temperature, cough or loss of smell/taste?
Is it common to test negative on several LFT yet still actually have Covid?
I have also done LFT on myself and 13 year old dd (she also had one at school yesterday) and we are negative too.
All test have been the newer, nose only tests.

Yes, apparently so.

"When it comes to LFTs, the accuracy appears to depend on the make of the test used, whether people have symptoms, and who is conducting the test.

For example, one study by researchers at the University of Oxford and Public Health England’s Porton Down lab found the LFTs were more accurate in the hands of skilled scientists, picking up 79% of Covid cases, than self-trained members of the public, who detected 58% of Covid cases.

Estimates for these rates vary. However, according to the Department of Health and Social Care (DHSC), and comparing results against those obtained by PCR testing, the false positive rate for LFTs is fewer than one in 1,000, while the false negative rate could be as high as 50%."

From the Guardian.

Very common if you have symptoms. They should not be used if you have any symptoms at all.

I’ll have to get him a PCR test, I won’t rest until then.

I was pinged, did LFTs for. Solid seven days, all negative, and the pcr on the eighth day was positive. I trust the lateral flows about as far as I could lob the person who rubber stamped their use.

I had a negative LFT followed by positive PCR the next day. I was asymptomatic but tested because one of the DC was positive. They are not very accurate but will pick up some positives so better then nothing. DC was very strongly positive on the LFT.

I read in the news that once you have symptoms it is too late for a lateral flow test and you need a PCR. IT is something to do with the different things each of them test for.

I’ve known LFT be positive when a PCR is negative and vice versa on so many occasions, that I don’t trust them at all. I do still use them as I think it’s better to do so than not, but why sign it symptoms and it’s a PCR you need anyway.

All of my children tested positive on LFTs and PCRs. They tested when the symptoms started. One of my dds did several LFTs and only one was positive. But she still had a positive PCR test. I think I read it's more possible to have a false negative LFT than a false positive one.

I've not tested positive on either.

@RuthW

Very common if you have symptoms. They should not be used if you have any symptoms at all.

I know they're not supposed to be used with symptoms but I don't know why? Why woukdn having symptoms make them less effective?

I thought it was because with symptoms you need a more reliable test not because the symptoms make the LFT more unreliable?

@LadyDanburysHat

I read in the news that once you have symptoms it is too late for a lateral flow test and you need a PCR. IT is something to do with the different things each of them test for.

LFT are actually more reliable if you have symptoms than if you don't although still have a high false negative rate

They aren't accurate enough to say you don't have covid if you do have symptoms which is why PCR should be used instead

You can’t use them with symptoms as they only pick up 4/10 cases of covid. So helpful as a weekly screen to the symptomless where we might pick up a few extra cases.

But pointless If symptoms as you might well have covid and 6/10 it won’t spot it.

I had negative lateral flow on the same day had positive pcr. I tested because dh had cold symptoms and tested positive on lateral flow.

We're all ill with a bug. It's hit me the hardest, still in bed a week after symptoms began.
4 negative pcr tests. Have just booked a pcr one for 5pm after reading this thread.

I thought you were only supposed to use those instant tests if you had no symptoms. And if you have any contact concerns or have symptoms you get an nhs test.

The instant tests are rubbish. Prob why you need an nhs one to properly rule out covid.

A family member tested negative for three consecutive days (before, day of, and after her nhs test).

The nhs test was positive. All three she did at home were negative.

Shows you how shite they actually are.

Yes, I did loads of LFTs on both myself and DS, all negative. Both of us tested positive on PCRs.

For everyone saying that lfts shouldn't be used if you have symptoms, the problem is the OPS DS doesn't actually have a symptom that qualifies for a PCR test.

DH had covid a few weeks ago. Picked up on a PCR. He had done several LFT's in the days before the PCR - all negative. He even did a LFT after he got the email confirming the positive PCR - LFT still negative. He had no symptoms at that point and went on to develop mild flu symptoms a few days later.

Do they ask what symptoms you have at the PCR testing centre?
If so I will have to lie as ds has no cough, high temperature or loss of taste/smell.

@Thewholeshackshimmy

Do they ask what symptoms you have at the PCR testing centre? If so I will have to lie as ds has no cough, high temperature or loss of taste/smell.

No. I had no symptoms when I went for a PCR, I went because I'd been a close contact of a positive case. No one asked anything.

No, no one asks about what symptoms you may or may not have.

Dd had a positive lateral flow. The PCR the same day was negative (I'm a nurse and done lots of tests - so was very thorough with the swabbing despite dds gagging... )

Subsequent lft's are negative.

I’m taking him for a PCR today just incase as I have a hospital procedure booked on Monday which I’ve waited a year for, just hope it’s negative 🤞

No symptoms - LFT
Symptoms- PCR

LFTs wont usually give a positive result while the actual result is negative but have given negative results when the actual result is positive ( which is more dangerous than the first mistake?)

PCR is more reliable as its done in a lab. People with symptoms might want to take a lab test as LFT could show negative even though the virus is present.
My friends daughter had 4 negatives in LFT but took a PCR anyway because it was a weekend and they could go to a centre. The test came out positive. Unintentionally, the daughter has been going to school keeping LFT results in mind.

The govt website also says LFTs are fine with symptom less people but people with symptoms need to take PCR.