Negative Lateral flows but PCR positive

[Bauble1234]

Someone I know had a close contact who tested positive for Coronavirus. He kept doing lateral flows which were all negative but did a PCR (as a precautionary measure) which tested positive. Is it because Lateral Flow tests are no good ie not accurate enough?

I never tested positive on lateral flow but did on pcr. I continued to try with lateral flows every day and still didn't ever test positive

They aren't as sensitive as PCR so need a higher viral load to show positive. Theres a graph explaining it on other threads, I'll see if I can find it.

It's in this article
www.ft.com/content/cbd0fb0a-8c41-4b9b-aa4c-0afa10619383

Yes, the PCR tests are more reliable. Done in a lab. He is positive. Same happened to me

See diagram.

Yeah the LFTS aren't as good. Which is a shame as not everyone is going to get a PCR just in case as it's a waste of PCRs but at the same time is it? Because it picked up your friends case.

PCR can detect at lower viral loads. I've also recently heard the omicron variant can evade lateral flows 🤷🏻‍♀️

Some people might not get infectious enough for a lateral flow to ever pick it up. But lateral flows are cheaper and faster, so there’s the trade off. They’ll pick up the “worst” cases.

I had the same. 4 negative LFTs before having a positive PCR. My illness was very light so I guess I was not infectious enough for the LFT

@Bauble1234

Someone I know had a close contact who tested positive for Coronavirus. He kept doing lateral flows which were all negative but did a PCR (as a precautionary measure) which tested positive. Is it because Lateral Flow tests are no good ie not accurate enough?

As a close contact, he should have just gone straight for a PCR test (even without any symptoms himself) rather than keep doing the LFD tests. T&T should have clearly stated that to him!

There's calls for LFD testing for symptoms if we keep running our of PCR capacity.
I feel like this is a problem for that idea.

@Meredusoleil

T&T don't advise a PCR for close contacts if they are double jabbed, the direction given is to do LFT's for 7 consecutive days

We've had 7 out of 7 adults who mixed across 2 family groups at Christmas test positive (well 6 but the 7th has all the symptoms and waiting on pcr result). All had had several days of negative lateral flows when they met up. I'm gutted at how inaccurate the lft turned out to be, and angry that there was nothing else we could have done to ensure safety before we met but someone was positive.

[quote AlwaysWaiting78]@Meredusoleil

T&T don't advise a PCR for close contacts if they are double jabbed, the direction given is to do LFT's for 7 consecutive days[/quote]
My mistake. I forgot the guidance changed quite recently!

I’m not sure this is at all relevant but 4 people all from my work, 3 without symptoms and one only with a slightly raised temp, all tested positive on laterals, all been diagnosed with omicron.... they must somewhat work. No one else at work has had symptoms and all are testing daily and no more since Tuesday now.

Lateral flows are useless. I’ve had symptoms for days (although could be a cold) and I’ve taken the lateral flow every day for 4 days, I’ve just had one positive. Luckily I’ve been avoiding going out. Can’t get hold of a PCR for life nor money.

@Yamaya

I never tested positive on lateral flow but did on pcr. I continued to try with lateral flows every day and still didn't ever test positive

I know several people where this happened

As for me I am fairly sure I got covid very mildly (dh and ds had it), lateral flows all negative, one pcr was negative but in hindsight it was a bit too early.

I know someone who tested positive on a PCR recently (main symptom a dreadful sore throat) but remained negative on LFT. She never had a positive LFT!

I do the Zoe app, and it sent me for a PCR based on symptoms I had. They were not symptoms indicating you should go for a PCR normally. I had negative LFD tests throughout. I wasn't particularly poorly.
At first I doubted the LFD test, but then thought maybe it's right - I was only mildly poorly, so perhaps I had a low viral load so it didn't register on the LFD.
I was curious about whether I really had had covid, so I paid for an antibody test which specifically looks for antibodies as a result of infection (as opposed to from the vaccine). No such antibodies were detected.
So, it suggests my PCR result was a false positive, and the LFD results have been correct.

@Yamaya

I never tested positive on lateral flow but did on pcr. I continued to try with lateral flows every day and still didn't ever test positive

Same for my DS, never once tested positive on a lateral or showed any symptoms whatsoever yet had a positive PCR phe came into school to pcr the whole school after a breakout none of us went on to catch it. I'm convinced it was a false positive.

My LFTs are still showing positive for Covid. I'm testing for the 6 and 7th days to get back to work. I can't see an end tbh

@rivermum

I do the Zoe app, and it sent me for a PCR based on symptoms I had. They were not symptoms indicating you should go for a PCR normally. I had negative LFD tests throughout. I wasn't particularly poorly. At first I doubted the LFD test, but then thought maybe it's right - I was only mildly poorly, so perhaps I had a low viral load so it didn't register on the LFD. I was curious about whether I really had had covid, so I paid for an antibody test which specifically looks for antibodies as a result of infection (as opposed to from the vaccine). No such antibodies were detected. So, it suggests my PCR result was a false positive, and the LFD results have been correct.

Does everyone develop antibodies after covid? That’s also an option!

Here is a chart explaining.

An LFT positive is extremely reliable.
An LFT negative is not, especially if you have any symptoms, including cold symptoms.

The PCR test measures tiny amounts of virus. LFTs measure whether there’s detectable replicating virus, i.e. whether you’re likely to have enough virus in your nose/throat to be infectious.

There’s no direct relationship between how much virus you have in your body, and symptoms. I have an overactive innate immune system and routinely get flu-like symptoms with diseases I don’t catch. For example, both my little boys got chicken pox in September and I spiked a 38.5 degree C fever the day before they came out in spots, and then had itching/joint pain/fever until the spots crusted over.

I haven’t bothered doing a PCR as we’re all self-isolating, but my DH tested positive on Xmas Day by LFT/PCR - having begun symptoms on Xmas Eve. Since the afternoon of Xmas Eve, I’ve had (variously) a sinus headache, violent sneezing, a fever over 38 degrees C, dry eyes, blocked tear ducts, multiple mouth ulcers, tickly throat, a ‘scorched’ feeling in my windpipe, chest pain, a dry cough, dry mouth, bouts of itching on my arms/waist/ankles, stiff wrists/toes, and nausea. The symptoms get worse if I’m in a poorly-ventilated room with my DH for more than an hour, and get better if I’m stood outside in the open air.

At no point have I tested positive on a LFT - and I’ve been taking them daily as a close contact of a household case. Thus, all those symptoms were caused by my innate immune system reacting to airborne virus - rather like allergies - and not to my viral load.

Hope that clarifies… And, yeah, it is weird.

They can be accurate fir some people but not others. They can't be relied on. For me and dp they showed up positive before symptoms started. Dp had been a close contact and I caught it off dp. I started to get symptoms one day after positive lft.