False negative PCR?

[Doublechocolatetiffin]

I'm just wondering if it's likely that my daughter has a false negative PCR test. My eldest woke with a temp and headache on Sunday am, we did a lft which confirmed she was positive for covid. My middle daughter was negative on the lft but later that day got a high temperature just like her sister. We ordered PCRs for them and the youngest appears to have zero symptoms but has a positive test. Eldest is positive but middle daughter still negative. She was the only one who actually let us do the PCR well! Is there any chance the tests got mixed up at the lab? I am certain I didn't mix them up, I did each pack individually and sealed it before opening the next. Or could the middle daughter have a false negative. It makes zero sense that she doesn't have it, but has another illness at precisely the same time with the same symptoms 🤔

[plixy]

Not an answer but I had similar situation.
My father in law (who I had spent time with prior to being unwell) had a positive test at Christmas. Myself and my mother in law were also both unwell and we had identical symptoms to him but we both tested negative on pcr and subsequent lfts.

[Doublechocolatetiffin]

It's strange isn't it, I'm guessing the pcr tests aren't as good as we have been led to believe.

[JanglyBeads]

PCR false negative rates are between 5 and 30%. Yes, we've been led to believe they're virtually 0.

Doctors don't trust them if a case is symptomatic and has had contact with a positive case.

[Ohsofedupwiththis]

DA got a negative PCR when he had a little cough.

Next day he had a temp and got a strong positive LFT.

Both were nasal swabs due to age. I reckon PCR was just too early.

[Toanewstart22]

I’m confused
Only one had a pcr test
It was positive
She’s not showing symptoms
That’s very very common in children

[Doyoumind]

False negatives happen but false positives are rare. Why wouldn't you believe she has asymptomatic covid?

[Toanewstart22]

* It makes zero sense that she doesn't have it, but has another illness at precisely the same time with the same symptom*

High temperature and a headache? Hardly uncommon symptoms for loads of things!!!

[TonksInPurple]

My dd had this it was just too early picked it up two days later on an lft

[germsandcoffee]

My daughters doctor didn't believe the negative pcr results as she was displaying all the covid symptoms and treated her as if she was infected.
He said they are not very reliable 🤷‍♀️

[MadeForThis]

I would isolate her, do LFTs for another day or two then book another PCR.

[altmember]

LFD tests have a moderately high chance of false negative (but not in my experience, they've been very reliable), but false positives are very unlikely. PCR tests have a lower chance of false negatives than LFD, but it's still a significant proportion. A PCR false positive is very unlikely, but it is sensitive enough to pick up a previous infection, for about 3 months after.

It sounds like your middle daughter could well have been negative when you did the LFT, but very real chance she's now caught it from older sibling. Keep doing the daily LFDs on all of you (as recommended), and even if you get a false negative on one day, chances are one of the other tests will pick it up.

Once someone brings it into the house, it's pretty unlikely the rest of the house will avoid catching it. Unless you live in a large enough house to completely avoid each other and you identify the infected person very early on so they can be isolated before infecting the rest of the household.

[Doublechocolatetiffin]

Just to clarify, we've all stayed home all week. All of us had PCR tests, of which two showed as positive. One I was expecting because she had symptoms and one who was asymptomatic. My question was in relation to the middle daughter who was showing the same symptoms as my eldest (who has covid) but just a day behind. I wondered what the chance of her having a false negative pcr test was. I could have sent her to nursery all week, the rules would have allowed it. She's under 5 so I wouldn't need to isolate her or test her daily. She is now positive on an lft so I'm glad I followed my gut and not the rules.

[Toanewstart22]

You all has pcr tests?
Sorry, this confused me

* She was the only one who actually let us do the PCR well!*

[Doublechocolatetiffin]

Yes, I meant that the others screamed and fought us during the PCR tests. I wasn't confident I'd actually done it well enough to get a proper reading but they both came back positive. The only child who let us do the PCR in a calm manner was the one who was negative. Sorry it wasn't clear. Its been a long week.