PCR false negative

[Uramaki]

Is there such a thing as a false negative result on a PCR test?

Yep. Up to 30% false negatives ….

Bmj :
Sensitivity of PCR testing in the real world (taking into consideration the likelihood of the virus getting onto the swab) is only of the order of 70%. It misses (gives false negative results) in about 30% of people who do actually have the virus, and who may be contagious.

Oh great.. that explains a lot right now. Do you think if someone took 3 tests and one came back positive they should go with that? Am considering doing another 2.

But seems like a waste of funds. But the circumstances I am in are too coincidental for it not to be covid.

If one came back as positive then you go with it, no matter how many negatives you then get.

Ok, do you think if I explain it to them on the phone they'll send me more. It's highly unlikely the cough is not covid as everyone around them has had covid.

I know someone who had a false neg pcr. One two days later was positive. They had symptoms for both.

If they’re sending them to you aren’t they LFT?

You're not supposed to use lateral flow tests if you have symptoms. You can order a PCR test online which will come in the post and you post it back, or book a drive through test

@CovidCorvid

If they’re sending them to you aren’t they LFT?

No the postal ones. We already did one postal PCR Negative. But it's too much of a coincidence not to be covid so I don't trust it so I might ask for 2 more ? You need the positive test to put the code in the app.

@CovidCorvid

I know someone who had a false neg pcr. One two days later was positive. They had symptoms for both.

This is what I'm worried about.

Just ask for another, I doubt they’ll question it. My friend certainly could make subsequent appointments days apart.

It might not be a false negative. There’s a reason for a ten day isolation period - it may take that long for covid to multiply enough and take hold. So if you took an early test, it could be negative because there isn’t enough virus? I don’t know 🤷🏻‍♀️

Either way, just order another test if you’re genuinely concerned.

My son's football coach felt poorly on a Thursday, went for a test Thursday evening and it came back negative. He went for another test on the Saturday to be certain because he had all of the symptoms and it came back positive.

So I do think it's possible.

I was wondering this, my sons friend had 2 positive Laterel flow tests - see image of his test result below so had a PCR test which was negative, he was with myself and my son on the day before he carried out his Lateral flow tests (he did 2 to be sure) and we were told only have to isolate if the PCR is positive, well it was negative but now both myself and my son have headaches, sore throats and runny noses, we will get tested but I thought PCR negatives were really low and it was the lateral flow ones that gave false readings. Incidentally my sons friend had no symptoms and only did the lateral flow for his work.

Thanks everyone, I've ordered another one

@Helenluvsrob

Yep. Up to 30% false negatives ….

Bmj :
Sensitivity of PCR testing in the real world (taking into consideration the likelihood of the virus getting onto the swab) is only of the order of 70%. It misses (gives false negative results) in about 30% of people who do actually have the virus, and who may be contagious.

Isn't that LFTs? PCR tests are significantly more accurate.

Apologies, it seems PCRs can indeed give 30% false negatives according to BMJ article.

@Warhertisuff

Apologies, it seems PCRs can indeed give 30% false negatives according to BMJ article.

I didn't expect them to have such a high rate given that they are used to decide who isolates.