False positive on lateral flow?

[BrutusMcDogface]

What are the chances?! A quick google hasn’t really given me any anecdotal evidence. It’s my child, not me. Booked pcr for tomorrow.

I had a faint positive Lft Sunday. Subsequent lfts have been dark as control line immediately. Waiting on pcr result should be today. Different brands of LFT so if it comes back negative something weird is going on
DD (4) had same faint line on Monday, subsequent tests all negative. So I suspect hers was a false positive. Waiting on her pcr too

@Bayleaf25

People say it’s rare but I’m another one, positive LFT and negative PCR. DH only had PCR because of my positive LFT and his PCR was positive 🤷‍♀️.

This was very recently too.

Seems extremely likely that you had a false negative PCR.

@elelel

I have seen this graphic before, not sure of the source?

It's from a mathematician mobile.twitter.com/kit_yates_maths/status/1447108816328343552 Tbh the source doesn't matter because the maths is sound, it's just a useful illustration.

It doesn't allow for the fact that some people get repeated LFT positives, or for children forgetting that they've just drunk a glass of orange juice (presumably not a problem any more with nasal tests), but the principle is sound. When you have other factors suggesting that you have Covid, such as characteristic symptoms or a very close contact who's tested positive then the odds are even higher that a positive LFT is correct regardless of PCR.

When you have other factors suggesting that you have Covid, such as characteristic symptoms or a very close contact who's tested positive then the odds are even higher that a positive LFT is correct regardless of PCR.

Yes, I was going to say something similar. You can't look at these test result in isolation. The prior probability that you have Covid based on the overall infection rate, your contact with people with Covid, and the presence of symptoms all make a significant difference!