Positive lateral flow test negative pcr test

[potterface29]

I'm so confused! Took my first ever lateral flow on Saturday, as my daughter who's at nursery, came back positive. Im 32 weeks pregnant so this terrified me, took another that also came back positive! Booked a PCR test for the whole family, which took until Sunday evening to come back, negative for me and my husband and daughter. However can still get a positive result on a lateral flow. Called nhs 119 and they just advised me not to take the rapid test anymore! But couldn't tell me why I was getting positive results on rapid test?

Mostly worried about the baby and pre term labour , but also don't want to spread the virus unknowingly. I'm very careful being pregnant and don't really go anywhere other than supermarket at the dead of night.

Anyone else in a similar boat? Anyone had Covid late in pregnancy like third trimester?

Thank you
Many thanks

@notrub I believe it's in the guidance to schools. We were told not to take an LFT if we've tested positive in the past 90 days as we'd test positive as a result of previous infections

I believe it's in the guidance to schools. We were told not to take an LFT if we've tested positive in the past 90 days as we'd test positive as a result of previous infections

It's probably because nobody has ever been reinfected within such a short timeframe.

LF's require quite a high viral load in order to register a +ve, which is why they are only about 40-50% effective at picking up cases. There were at one stage a few people arguing that PCR's would show a +ve result for old infections like this, but even that was never proven.

But given the volume of tests they're undertaking, the specificity becomes a problem - even at 99.9% that's still one false +ve per thousand. If they can exclude certain groups who could NOT possibly be infected, then it reduces the impact of these false +ve's on the school.