Negative LFT

[butterfly193]

Hi my DD had a pcr on Monday as she was due to go into hospital on Wednesday the results came back a couple hours later and they were positive 😬. Since then I have been doing LfTS which has all been negative, and now I’m starting to wonder if she even has it at all? She was due to get joint injections and now obviously she can’t have them at all 😔has anyone else experienced this?

Not with a PCR but I know that when I had it, it took about 3/4 days to show on an LFT even though I was quite ill.

It is completely to be expected.

PCRs are more sensitive - as this UKHSA blog says "We also know that lateral flow devices are effective at finding people with high viral loads who are most infectious and most likely to transmit the virus to others.". They are much less good at picking up people with lower viral loads, who would be positive on PCR (or may have been infected a while ago).
ukhsa.blog.gov.uk/2020/12/08/lateral-flow-testing-new-rapid-tests-to-detect-covid-19/

I hope she can have the procedure soon.

PCRs are more sensitive so it can take a few days ( or indeed never) to show on a LFT. A PCR will also pick it up for longer so she may have in fact had it a week or two (or longer) ago but there's no way to know now. False positives PCRs ( other than the above) are virtually unheard of.

This is interesting as the opposite happened to me. Positive lateral flow and negative pcr 🤔

I had this, though think it was a timing issue in my case as PCR was late afternoon then LFT next morning.
My DS often gets false positives on the flowflex ones though.