Has anyone had 2 or more negative PCR’s and then a positive?

[Littlemiss74]

Dh & ds tested positive at the weekend with pcr’s. I went for one, had no symptoms & it came back negative. Later that day I felt unwell but with nausea not the 3 stated covid symptoms. So the.next evening I had another pcr, negative again. I’ve done lateral flows every day since Sunday, all showing positive. I don’t feel especially unwell, a bit tired maybe. Is it possible it can take several days for a pcr to show as positive even if lateral flows are?
Anyone with a similar experience?

If the PCR test is taken within 2 days of the positive lateral flow test, and is negative, it overrides the self-test LFD test and the pupil can return to school, as long as the individual doesn’t have COVID-19 symptoms.

Interestingly, this is in the COVID schools guidance. It is essentially saying that a positive LF plus symptoms means you should isolate. I’d say it’s a lesser know route to a positive diagnosis?