Covid tests: how can people be positive on lateral flow and negative on PCRs?

Reports of conflicting results are common if mystifying; however, scientists have a number of explanations

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Lateral flow tests (LFTs) are an increasing part of our everyday lives. But for some individuals, a persistent clash with their PCR test results is undermining their confidence in the system.

The Guardian has been contacted by hundreds of people who have repeatedly tested positive on lateral flow devices (LFDs), but whose confirmatory PCR tests have been relentlessly negative.