- 23 Jan 2018
I've answered this before: they are either running their PCR testing with a much higher 'threshold',
or are exclusively using Lateral Flow (rapid) tests, which don't have the false positive issue as their
threshold is far higher than PCR testing in the first place.
The UK is currently transitioning from PCR to lateral flow (ratio is currently around 50/50),
so if that trend continues in the coming weeks in combination with falling prevalence in general,
false positives will eventually become background noise, just as they were last Summer.
In other words, if we can get to the point where (say) 80% of tests being conducted each day are lateral flow,
it could be feasible to get below the 'magic' 1000 positive tests per day figure by Easter.
Just to clarify - do you mean lower thresholds? (unless you're talking about virus particles being present?)
Also I just looked up the estimated FPR of LFTs and it comes up with "the overall false positive rate was 0.32%, although this was lowered to 0.06% in a lab setting." (https://www.ox.ac.uk/news/2020-11-1...eral-flow-tests-show-high-specificity-and-are)
The articles say the government want to do 10m tests per day. Even with the lab setting FPR (which isn't going to be the case), that would be 6,000 false positives a day potentially.