You’ll need the estimated prevalence rate to work out the false positives … see previous posts on how to calculate this.
Prevalence rate below link from June 26th … 1 in 260 … approx. 0.4%
https://www.reuters.com/world/uk/english-covid-19-prevalence-rises-1-260-ons-says-2021-07-02/
The Shadows 