They posted this figure to justify it.
Let's work through the math!
translate.google.com/translate?sl=a…
#1 If you test a town with 12,250 people, 1 is a true positive (has COVID19 and is also PCR positive)
#2 For every true positive you will get 12.5 false positives(!)
#3 Probability of a positive response being true is 7.4%
There are 12,248.8 COVID19 negative people and 12,236.3 of them have a negative PCR.
12,236.3/12,248.8=99.9%
Specificity is 99.9%
It's hard work to find needles in haystacks!
On your own, work through the same exercise for any of the other columns. See if you get the same numbers!