Worth noting that this represents 607,559 COVID-19 tests with 226 positives, giving a positive rate of 0.0372%
Even if EVERY TEST was a false positive, that gives a specificity of ~99.96%
Even if EVERY TEST was a false positive, that gives a specificity of ~99.96%
https://twitter.com/GidMK/status/1319084436630073344
But, because positive people are almost always retested here we can actually examine this question more robustly. Of the 226 positive results, one was later retested and found to be a false positive! 
To calculate test specificity, we take TN/(TN+FP) = 607333/(607333+1) = 99.99984%
To put it another way, very roughly 1 false positive test per million tests done
To put it another way, very roughly 1 false positive test per million tests done
This very quickly and easily shows why the idea that most COVID-19 positive tests are false positives is simply misinformation and mathematically impossible
If 1%, or even 0.1%, of all tests done were false positives, we would expect to have seen 1,000s of positive COVID-19 results in NSW in the last month rather than a few hundred
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