AZDHS Seems to be Miscalculating Positive Test Rates
The total number of cases in AZ is 148,683. We have had 1,019,120 total tests, of which 807,666 were PCR tests, and 211,454 were serology tests. How is it possible that the total positive rate is being reported as 12.4%? I would imagine that 14.6% is the correct figure. If it were 12.4%, then either the figures are missing significant amounts of negative tests, or are over-counting cases by about 20,000.
Similarly, the PCR test rates are reported as 14.6%, which seems to be assuming that all tests are PCR tests. If the positive test rate is 14.6% of 807,666 tests, then that would mean 117,919 positive results. If the Serology positive rate is 4.4% of 211,454 tests, then that would mean a further 9,304 positive results. Combined, that is only 127,223 positive cases. Where are the other 21,000?
What is going on here? The same footnote applied to all three statistics doesn't clarify much.