Test positivity can be calculated in two ways: as the percentage of all COVID-19 tests that come back positive, or, the percentage of people tested for active infection that return a positive result. For example, Iowa’s test-positivity rate of 37.2% between Oct. 26 and Nov. 9 implies that for every 100 people tested for COVID-19, 37 are positive.
Test positivity tells public health officials whether a testing program is casting a wide enough net to catch the majority of COVID-19 cases.
