The state had 211,660 COVID-19 cases—an increase of 1,753 from the previous day and 38 newly reported deaths, bringing the number of statewide virus-related deaths to 5,409 on Sept. 17 according to data from the Arizona Department of Health Services. The number of new cases reported Sept. 17 represents the highest number of cases reported in a day since July 31. The Arizona Department of Health Services tweeted Sept. 17 that a significant increase in test results from Arizona State University was partially involved in the increase.
Of 20,133 diagnostic tests—which include polymerase chain reaction, known as PCR, tests and antigen tests— in Maricopa County reported on Sept. 17, 1.64%, or 331 tests, came back positive for coronavirus. The PCR test determines an active case of COVID-19, the other kind of testing data the state tracks is related to serology—or antibody—tests, which determines if a person has been infected in the past with the virus. Antigen tests "may not be as accurate or able to run as many patient samples per day, however, the quick results provide the ability to rapidly triage and make decisions," according to ADHS. The county also reported 30 new deaths Sept. 17, bringing the county's death toll to 3,199, according to data from the Maricopa County Department of Public Health.
Of the county's 3,199 known deaths, 1,091 are tied to long-term care facilities, making up 34.04% of the county's total COVID-19-related deaths.
The state and county also track hospitalization data. In Maricopa County, 10% of the county's total cases resulted in hospitalization as of Sept. 16. The county tracks intensive care unit, or ICU, data separately. One percent of the county's total cases have resulted in admittance to the ICU. Statewide, as of Sept. 17, ADHS reported 10% of the state's cases have resulted in hospitalization—23,844 cases across the state.
According to data from the state, of the completed and reported Maricopa County COVID-19 PCR tests, 13% of them have yielded a positive result.
Statewide, there have been 1,350,116 diagnostic tests completed. Of the total PCR tests across the state, 11.7% have yielded a positive result.