The state had 442,671 COVID-19 cases—an increase of 7,635 from the previous day, and 142 newly reported deaths, bringing the number of statewide virus-related deaths to 7,819 on Dec. 18, according to data from the Arizona Department of Health Services.
The number of diagnostic tests reported in Maricopa County as of Dec. 18 was 11,810 with 19.31%—or 2,280 tests–coming back positive. Those tests include polymerase chain reaction, known as PCR, tests and antigen tests. 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 47 new deaths Dec. 18, bringing the county's death toll to 4,609, according to data from the Maricopa County Department of Public Health.
Of the county's 4,609 known deaths, 1,466 are tied to long-term care facilities, making up 31.89% of the county's total COVID-19-related deaths.
The state and county also track hospitalization data. In Maricopa County, 7% of the county's total cases resulted in hospitalization as of Dec. 18. The county tracks intensive care unit, or ICU, data separately, and 1% of the county's total cases have resulted in admittance to the ICU. Statewide, as of Dec. 18, ADHS reported 7% of the state's cases have resulted in hospitalization—32,293 cases across the state.
According to data from the state, of the completed and reported Maricopa County COVID-19 diagnostic tests, 12.5% of them have yielded a positive result.
Statewide, there have been 2,605,792 diagnostic tests completed. Of the total PCR tests across the state, 11.9% have yielded a positive result.