(Des Moines) The Iowa Department of Public Health (IDPH) is now reporting positive and negative antigen test results following a steadily increasing volume of the rapid-result tests across the state.
Iowa Public Health Director Caitlin Pedati says Antigen testing is a new type of COVID-19 diagnostic test that detects proteins on the surface of the virus and generates results faster than a PCR test, which sees the virus’s genetic material. She says PCR tests are considered the “gold standard” for clinical diagnosis of COVID-19 and is the test used by the State Hygienic Lab and Test Iowa.
Pedati says the Department of Public Health has received approximately 10,000 of these antigen tests, and those about 1,000 have tested positive.
While some states have chosen not to report antigen results, IDPH believes doing so will provide more complete information for Iowans. Updated data on coronavirus.iowa.gov now includes case counts for both PCR and antigen tests separately and the combined total test results.
According to the CDC, the sensitivity of rapid antigen tests is generally lower than PCR tests, and clinical performance depends on the circumstances in which they are used. Antigen tests can be helpful for individuals tested in the early stages of infection when viral load is generally highest, or for known exposures to a confirmed case of COVID-19. They are also effective in high-risk congregate settings in which repeat testing could quickly identify positive patients to inform infection prevention and control measures and prevent further transmission.
Currently, in Iowa, antigen testing is being used in long-term care facilities, health care clinics, retail pharmacies, and a variety of other testing providers.
Antigen testing accounts for just 1.8% of all COVID-19 tests in Iowa at this time, but the use of the test is increasing and expected to continue.
To date, antigen tests have been included in Iowa’s total case count, but individual test results have been classified as “inconclusive” rather than as positive or negative cases. Now that more is known about antigen tests, negative and positive results are now included in the state’s COVID-19 case reporting and calculation of positivity. The inclusion of antigen tests results in minimal change to the state’s positivity rate.
