Positive antigen test result reporting behind massive spike in new Arizona cases

A highly magnified, digitally colorized transmission electron microscopic (TEM) image showing a coronavirus (National Institute of Allergy and Infectious Diseases (NIAID))

On Sept. 17, Arizona saw a major jump in COVID-19 cases, with more than Coronavirus cases in arizona seeing a major jump today, with 1,753 new cases and 38 new deaths reported.

Despite the seemingly big numbers, it doesn't mean the outbreak is worsening, as the jump has do with how the Arizona Department of Health Services is reporting cases.

AZDHS is now including positive antigen tests in the total number of positive cases. Officials with the department say about 500 to 600 of the cases added on Sept. 17 were the result of adding in those results.

What is an antigen test?

The antigen test, not to be confused with an antibody test, is a rapid way to determine current positive COVID-19 infections.

“It’s very similar to when you take your child to the pediatrician and you get that strep test and you can get that rapid result. We now are including those as presumptive positive in our results," said AZDHS Director Dr. Cara Christ.

The test has shown to be almost as accurate as other tests that have to be sent to labs. Antigen tests can be read on-site.

“The university of Arizona is using it to get quick results for their students, as they’re moving into dorms and getting ready for sports,” said Dr. Christ.

The implications of an accurate rapid test could be far-reaching. Former state health director Will Humble says the tests could help better control the pandemic.

"From looking at a population perspective, in terms of controlling this epidemic, that immediate information is super valuable," said Humble.

The PAC-12 and other sports conferences are hoping to use the lower cost tests on athletes to get sports back up and running. Humble says you can apply that same scenario to other parts of life.

“It’s great for assisted living or skilled nursing, because you’d be able to test a staff person when they come into work," said Humble. "Even if they’d been out clubbing, you can test them. Wouldn’t have to send it out, and you can say sit in the chair before you start your shift."