Maricopa County public health officials are changing the way they count COVID-19 cases.

As of last week, the county’s daily reports of new cases only included positive results from PCR tests, short for polymerase chain reaction.

As of Friday, the county added 682 positive results from antigen tests, which offer rapid results that, according to the Centers for Disease Control and Prevention, aren’t considered as reliable.

Kathy Ritchie/KJZZ

Dr. Rebecca Sunenshine

Dr. Rebecca Sunenshine, the county’s medical director for disease control, said positive results from antigen tests are considered “presumed positives,” and adding the results to the county’s coronavirus tracking data will provide a more complete picture of the spread of the virus.

That doesn’t mean trends in how the virus is spreading have changed.

“It means that we've had 628 positive antigen tests since the beginning of the pandemic. And those are scattered throughout several months. So they actually represent less than one half of 1% of all the cases there are,” Sunenshine said.

Sunenshine said the new data changed nothing about the virus’ peak in late June and the decline since then.

“But as these tests become more widely used and widely available, they may have more of an impact,” she said.

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