A drive-thru test site for COVID-19 on the Northwest Side will expand testing Saturday morning to the general public.

The Harwood Heights testing site, 6959 Forest Preserve Dr., will open at 7:30 a.m. to anyone 18 and older showing symptoms and anyone over 60 with underlying medical issues, regardless of symptoms, the Chicago Fire Department announced Friday.

When it opened March 23, the site was limited to first responders and health care workers. Then, it began testing people 65 and older who showed symptoms.

Starting Saturday, the site will double capacity to 500 tests daily. It’s open seven days a week.

“The site’s been very efficient,” Illinois National Guard spokesman Bradford Leighton said.

Operated by about 100 guardsmen, the site has consistently hit its limit of 250 tests per day within four to six hours, Leighton said.

On the South Side, Roseland Community Hospital opened a drive-thru test site Friday for civilians showing symptoms.

In suburban Northlake, Walmart closed a drive-thru test site that had been one of the first in Illinois. The retailer said it was consolidating resources with a Walmart test site in Joliet. That site remains open to first responders and people 65 and over with symptoms.