SIMI VALLEY (CBSLA) — Ventura County has four drive-thru coronavirus testing facilities up and running, but not everyone who wants to be tested can be served because of an ongoing lack of tests.

One of the drive-thru testing sites is at the Family Medical Clinic in Simi Valley. It’s one of four now serving patients, and the county says they hope to have a total of seven operating at urgent care clinics by the end of the week.

However, even with more testing sites, a shortage of tests has placed stringent requirements on who can be tested. Ventura County public health officials are asking the public to help them save testing supplies for those who are high risk, vulnerable and have symptoms.

“We don’t have enough swabs to test everybody who comes through the drive-thru, so those who have been exposed, have a travel history, a fever, respiratory symptoms like cough or shortness of breath, those are the patients that really need to get the testing,” Ventura County County Medical Center’s Dr. Theresa Cho said.

Patients who do get permission from their doctors to get tested simply pull into a parking space, undergo an evaluation by a nurse while in their cars, and if necessary, they will decide at that time to administer the test.

Orange County also has a drive-thru testing site at St. Jude Heritage Medical Group in Yorba Linda.

The White House has promised to deliver 1.9 million tests by the end of the week. Gov. Gavin Newsom says California will be running 8,000 tests a day in about a week, with the help of local labs.

But because of the ongoing lack of tests, patients with fever and cough or shortness of breath will only be tested if they have been hospitalized with severe lower respiratory illness, are a healthcare worker, working in a public safety occupation, are older than 60 years, has an underlying medical condition, or pregnant.