The number of coronavirus cases in Georgia spiked again on Saturday as more residents were tested and Gov. Brian Kemp declared a public health emergency in the state.

But questions linger over who is eligible to receive the test and who isn’t.

There are now at least 66 cases of COVID-19 in Georgia after the state saw its largest increase in a single 24-hour period, according to the latest data from the Department of Public Health. That figure was up from 42 cases on Friday and expected to increase quickly in the coming days.

But health officials have not answered questions about the number of people who have been tested in the state, and medical experts expect the actual number of cases is far greater.

“If you don’t have good testing you are releasing numbers that are really meaningless, just totally meaningless,” said Dr. Arthur Caplan, founding head of the Division of Medical Ethics at New York University’s School of Medicine.

» RELATED: Kemp declares unprecedented public health emergency in Georgia

As of Saturday morning, there were 15 confirmed cases in Cobb County, 13 in Fulton, eight in DeKalb, seven in Bartow, five in Cherokee, four in Fayette, three in Floyd, two in Coweta, two in Gordon, two in Gwinnett and one case each in Lee, Henry, Lowndes, Polk and Charlton counties, according to the latest data.

» COMPLETE COVERAGE: Coronavirus in Georgia

Cases in Bartow, Cobb and DeKalb counties doubled overnight, Kemp said at his 10 a.m. news conference.

“We have to remain vigilant, especially for our most vulnerable populations,” the governor said Saturday. “For weeks now, my team has been working around the clock to make sure that we’re ready for any scenario. We have increased capacity at our state lab to allow for coronavirus testing of specimens. Right now, we’re processing 100 specimens per day, and by the end of next week, we’ll double it to 200 per day with the addition of new equipment and staff.”

Health officials have said the coronavirus can be spread by people who aren’t exhibiting symptoms, causing concern that many will unknowingly transmit the disease to at-risk populations.

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Caplan called it unethical to announce coronavirus figures without including the caveat that so few people are actually being tested.

“Even the media should be saying these numbers basically are what is known given the limited testing we have and they are not to be trusted,” he said. “What’s going to happen is, in a week or 10 days those numbers are going to explode — we are going to see in the state of Georgia maybe tens of thousands of people all the sudden are infected ... That will freak people out to no end. But all it means is there are a whole lot of people who got infected who didn’t get sick.”

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On Friday, the Department of Public Health announced it would stop keeping an immediate tally of cases, opting instead to update its website with the latest figures each day at noon.

— AJC staff writers Greg Bluestein and Carrie Teegardin contributed to this report.