As the tally of COVID-19 cases in South Carolina grew exponentially, doubling roughly every three days throughout the last three weeks of March, Gov. Henry McMaster consistently said he relied on data to help determine what steps to take. In incremental moves, he shuttered various businesses and activities and eventually issued a stay-at-home order that took effect April 7.

But throughout that time, the state tested far fewer of its residents for the deadly novel coronavirus than nearly every state in the nation, and that deprived state and local officials of important data to help drive decisions.

Coronavirus updates in SC:Here's what you need to know

While neighboring Southern states crimped residents’ movements in an effort to slow the spread of the virus, McMaster more slowly reined in the Palmetto State. And as public health officials pleaded with South Carolinians to clear the parks and beaches, worship from home, and limit congregating, the one marker that could best prepare medical personnel, first-responders and county emergency managers to the impending crisis remained elusive — an accurate accounting of the number of COVID-19 cases in various locations in the state.

Finally, after public outcry, McMaster ordered the state Department of Health and Environmental Control to issue more details about the pandemic, including an estimate of the true number of cases in the state, not just the ones confirmed through testing.

That estimate, released for the first time late April 6, showed there were likely 15,341 people infected, while the number of confirmed cases stood at 2,232. By Wednesday, that estimate had grown by more than 2,600 to 17,964 while confirmed cases rose to 2,552.

The governor's office did not have access to those estimates — identified by ZIP code in DHEC's accounting — before the public did on April 6, said DHEC spokesperson Laura Renwick.

Asked about McMaster's access to data before April 6, McMaster spokesperson Brian Symmes wrote in an email, "The governor is extremely confident that the team at DHEC has provided him with all information necessary for making the many difficult decisions he’s made throughout this crisis.”

SC coronavirus map:A look at COVID-19 cases by county and zip code

In the critical early days of the virus' local spread, when officials sought to investigate individuals and trace their contacts in the interest of containment, the state was among the slowest in the nation to react with widespread testing, according to a nationwide analysis of tests conducted by April 3 by USA TODAY.

As of April 3, when 41 states had issued stay-at-home orders and South Carolina hadn’t, the state had conducted 136 tests per 100,000 residents, which ranked 48th in per capita tests, trailed only by California and Oklahoma according to the COVID Tracking Project, a journalist-built resource that’s tracked state-level data across the country.

The number of confirmed cases are likely a vast undercount, because early on in the crisis, DHEC severely limited who could get approved for a test. The state health agency lacked enough testing kits and at times lacked chemical reagents to analyze the tests it had conducted. Further, many who contracted the virus have had few or no symptoms and don’t require medical care, so they might not have suspected they were infected or sought to be tested.

Yet, even as the testing lagged and McMaster took a measured approach, he stressed that he had the information he needed.

“We’re trying to do everything we can to keep businesses flourishing and keep businesses going without putting public health in jeopardy,” McMaster said March 26. “That is the reason why we listen to and count on the expertise, analysis, science, data and facts and the professionals who make these kinds of understandings and recommendations for a living.”

Kathleen Cartmell, an epidemiologist and former researcher at the Medical University of South Carolina who is now a health sciences professor at Clemson University, said access to accurate and timely data early on in an epidemic is critical to limiting its spread.

South Carolina did not have accurate or timely data, unfortunately, because it didn't have access to testing supplies quickly enough and couldn't get test results back quickly enough to make a difference, Cartmell said.

"I was so surprised both nationally and in South Carolina how early on we had such a limitation on the availability of test kits and the availability of the reagents to do the testing and the staff to be able to do the tests," Cartmell said. "I was really disappointed that we didn't have more of a national plan."

She called it critical to run tests even before the virus arrives so you know when it does arrive and can quickly isolate those affected, trace their contacts and hopefully limit the virus' spread so everything doesn't have to shut down.

But even once it's spread, more widespread testing can help public health officials locate clusters of cases, isolate hot spots, predict when a surge of cases might impact the health systems and allow the public to know when it's safe to return to normal, she said.

Sick people from Myrtle Beach to Taylors struggle to get tested

Even as South Carolina’s cases increased and officials used ever-stronger language to urge residents to socially distance themselves, the state health department announced it would shift its resources from trying to contain the disease within pockets to a strategy of mitigating how widespread it will be.

That’s where the state is now, and that has changed the testing strategy.

“In the mitigation phase, testing strategies focus more on testing a reasonable sample of those who are ill in a community rather than attempting to test and identify every single case,” said Dr. Linda Bell, state epidemiologist with DHEC.

The state would now prioritize investigations of those at higher risk of exposure or severe illness, Bell said at a briefing March 26.

But even some who have symptoms, live with elderly or healthcare workers and have underlying conditions have had trouble obtaining tests, even within the last week.

Take Cameron Ventura. He’s 28, works from home and has a 15-month-old daughter, a history of asthma and a wife who works as a trauma physician’s assistant at the local hospital in Horry County. He knew to be vigilant and hadn’t left his home in more than two weeks when he began to experience respiratory tightness, shortness of breath, a sore throat and headaches March 24-25.

“About day four or five, I decided to go in and try to get checked, especially with my wife in health care,” Ventura said. “If she gave it to me, I didn’t want her to have to go back and potentially infect other people and patients.”

He went into the hospital’s emergency room. They asked for his symptoms, checked his oxygen levels and took a chest X-ray, which came back clean. The doctor agreed it wasn’t asthma but didn’t know what it was and said Ventura didn’t qualify for a COVID-19 test because his symptoms weren’t bad enough to check into the hospital, Ventura said.

“They wanted me to self-isolate,” he said.

His symptoms worsened at home. He developed chest pain and fatigue, so he returned to the hospital.

Again, he was told they could provide testing only to patients who were being admitted, he said. He was told he could call the Medical University of South Carolina or Prisma Health telehealth lines and seek a drive-through test, but at that time the state hadn’t opened drive-through testing anywhere in the Myrtle Beach area. He would have to drive more than an hour to get a test.

In the last few days his symptoms have not abated. Now Ventura has been approved for a drive-through test, and he planned to get tested this week at Tidelands Health Family Medicine in Myrtle Beach.

Greg Kelley of Taylors began to feel sick with a fever on March 28. He developed a dry cough and “just a weight” on his chest.

“I wasn’t sure what it was. I thought maybe I had a cold, so I just sort of self-medicated and tried to rest,” Kelly said.

He tried to go into work on Monday and they sent him home, so he logged into a virtual visit with Prisma Health and was told he needed to be seen in person, he said. He went to an MD360 urgent care center where he was handed a mask and sat in the waiting area.

He asked a doctor for a coronavirus test because he had symptoms, had a 1-year-old and an elderly mother in his house, and his wife works at the hospital.

“I told him I really needed to make sure this isn’t what that was,” Kelley said. “He said, ‘Well, they’re not allowing us to give the test to anybody unless you’ve been to New York or out of the country or have been exposed to someone that has a confirmed case... Let’s just hope you don’t have the coronavirus.'”

He was sent home and told to self-isolate.

Testing lag time hampered response

As the state’s health-care providers began to roll out more testing options over the past three weeks, they ran into another logjam that’s further hindered the collection of data to inform response: slow-to-process lab results.

At one point, the state lab ran out of reagent, the chemical needed to cause a reaction in the test, which created a backlog of more than 1,000 cases. The private labs that Prisma used took more than a week to return results, according to Prisma.

So when county emergency managers were responding to the crisis and trying to coordinate supply deliveries, they were left to deal with week-old data for a real-time event.

“The information was 24-hour-old information on a test that was taken last week,” said Jay Marett, director Greenville County Emergency Management, which coordinates the county's emergency response efforts. “Now they’ve remedied that and the turnaround times have improved, so the information is more timely.”

What he’s dealing with still is a lack of specific information about confirmed cases within the county, he said. First-responders need to know if someone is infected when they’re responding to a call, and right now their only hope is that the caller self-reports that they’ve been infected, Marett said.

“One of the many big discussions with the state is that they’re not willing to share the local information with responders as to where the people are so we can have extra protection,” Marett said.

A proposed system for dispatchers to enter addresses to check whether someone in a house has coronavirus isn’t an efficient solution because many dispatch locations don’t have internet access for security reasons and dispatchers are overtaxed with tasks already, Marett said.

He hopes to see a system where responders would have access to information as they’re responding to a call.

Meanwhile, over the course of two weeks, South Carolina’s health professionals began to rapidly expand access to testing. Drive-through testing sites went from two to nine to 14. Hospital systems in Charleston and Greenville began to evaluate some of their own tests in their own labs, greatly reducing the time to see results.

“The faster testing is a game-changer for Prisma Health and our frontline healthcare workers,” said Dr. Scott Sasser, incident commander for Prisma Health’s COVID-19 response. “It will allow us to more quickly identify patients who test negative and otherwise would require the COVID-19-level of isolated care and the use of multiple days of protective equipment throughout their care.”

The state laboratory eliminated its backlog of cases and improved its turnaround time as well, and private labs that had their own issues accessing enough testing supplies also began to catch up.

Officials continue to urge residents to stay at home or work, to distance themselves from others and only shop for essentials in limited trips to stores. And with new research questioning the reliability of the coronavirus test and the potential that those infected may return a false negative test result, assume anyone you come into contact with is infected, officials have said.

Better information changes approach, but some data is still lacking

By April 6, McMaster took the action every other state east of the Mississippi had already taken. He issued a mandatory stay-at-home-or-work order, bringing criminal misdemeanor penalties for breaking it, and moving the state into a new phase of fighting to flatten the curve — preventing a surge of cases needing medical attention at one time — to help medical professionals care for those who will need services.

“Why are we doing this now? Why not earlier? Why not wait later? That is because it is time, according to the data, according to the science, according to the facts and according to the expert advice and guidance,” McMaster said.

South Carolina had begun to issue more information with more widespread testing and public pressure. It made positive cases and estimates available by ZIP code starting this week so residents can better understand their danger and professionals can detect potential emerging hot spots. It also gathered numbers of negative tests from private labs, a key metric to show how many people have been tested and one thast can help detect the peak of the virus, according to public health experts.

"It's going to be critical to have that information to see when exactly it is wise to start going and doing the things we want to do again," Cartmell said. "It becomes less useful for every person to get tested when you've got this many cases, but you still do want a good sampling most everywhere."

Yet South Carolina still hasn’t released some information states across the country have, including the number of patients who have recovered. The state releases only hospitalization numbers once each week, on Wednesdays.

Coroners across the state have also said they don’t have access to accurate numbers of victims who have died from coronavirus and suspect there are others who have died but were never tested.

And people like Kelley, the father from Taylors, were left questioning whether they have the virus at all.

Fortunately for Kelley, he continued to push to get a test because he was told not to return to his job and his wife’s work hours were temporarily cut. Like many South Carolinians, he wanted better information.

He eventually did get a test, and though he’s still exhibiting symptoms, his test came back negative. That has left him with a whole new set of questions.

Check back for more on this developing story.

Nathaniel Cary is an investigative reporter for The Greenville News. He can be reached at ncary@greenvillenews.com or @nathanielcary on Twitter.