A week into the city’s declaration of a civil emergency, the Shelby County Health Department announced Friday, March 27, that 2,218 people have been tested for COVID-19 within the county since the public health crisis began.

With 228 confirmed cases in Shelby County as of Friday morning, the total number of those tested — positive and negative — would come to a 10% positivity rate. That’s assuming the number of those tested does not include test results that are pending, which would make the percentage lower.

The statistic does not reflect the infection rate in Shelby County, which is now impossible to know for certain. Instead it’s the percentage of tests that were positive among people who had symptoms and qualified for testing.

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Getting accurate numbers is a problem nationwide because of discrepancies in testing procedures that muddle the picture.

The first numbers on local testing that includes those who tested negative for the virus comes ahead of an expected surge of confirmed cases and as more testing becomes available locally. Statewide, a total of 16,091 had been tested as of Friday afternoon.

“The testing resources have been strained but they are improving daily,” Tennessee Gov. Bill Lee said Friday during a Memphis visit. “The more we do that, the more likely we will blunt the curve and provide for our health care system to accommodate the coming surge of COVID-19 that is coming to our community for certain.”

Prior to Friday’s release, the Shelby County Health Department had refused to make any local numbers or estimates public but used them in consulting with other health professionals dealing with the crisis and told those professionals not to release them either.

Lee announced Friday that state rules for reporting negative as well as positive tests are changing and will be reflected in state numbers.

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By state regulations, hospitals, clinics and labs who do such testing had only been required to report positive tests to county health departments. They reported the total number of those tested regardless of the results to state health officials. But county health officials couldn’t get those results broken down by counties.

Lee released the number tested statewide Wednesday but not a county-by-county breakdown. Shelby County Health Department director Alisa Haushalter was awaiting the state numbers for each county as she attempted to change the reporting procedure for testing.

“If we don’t know who has the virus then we can’t contain the virus to the degree we would like to,” Lee said. “Understanding the numbers of testing will allow us to understand the capacity to which we are reaching Tennesseans.”

The local number covers a period when the vast majority of testing in Shelby County was by a referral or appointment for testing scheduled by physicians. The University of Tennessee Health Sciences Center drive-thru testing on Tiger Lane at the Fairgrounds began allowing testing without a doctor’s recommendation Friday but is still requiring that those to be tested schedule an appointment online.

Drive-thru testing available at Tiger Lane, by appointment

Dr. Jon McCullers, pediatrician-in-charge at Le Bonheur Children’s Hospital and a dean and infectious diseases expert at the UTHSC, cautioned that the number reported is not the current testing rate. It’s all tests done so far across a time period where conditions and the effort to quell the pandemic have been changing.

“It is likely that early on when tests were only administered using stringent criteria including exposure or travel, that the percentage positive was much higher,” he said in an email response to The Daily Memphian.

In recent days, McCullers estimates a positivity percentage of 5% to 6% in local hospitals and 3% to 4% at the Tiger Lane Fairgrounds drive-thru testing site.

“When added all together, it is around 10%, but that masks the changes in the percentage positive as testing expanded more broadly and to less-ill populations,” he said. “It would be very helpful to see daily reporting of the numbers. If the percentage positive starts to increase, this likely means increasing spread within the community. We are in fact lower than other severely affected areas, like NYC, which is good.”

Lee and other elected leaders who are not medical experts are focused on the testing numbers to determine whether to ramp up emergency orders limiting the movement and congregation of citizens in public places.

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“There’s a lot of evidence that the cities in other countries and the countries themselves that have the greatest level of testing during this pandemic, those countries have the best outcomes with regard to flattening the curve,” Lee said. “It’s a challenge. Having the resources – testing has ramped up slowly in a lot of places. But we feel very good about our capacity and the increasing capacity we have to test.”

In trying to figure out how many people have been tested countywide earlier, The Daily Memphian gathered testing numbers from some but not all of the city’s hospitals and clinics. Some refused to release their numbers saying the Health Department would have to. Still others released numbers for how many were tested but not results.

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Friday’s countywide total was a single number with no detail. The state testing numbers offer detail like the types of labs and their numbers by category and age ranges of those tested.

The state health department’s release also warns “These data are meant to provide a rough estimate of testing volume. Due to different source data, numbers may differ slightly from day to day.”

Baptist Memorial Health Care provided the most detailed numbers of the set and had a positivity rate of 8.8% just for its numbers at its institutions with Shelby County as assembled by The Daily Memphian.

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As of Friday afternoon, the positivity rate at the Baptist Memphis facilities was 7.4%

“I’m slightly optimistic that we have not seen a large increase in the percentages of positives,” said Dr. Stephen Threlkeld, Baptist infectious disease expert who is treating active cases,

“Some of it could be that we are testing less and less ill people. We have a very large capacity to test and it’s human nature to want to know. People are curious to see if they have the illness,” he said. “The positives are not going up dramatically in percentages. We haven’t seen that yet. I don’t doubt that it will happen. We obviously think it will. People talk about the surge, and there is no question other cities have seen very large increases in cases.”

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Because most of the patient modeling is based on what happened in China, Baptist is gathering data on its patients with COIVD-19, drilling down to understand why some cases are worse than others. That includes looking at what medications are being taken independent of the virus, what medications are being taken for the virus and demographics. The data is being shared with other medical centers in the country.

“We do have something of an advantage here,” Threlkeld said. “We started the processes, including social distancing, sooner. And we are more innately more spread out than a lot of the cities hit with this.”

Baptist doctors did what is believed to be the first test for COVID-19 locally in late February, weeks before the World Health Organization declared the outbreak a pandemic.

At a Wednesday briefing, Haushalter gave a cautious and highly qualified estimate of a 3% positivity rate.

“Again, it’s incomplete as far as the number of tests,” she said.

She refused to make the number tested public then because she said she didn’t believe the number she had was accurate.

“And we understand the importance of having that total number as well as those positive for that positivity rate,” Haushalter said. “But we are not going to release information that is inaccurate.”