Demand for coronavirus tests is increasing as the economy continues to reopen, Louisville chief health strategist Sarah Moyer said.
She said people with symptoms of COVID-19 should be the first priority for testing, followed by those with known exposures, especially in closed settings such as jails or nursing homes.
That's different than the approach in some states, such as Indiana, where anyone is encouraged to get a test, regardless of symptoms. In Kentucky, people without symptoms or known exposures can get tested. There are several sites in Louisville that offer that service to the general public.
But Moyer said everyone shouldn't rush out to get a test.
"If you've been home and you're staying home and only going out to the grocery store, and feel great, I'm not encouraging testing in those people, so we can keep those spots open for those that really need it," she said.
It is taking longer to get results back from some national labs, Moyer said. Where results used to come back in 24 hours, now they sometimes take up to 10 days.
She also said the test is imperfect, sometimes delivering false negatives that make people feel like "they can go out and do what you want."
But with 280 new confirmed cases over the past week and an additional 10 deaths, officials said it is essential for Louisvillians to continue wearing masks and maintaining six feet of distance from others in public.
Moyer said those measure could help prevent "clusters," or a concentration of infections in the same place all at once. And that could the best way to decrease the rate of community spread, she said.
Mayor Greg Fischer says in the city, there have been 70 new cases reported since Wednesday.
"Two, three, four weeks ago, it was like 30 to 40 new a day, sometimes 20 to 30," he said. "So you're seeing a doubling in that number. We are testing more. That's true."
The city's positivity rate, which represents the number of positive tests out of the total number tested, has held steady recently, he said. That means that even as more people get tested, the proportion of cases isn't increasing significantly.
The current positivity rate is 7.45% percent, according to a new public COVID-19 dashboard for Louisville that city officials unveiled Thursday. The World Health Organization recommends a positivity rate of 5%.
"A low rate of positivity in testing data can be seen as a sign that a state has sufficient testing capacity for the size of their outbreak and is testing enough of its population to make informed decisions about reopening," according to the Johns Hopkins University of Medicine Coronavirus Research Center. It lists Kentucky as among the states not meeting the WHO's recommendation, with a rate of 6.37% as of Thursday morning.
Fischer said some labs only provide the results for positive tests, which means the city doesn't know exactly how many negative tests are out there. This can affect the positivity rate by forcing the calculation to consider a lower number of total tests than actually exists.
But Grace Simrall, the city's chief of civic innovation and technology, who worked on the reporting dashboard, said there is enough data to observe that as testing has increased, the proportion of positive results hasn't increased with it.
The dashboard's data on cases, deaths and recoveries will update daily, while other details such as the positive rate will be reported weekly.
