With increased testing, experts say key indicator is rate of positive tests

MADISON (WKOW) -- Sunday marked the fifth consecutive day with more than 200 new confirmed cases of COVID-19 in Wisconsin. Epidemiologists and doctors have said they expect to see an increase in new cases as the stateramps upits testing capabilities.

Ajay Sethi, an associate professor of population health sciences at UW-Madison, said Sunday Wisconsin is now capable of administering about 11,000 tests per week, nearly three times more than it could not that long ago.

"Just two weeks ago, we were doing maybe 3,800 tests a day," Sethi said. "So, with more testing, we would expect to see more people who are positive."

Sethi said the truly telling data will be the percentage of tests coming back positive. Currently, a little more than nine percent of the more than65,000 tests in Wisconsinhave been positive.

"The last couple of weeks, it's been pretty much hovering around 10%, bouncing a little bit above, a little bit below," Sethi said. "We need to decrease that and that's gonna hopefully occur as long as we can maintain physical distancing."

UW Health Chief Quality Officer Dr. Jeff Pothof said such data is essential as it allows for researchers to more thoroughly conductcontact tracing.He said more potentially-infected people can go into quarantine, paving the way for a safer reopening of the state.

"We can start to isolate those individuals who have the disease, identify people who maybe have come in contact with them and may have been at risk for getting the disease, potentially get those people tested," Pothof said. "That's how you start to gain some control of this virus."

Pothof said he's expecting to see the rate of positive tests decrease simply because tests are now available for people who previously would not have qualified.

"What we would suspect would happen is because we're testing people who are less likely to be true positives, i.e. mild symptoms, it might just be allergies," Pothof said. "Now that we have the ability to test them, the total percent of cases that test and test positive might actually go down a little bit."

Using the data to guide next steps

Pothof added the data also helps hospitals know how much space they have to open back up for non-essential procedures that have been postponed.

"What we've heard from our providers over the past several weeks is that some of these procedures that were postponed, it was safe to postpone them for one month, maybe two months, but not postpone them indefinitely," Pothof said.

One of the key criteria listed in Governor Tony Evers' "Badger Bounce Back" plan for reopening the state is a 14-day decline in the rate of positive tests.

With a portion of the state's residentscalling for Wisconsin to reopen, or at least parts with few confirmed cases, Sethi said a regional reopening is not that simple.

"Wisconsin is a beautiful state, there are people who travel across the state in the summer to take advantage of what the state has to offer," Sethi said. "So, if we want to reopen a specific county because we don't think there are a lot of cases, we also have to close the borders of that county from people who want to visit."

Sethi said to help epidemiologists forecast possible future hot spots or a coming decline in cases, geography professor Song Gao hascreated a dashboardthat shows county-level data on people's movement. The system uses GPS data from people's cell phones to track the extent to which the public has decreased its movement.

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