State health officials announced a change to the way they will calculate the percent positive of COVID-19 tests going forward on Tuesday.
The calculation change brings the state in line with others and is a better measure of spread, officials say, but slightly lower positivity rates should not be used as indicators that COVID-19 poses any less of a risk in the state.
On Thursday, the South Carolina Department of Health and Environmental Control reported 1,649 new confirmed cases from 23,653 individual tests, making 10.1% of today’s tests positive.
“It is important that people understand that while percent positive appears as a smaller number under the new way of calculating the rate, COVID-19 continues to spread at an elevated level in our state. That smaller number is solely based on the change in the way we calculate the rate,” said state epidemiologist Dr. Linda Bell, in a statement on Tuesday.
The federal Centers for Disease Control and Prevention (CDC) uses the new method as well.
Previously, the South Carolina Department of Health and Environmental Control was calculating the percent positive using the “people over people” method by comparing the total number of new people with positive results to the combined total number of new people with positive and negative results. That method did not account for people who were tested twice, officials say.
The newly adopted “tests over tests” method is a straightforward comparison of the total number of positive tests compared with the combined total number of positive and negative tests.