The number of reported coronavirus cases in Alabama dropped in the last day due to a lab error that incorrectly listed negative test results as positive ones.

On the afternoon of April 17, an outside entity mistakenly marked COVID-19 lab test results as positive when they were, in fact, negative, the Alabama Department of Public Health said Saturday.

“The error was rapidly discovered by the Infectious Disease and Outbreaks Division and ADPH Data Team. The ADPH Data Team has been working since (Friday) to correct this information and advises it could take a few days to completely resolve the information from the outside entity. The entity is cooperating with ADPH in this effort and has reached out to providers who ordered tests through their facility.”

“ADPH closely monitors data transmitted to us, as the accuracy of information is vital to the COVID-19 outbreak response,” the state health agency said.

Screenshots from the ADPH coronavirus tracker show 4,571 cases on April 17, dropping to 4,500 by Saturday morning. It’s not clear how many of the mistaken tests were included in the total vs. new positive tests that were reported. As of 9 a.m. yesterday, Alabama had 4,404 positive cases of COVID-19 and has been averaging about 4 percent growth over the last several days.

Private labs are required to provide ADPH with both positive and negative test results but as the ADPH tracker notes, not all are providing information on negative tests. There have been small changes in county-by-county numbers from one day to the next when a person is listed in the wrong one, or found to be living out of state.