Thursday, May 28, 2020

CDC Says Possibly 'Less Than Half' Of Positive Antibody Tests Are Correct

In updated guidance posted on its website over the weekend, the U.S. Centers for Disease Control and Prevention acknowledged an inability to accurately determine if individuals had been infected with Covid-19 via antibody tests; if the test is used in a population where prevalence is low, it's possible that "Less than half of those testing positive will truly have antibodies."

The CDC has acknowledged that antibody testing can frequently be inaccurate, especially in populations where there is a low prevalence of the coronavirus.

Under certain scenarios, "Less than half of those testing positive will truly have antibodies," the agency says.

As a result, the CDC advises that antibody test results should not be used to make decisions related to schools, dormitories, or correctional facilities, and that testing shouldn't be used to determine immune status in individuals.

"The viral testing is to understand how many people are getting infected, while antibody testing is like looking in the rearview mirror. The two tests are totally different signals," Ashish Jha, professor of Global Health at Harvard, told The Atlantic last week.

Antibody tests might be wrong half the time, CDC advises.

Experts urge caution in interpreting COVID-19 antibody tests.

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