May 22, 2020 - Health

CDC is conflating diagnostic and antibody tests for coronavirus

A CDC screen
Photo: Pavlo Gonchar/SOPA Images/LightRocket via Getty Images

The Centers for Disease Control and Prevention on Thursday confirmed that it has been combining the results of diagnostic coronavirus tests and coronavirus antibody tests, The Atlantic reports.

Why it matters: Including antibody test results distorts data on the prevalence of the coronavirus and can overstate the ability to safely begin the reopening process.

  • A positive COVID-19 test means a person is currently carrying the coronavirus, while a positive antibody test suggests the individual has been infected in the past.

What they're saying: Harvard professor of global health Ashish Jha told The Atlantic, "Because antibody tests are meant to be used on the general population, not just symptomatic people, they will, in most cases, have a lower percent-positive rate than viral tests."

  • Jha says the CDC's combination of the two tests makes their results "uninterpretable," and that the distortion will "drive down your positive rate in a very dramatic way."
Go deeper