April 13, 2020 / By Erika Edwards
As Americans look toward a return to normalcy after the coronavirus pandemic, a major question will be: Who is immune to the virus? To answer that question, the promise of antibody tests looms large.
These tests are different from the diagnostic tests used to determine whether a person is sick with the virus. Instead, the tests look for the antibodies in a person’s blood that the immune system makes in response to an infection. 
Knowledge of who has antibodies could tell the estimated 25 percent of people who had asymptomatic infections that they did, in fact, catch the virus. And it would, in theory, answer the question of if and when anyone who has recovered from the illness could return to work safely.
The Centers for Disease Control and Prevention is among the institutions in the United States that is investigating antibody testing for COVID-19.