The review shows that antibody tests could have a useful role in detecting if someone has had COVID‐19, but the timing of when the tests are used is important. Antibody tests may help to confirm COVID‐19 infection in people who have had symptoms for more than two weeks and do not have a RT‐PCR test, or have negative RT‐PCR test results. The tests are better at detecting COVID‐19 in people two or more weeks after their symptoms started, but we do not know how well they work more than five weeks after symptoms started. We do not know how well the tests work for people who have milder disease or no symptoms, because the studies in the review were mainly done in people who were in hospital. In time, we will learn whether having previously had COVID‐19 provides individuals with immunity to future infection.
Further research is needed into the use of antibody tests in people recovering from COVID‐19 infection, and in people who have experienced mild symptoms or who never experienced symptoms.
https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013652/full#.XvTDGHEkVz4.twitter