7 things to know about COVID-19 antibody testing

As more people recover from the novel coronavirus and seek to resume their normal activities, there’s been a lot of talk about testing for COVID-19 antibodies. But what are antibody tests, exactly, and how do they differ from diagnostic tests for COVID-19? What do the results indicate for the people who take these tests? And what do they mean for how we should conduct ourselves during the COVID-19 pandemic? To learn more about COVID-19 antibody testing, we spoke with Laboratory Director James Kelley, M.D., Ph.D. Here’s what he had to say. What is antibody testing, and how does it differ from diagnostic testing used for COVID-19? Diagnostic testing for COVID-19 involves looking to see whether an active virus is present — in this case, the coronavirus formally known as SARS-CoV-2. Laboratory technologists use a testing process to detect genetic material from the virus in samples swabbed from the very back of the nasal cavity. This testing is based on a common molecular testing technique: polymerase chain reaction (PCR). By contrast, antibody testing (also called serology testing) is done with blood samples, because you’re looking for evidence of the body’s immune response to the virus. After your body is exposed to a foreign pathogen, your white blood cells start to learn about it and make antibodies to neutralize it. So, when an antibody test comes back positive for this coronavirus, it means 1) you were exposed to SARS-CoV2 at some point in the past and 2) your immune system was robust enough to launch an antibody-forming immune response. How long does it usually take people to generate these antibodies? There...