Here's Why Your Rapid Test Is Negative Even If You Have COVID-19

Rapid COVID-19 tests can generate false-negative results because they aren't that sensitive, according to a medical expert. Rapid COVID-19 tests, or antigen tests, appear positive if they detect a certain amount of coronavirus -- also known as viral load -- from a sample taken from a person's body, according to BuzzFeed News. Dr. Emily Landon, an infectious disease expert, said that the window when viral load is at its peak can vary from person to person and can range from three days to more than a week as people's systems clear the virus at their own pace. Due to this, it may either take some time for an infected person's result to turn positive or never appear positive if they miss this window or collect their test sample incorrectly, among other things, according to Landon, who is also an associate professor of medicine at the University of Chicago Medicine. "Rapid tests are definitely not like a pregnancy test where it's going to be positive as long as it's been a few weeks after someone missed a period. It's only going to pick it up when you're at peak infectiousness, and they're almost never false positive," the doctor explained.