As the novel coronavirus pandemic continues, many people have experienced the phenomenon of receiving negative results on an at-home test, only to test positive at an urgent care clinic or doctor's office. While the accuracy of these tests is generally sound, experts have put forward some theories as to why this may be occurring.
Molecular biologists do not expect the latest variant, XBB, to have any effect on the accuracy of at-home rapid tests, as the part of the virus that these tests are designed to detect, the nucleoprotein, has stayed consistent. Other potential factors for false negatives include repeat testing, low viral load, and the virus interacting with our cells differently.
Experts recommend that if you have symptoms or have been exposed to someone with COVID, you should get tested at least twice 48 hours apart, and if you are asymptomatic, three tests 48 hours apart. For those at risk who keep testing negative, experts suggest getting a PCR test sooner rather than later. Those with mild symptoms who feel like they are recovering may wait a couple of days and check in with their health care provider if they still feel unwell.
Overall, while at-home tests are generally accurate, there are certain scenarios in which a false negative may occur. It is important to follow the advice of experts and, if deemed necessary, to get tested multiple times or seek medical advice.