The best time to take an at-home COVID-19 test may be on the fourth day of having symptoms, according to a study published in the journal Clinical Infectious Diseases.
Researchers looked at nearly 350 people and found that viral load peaked a few days after symptoms started.
“Viral load just refers to the amount of virus that is replicating in your body, So the more virus that is replicating, the more chance of a test turning positive,” said John Brownstein, Ph.D., chief innovation officer at Boston Children’s Hospital and an ABC News Contributor.
“Right at the beginning point of an infection, there’s limited viral copies. But as the infection progresses, you’ll have an increasing amount of virus replicating in your body,” he added.
The study found that at-home tests were most accurate on the fourth day of symptoms. They could still pick up some infections in the first three days but were more likely to be negative. The findings show that people should not be able to rule out COVID-19 just based on a negative test early on after symptoms start, the study authors said.