A positive result that is incorrect is called a false positive. False positives occur when a person tests positive even though they do not have the infection.
A negative result that is incorrect is called a false negative. False negatives occur when a person tests negative even though they have the infection.
False negatives and positives can worsen the COVID-19 pandemic by providing false reassurance to those who have the infection or by causing those who do not have it to use critical resources.