A sensitive test will correctly identify people with covid. Sensitivity measures correct positive results.
If a test is 90 percent sensitive, it will correctly identify 90 percent of people who are infected. However, 10 percent of people who are infected and tested would get a false negative result—they have the virus, but the test said they don’t.
A specific test will accurately identify people without covid-19. Specificity measures correct negatives.
If a test is 90 percent specific, it will correctly identify 90 percent of people who are not infected. However, 10 percent of people who are not infected will test positive for the virus and receive a false positive.