While they’re considered the gold standard for a COVID-19 diagnosis, PCR tests are unnecessary for those who have already tested positive on an antigen test. They’re able to detect smaller quantities of the virus and detect them sooner (and for more time) than antigen tests. PCR tests, which are still mostly done at hospitals and other testing facilities rather than at home, are far more sensitive than antigen tests.

That’s why I tell people they should trust a positive antigen test, but be more skeptical about a negative one. If someone has COVID-19, but hasn’t yet reached the test’s threshold of viral particles, they may still test negative with an antigen test but positive on a PCR test. But a negative antigen test doesn’t necessarily mean you aren’t contagious. Rapid antigen tests detect COVID-19 when people have a higher amount of virus particles in their system and are more contagious. Rapid antigen tests, which you can buy in most pharmacies, are great in specific circumstances and less good in others. Q: How are rapid antigen tests different from PCR tests? Is one better than another? Stay isolated if you have any symptoms, even if you cannot quickly get a COVID-19 test. People who are unvaccinated or immunocompromised may still get severe disease. Symptoms may include sniffles, congestion or a cough, and might resemble a mild cold, especially in fully vaccinated and boosted people.Įven if you have minor symptoms, you are still contagious. Isolate and get a COVID-19 test if you have any symptoms of COVID-19, even if they’re mild and even if you’re fully vaccinated and/or boosted. These include when to get a COVID-19 test, what kind you should use, what to do if you can’t get one at all, and why it’s still important to get vaccinated and boosted. As the very infectious Omicron variant of COVID-19 surges around the country, you need to know what kind of tests to take to protect yourself and your community.Įmily Landon, infectious disease expert and executive medical director for infection prevention and control at University of Chicago Medicine, answers common questions about COVID-19 tests.

Rapid covid testing