If you think a negative test result means you don't have coronavirus, you could be wrong.

It can take days before a new infection shows up on a COVID-19 test.

"We know that the incubation period for COVID-19 is up to 14 days. And before that, you can be testing negative, and have no symptoms," emergency medicine physician Dr. Leana Wen told CNN. "But you could actually be harboring the virus and be able to transmit it to others."

So if you want to get tested as a precaution before seeing friends or family, here's what you need to know: If I got infected yesterday, would a test today pick that up?

Probably not. A study in the medical journal Annals of Internal Medicine examined false-negative test results of people who actually had COVID-19.

The study estimated that during four days of infection before symptoms typically started, the probability of getting an incorrect/negative test result on Day 1 was 100%.

So what should I do if I want to see friends or relatives?

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