By Holly Yan, CNN 7 hrs ago
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…