Covid-19 testing: How to pick the test that's right for you

Yahoo Medical Contributor, Dr. Dara Kass, breaks down the different types of Covid-19 tests, how to use the results and how to safely visit friends and family this holiday season.

Video Transcript

DARA KASS: In advance of the holidays, we're seeing an enormous number of people go to get tested voluntarily, regardless of whether or not they have symptoms of COVID-19. So we're going to break down what kind of tests are out there, what to do with the results, and whether or not it gives you permission to just go and see your family like it's a regular year.

Well, there's basically two different kinds of tests. There is the PCR test and the antigen test. The PCR test will find a smaller piece of virus, because of how they look for the virus DNA. The PCR test can either be rapid or it can go to a lab. That lab can take anywhere from 24 hours to actually up to a week, or even two, to get results.

The antigen test looks for a piece of the virus on the outside. And they're going to come back some around 15 minutes. Both tests will probably tell you if you're positive, and probably be accurate if you're negative. If you're symptomatic and you need to get tested, you probably should try to find an antigen test, one they can come back very quick and tell you, do you or don't you likely have the coronavirus? If the rapid test gave you results you weren't expecting, you should go and get a PCR test just to confirm and send it to a lab.

Neither test was really created to screen people who are asymptomatic. When you get exposed to the virus, you actually don't convert to being positive right away. In fact, most people probably won't convert till about day three, maybe day five. So testing just after you find out that you've been exposed is definitely not useful. So let's break that down.

Day one, you get exposed. And so you decided on day five to get tested. Day five you're negative, so you feel like you're all clear. Day eight, you go have a meal. Maybe it's a drink with other people. And then day 10, you start to feel pretty bad.

The virus is in your body. Your body's trying to fight it off. But finally, the virus replicates enough copies to make you not only symptomatic, but contagious. And that can take up to 14 days. And it is definitely possible that day eight, when you had that meal or that drink, you could have passed that virus onto other people.

Please be aware of the environment around you. If you find out that the testing times are taking two, three, or four days to return results from a lab or you see lines that are maybe two, three, or four hours long, it's probably not the best time to take resources away from those who likely need it to make sure that they don't have the virus if they've been exposed or symptomatic.

It's probably true that if you have antibodies, you can't really get the virus again while you have those antibodies. And you're probably not able to spread it to anybody else. But since we don't know that for sure, we still ask people, like me, to still wear a mask and stay distanced and be responsible.

If you're gonna try to see your family for an event or a holiday, the best practice would be to quarantine for up to 14 days, test yourself right before if you can, and remember that if you're inside, please wear a mask. And if you're outside, please be six feet apart. If you're going to eat a meal with people that are not in your nuclear family, pretend you have your own restaurant, and each family has their own table.

But no matter what you do, every single measure you put into practice while you're gathering keeps that event safer in the event that somebody actually had this virus.