BUFFALO, N.Y. (WIVB) — With the federal government offering up to four free at-home Covid-19 test kits per household, some people have questions about how they work. News 4 spoke with Dr. John Crane and Dr. Nancy Nielsen with the University at Buffalo’s Jacobs School of Medicine to get some answers.
How do the at-home Covid-19 test kits work?
Dr. John Crane: These are little kits that come, they include the swabs, they include usually a little cassette or a little device, in which you insert the swab once you’ve obtained your specimen. For the Binaxnow kit, which is the one the federal government is sending out for those who request it, each box contains enough to do two tests.
The way you’re supposed to do it is you’re supposed to swab each nostril five times in a circular motion. Twizzle around five times in both nostrils and then you insert it in the little device and you add the liquid and then you have to wait. It’s either ten minutes for some kits or fifteen for other kits. It’s similar to a urine pregnancy test.
There’s a control line that shows that the kit is working, and then there’s a test line and if that one turns color and it’s usually pink or purple, that means the test is positive.
When should you use the at-home Covid-19 test kits?
Dr. Nancy Nielsen: There are three situations that are pretty clear.
- If you have symptoms that you have Covid-19 and you have a test available, take it. If it’s positive you can be pretty sure. If it’s negative, you probably don’t have Covid-19, but it’s not absolute.
- If you are exposed to somebody. But, the timing is important. It should be five days after you’ve encountered that positive person. Don’t do it the next day. If they got sick last night and did a rapid test this morning, don’t do the test today. It won’t be positive yet and you could still be infected.
- If you’re going to to be around a lot of people indoors or even with a few people. Although they may all be vaccinated you want to be sure that you’re safe to go to this gathering. If it comes back negative, that gives you a point in time, but it’s still good to do a second test the next day or the day after that.
How accurate are these tests compared to the PCR test or the rapid test?
Dr. John Crane: They are not as sensitive as the polymerase chain reaction, or PCR kits, which are still considered the gold standard. But they are pretty good. For people who actually have symptoms, they are about 75%-80% sensitive in detecting the coronavirus. Now if you’re just doing it on asymptomatic people, the sensitivity is less.
Dr. Nancy Nielsen: If you’re symptomatic and you use a rapid test and you get a positive, you can be pretty sure you have Covid-19 and you can act accordingly. Where they are not as good as if you have no symptoms. There they are not as wonderful and you should be very judicious in how you use these.
Can at-home Covid-10 tests give false-positive results?
Dr. John Crane: The false-positive rate is low. I can’t say it would never happen. Of course, it could happen if people don’t follow the instructions.
There are apparently videos and posts on social media of people who have made the tests turn positive, false positive on purpose, by dribbling vinegar, or hydrogen peroxide, or home chemicals to try to force it into giving it a false reaction. Those people then say, oh the test is not reliable, but that goes way beyond what the test was intended to do.
What is the next step if I test positive?
Dr. Nancy Nielsen: Simply call the health department or go online and let them know because that’s the responsible thing to do. They are not going to bug you. They don’t have the personnel to do that, to do contact tracing. And then it’s your responsibility to talk to people you’ve been in contact with that you might have infected.
How can I sign up for the free at-home Covid-19 test kit from the federal government?
Dr. Nancy Nielsen: They had a soft launch on Tuesday. All you have to do is enter your name, your address and submit and that’s it. And then about 20-25 minutes later I got a notification from the U.S. postal service that my order has been noted and it would be about two weeks.
Report a positive Covid-19 home test result here.
Abby Fridmann is an anchor and reporter who joined the News 4 team in November 2020. See more of her work here.