5 On Your Side examines COVID-19 rapid test accuracy

Free COVID-19 rapid tests from the federal government are starting to arrive in mailboxes.

With a half-billion of these at-home tests being sent out right now, 5 On Your Side wanted to know how accurate they really are.

We reached out to Dr. Bruce Tromberg, head of Rapid Acceleration of Diagnostics, otherwise known as RADx.

RADx is the initiative to speed up the innovation and development of COVID-19 testing technologies.

So what’s the big difference between a lab PCR test and an at-home antigen test?

"You have to think of it a little bit differently than a PCR test," Dr. Tromberg told 5 On Your Side.

"If you don’t have that much virus inside you, then a PCR test is going to pick it up and an antigen test won’t," said Dr. Tromberg.

Basically, antigen tests aren’t as good at detecting low levels of COVID-19 that are present during the early stages of infection. So, taking one rapid test and getting a negative result, is not enough to be sure that you do not have COVID-19.

However, Dr. Tromberg said, "If you’ve got three negatives (antigen test results), statistically, you’re very likely to be negative, especially if you’re asymptomatic."

Dr. Tromberg suggested waiting a couple of days between each test. He also told 5 On Your Side that rapid test performance has held up well against all COVID-19 variants, including Omicron.

Another resource he suggested is whentotest.org. Answer a few questions at that site and it tells you how likely you are to have or spread COVID-19, based on where you live.