What you should know about rapid antigen tests

The United States is once again watching coronavirus cases and hospitalizations rise as summertime nears. Nearly half of Americans – 45 percent – are living in communities with medium or high community levels of COVID-19, particularly in the Northeast and Midwest, and experts say the real numbers are likely far higher. 

With little public masking and official tests undercounting the true scale right now, people must rely on personal decision-making more than ever. Though COVID deaths haven’t yet begun to mirror the latest uptick, the U.S. recently hit the grim milestone of 1 million record COVID deaths, and that number continues to climb. 

So what can Americans be doing now to slow or limit the spread of the virus? And how does at-home testing fit into the picture? 

“Antigen tests are one of the most underutilized tools of this pandemic,” epidemiologist Katelyn Jetelina told PBS NewsHour digital anchor Nicole Ellis in a recent conversation. 

Jetelina, who writes the Your Local Epidemiologist newsletter about the science of the pandemic, offered some advice about the best times and ways to use this tool. 

Watch the conversation in the player above. 

Why should you use an antigen test instead of a PCR test?

Jetelina explained they are two different tools with different benefits.

Both types of tests typically use a nasal swab to collect a sample, but antigen tests look for a specific protein carried by the virus, while a PCR (or polymerase chain reaction) test tries to match the virus’ genetic material. 

A negative test result for either type of test does not ensure that you do not have COVID – it means the test did not detect it. But antigen tests are “really good at telling us if we’re infectious or not,” she said during the May 17 conversation.

“This is very different than PCR tests. PCR tests just tell us if we have the virus in our system or not. It doesn’t tell us whether we’re contagious or not,” Jetelina added.

The omicron variant has thrown a little wrench into the timing of rapid testing, she said, because people are becoming symptomatic earlier than with past variants. Jetelina recommended waiting 24 hours after symptoms develop before you use an antigen test. 

How should you use an antigen test if you know you have COVID?

One benefit of antigen tests is that when someone with a positive COVID result has been isolating for several days, a negative rapid test can signal that they are no longer contagious and it’s safe to see others.

If you know you have COVID or have symptoms and are waiting for a test result, the current recommendation from the Centers for Disease Control and Prevention is to isolate for five days and to wear a mask in public for an additional five days. But that policy isn’t always foolproof, Jetelina said. 

WATCH MORE: White House COVID response coordinator Dr. Ashish Jha discusses the growing virus surge

“The current recommendation right now is that five days after you’re symptomatic, you can leave isolation,” she said. “But what we’re seeing is that people are still contagious seven, 10 and 12 days later after the first symptomatic disease.” So a negative antigen test can offer greater reassurance.

When else should you use an antigen test?

“At-home testing is a really great tool to use to break transmission chains, especially if you just came back from a high-risk activity. For example, maybe you went to a concert and you don’t want to bring the virus back to your family,” Jetelina said.

It’s also a good idea to test yourself right before you’re planning to visit someone who is vulnerable, like a loved one who lives in a nursing home.

Most insurance providers, including Medicare Part B, state Medicaid plans and CHIP will pay for at-home rapid tests. Private health insurance  must cover up to eight rapid tests per member per month. Depending on the provider, rules can vary on whether you can pick them up for no out-of-pocket cost or whether you have to apply for reimbursement. Rapid tests can also be paid for or reimbursed with a flexible spending account (FSAs) or health savings accounts (HSAs), according to the IRS. In addition, the White House announced this month that they are making another round of free at-home antigen tests available by mail.