Flu and COVID test combo for home is now available: Does it work?

“This really matters, because if somebody does have the flu, we can actually intervene and prescribe Tamiflu or other antivirals that would benefit patients,” said Dr. Scott Roberts, an infectious disease specialist at Yale Medicine.

This fall, the Food and Drug Administration granted the first marketing authorization for a combo flu and COVID-19 test to the Healgen Rapid Check COVID-19/Flu A&B Antigen Test.

There are also a number of combo COVID-19 and flu tests that were granted emergency-use authorizations (EUA) by the FDA last winter, including those from iHealth, OSOM, and Lucira, which cost between $25 and $30 online.

Healgen’s marketing authorization means that the product has undergone a more thorough safety review, but it is not yet widely available to consumers. The other FDA-authorized combination tests are comparable, experts said.

The tests work for ages two and up, and those under the age of 14 should have an adult administer the test for them.

The combo tests work best when people are symptomatic, said Dr. Sabrina Assoumou, an associate professor at Boston University School of Medicine and infectious diseases physician at Boston Medical Center.

“You need to have symptoms when you reach for this,” said Assoumou. “Because if you use it and you don’t have symptoms, it may not be as accurate.”

According to the FDA, the Healgen test correctly identified 99 percent of negative and 92 percent of positive samples of SARS-CoV-2 samples; it also identified 99.9 percent of negative flu A and B samples and 92.5 percent of positive flu A and B samples.

Comparatively, the Lucira test correctly identified 99.9 percent of negative and 88.3 percent of positive COVID-19 samples; it also identified 90 percent of positive and 99.3 percent of negative flu A samples. For flu B, which is not widely circulating right now, it identified 99.9 percent of negative samples.

Experts recommend testing at the onset of symptoms and again every 48 hours if the first test is negative and symptoms grow worse.

Roberts said that his biggest concern with at-home testing is whether people administer the tests correctly.

“Similarly to COVID-19, there is this risk of a false negative, where maybe somebody doesn’t swab far enough back in their nose or the test is expired or the ingredients are dried out, for whatever reason,” he said.

False positives are less of a concern.

“People who want to know which one they have [COVID or flu], because the symptoms overlap so much, getting a positive result on one and not the other would be useful in terms of seeking out treatment,” said Dr. Paul Sax, clinical director of Division of Infectious Diseases at Brigham and Women’s Hospital.

The biggest thing to remember, Roberts said, is to closely follow the instructions on the packaging since each test is slightly different.

And like any time of year, Assoumou said to think of testing as one part of a “layered approach” to preventing respiratory illnesses like the Flu and COVID-19.

“Testing is very important, but it’s … one of those layers,” she said. Vaccination, testing, masking, and ventilation of indoor spaces where people gather “are all the different measures that are going to help us get to the other side.”

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Izzy Bryars can be reached at izzy.bryars@globe.com. Follow her @izzybryars.