Do Rapid Tests Pick Up Omicron?

When RSVP'ing to holiday party invites, many have also agreed to take a rapid, at-home COVID-19 test before heading out the door.

But the rise of Omicron has left people wondering whether these rapid antigen tests can still detect the virus.

The short answer is yes, but there are some caveats.

Omicron's heavily mutated spike protein has increased its potential to evade our immunity, even our vaccinated immunity. But most rapid, at-home tests detect the virus' nucleocapsid protein instead, according to long-time advocate of rapid testing Michael Mina, MD, PhD, formerly of Harvard and now chief science officer at a biotech software company.

"Omicron has 4 mutations in N [nucleocapsid]," Mina tweeted. "Two were in Alpha/Delta and were fine. Two are in ... a non-immunogenic site [and are] unlikely to impact rapid tests."

Amy Karger, MD, PhD, a clinical pathologist at the University of Minnesota, told MedPage Today late last week that some manufacturers have issued statements that their rapid tests do, indeed, detect Omicron.

Abbott, which manufactures one of the most popular rapid, at-home tests -- BinaxNOW -- issued a statement that both its antigen and PCR tests can pick up Omicron.

"While the Omicron variant contains mutations to the spike protein, Abbott's rapid and molecular tests – antigen and PCR – do not rely on the spike gene to detect the virus," the company said in its statement.

While Karger noted that there are no "rigorous, independent studies" on rapid test accuracy in the context of Omicron, she said that she doesn't "see anything to indicate that we're going to have trouble detecting it with these at-home tests."

And there's no longer a need to just take companies' word for it. On Friday, the U.K.'s Health Security Agency published its latest update on the Omicron variant, and it included a look at how well five of its lateral flow tests (another name for rapid antigen tests) detect the variant.

While it didn't include the most commonly available U.S. brands -- such as BinaxNOW, BD Veritor, On/Go, and iHealth -- experts said the technology is comparable to those that were analyzed.

Though each only tested about 15 samples at different dilutions, there were no false negative results.

Mina noted that there could be some caveats: "If Omicron is able to more efficiently replicate in bronchus (not measured in nasal swab), lyse & release from cells much more efficiently, then we may be in a situation where the amount of virus measured in the nose on any test may not correlate as well with exhaled virus."

In addition, if Omicron replicates faster, there may be a shorter window for results to be accurate. Theoretically, it's possible that if someone tests negative at 4 p.m. but stays at a party until 11 p.m., her status could change in that time.

Still, Mina said, "all the data is in fact showing the rapid tests DO detect Omicron as well as they detected Delta."

Even with full confidence in rapid, at-home tests, accessibility remains a challenge. Stores have been selling out, and online ordering has been spotty.

When tests are available, their prices are high -- about $25, on average, for a kit that contains two tests.

The government should be subsidizing the tests, because they're public health tools and could help curb the spread of COVID-19, said Carlos del Rio, MD, of Emory University in Atlanta, in a previous interview with MedPage Today.

"It's really a travesty these aren't being subsidized appropriately," del Rio said.

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