FDA on Thursday authorized the InspectIR Covid-19 Breathalyzer, the first test that uses breath samples to detect the coronavirus. According to experts, the development is promising—but the technology has its shortcomings.

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Details on the test

To use the test, a patient blows into a cardboard straw attached to a chemical analyzer for up to 10 seconds. The machine then analyzes the levels of five volatile organic compounds (VOCs) that make up a "breath print" of Covid-19, according to John Redmond, co-founder of InspectIR Systems. The test delivers results within three minutes, InspectIR said.

"It's a chemistry lab in a box," Redmond said.

According to FDA, a study of 2,409 people found the breath test correctly identified a positive Covid-19 sample in 91.2% of cases and correctly identified a negative Covid-19 sample in 99.3% of cases. A follow-up study of 12 symptomatic patients in Texas, conducted during a time in which omicron accounted for the majority of all cases, found the test was 90.9% accurate.

According to FDA, patients who test positive using the breath test should have their results confirmed with a PCR test.

The potential impact

Experts said the prospect of detecting Covid-19 via a breath sample is promising, but they said the test has its flaws and isn't likely to supplant nasal swab tests entirely.

One limiting factor is how quickly the company can ramp up production. According to InspectIR, the company intends to produce "approximately 100 instruments per week, which can be used to evaluate approximately 160 samples per day." This means the breath test is "expected to increase [testing capacity] by approximately 64,000 samples per month."

It could take 10 to 12 weeks for the first devices to hit the market, Redmond said. While pricing has not been finalized, the company's founders hope to offer licenses or subscriptions that translate to a cost of about $10 to $12 per test.

Nathaniel Hafer, a molecular biologist and testing expert at UMass Chan Medical School, said the test is "really fast and impressive," adding that expanding what types of samples can be used to detect Covid-19 is "really valuable. Not everybody can provide a nasal sample very easily."

Similarly, Cristina Davis, associate vice chancellor of interdisciplinary research and strategic initiatives at the University of California, Davis, called the test a "really exciting development for the entire field of breath analysis" and a "huge step forward."

"I'm excited we have another test in our [Covid-19] response toolbox," said Beth Linas, a research epidemiologist at RTI International. "I'm most pleased that this new test has a good negative predictive value, meaning people who receive a negative test are truly negative, because it gives us more confidence in identifying a positive coronavirus test as the prevalence of covid goes down."

However, Susan Butler-Wu, a clinical microbiologist at the Keck School of Medicine at the University of Southern California, said she'd like to see more independent data on how well the test performs, and more details on which VOCs it detects.

"The use of [VOCs] is not well developed for the diagnosis of infection," she said. "I would not feel comfortable using it for diagnosing patients without getting some more real-world data."

In addition, the machine that conducts these tests is relatively large—about the size of a carry-on suitcase—and must be used by trained operators supervised by health care professionals.

The test "looked good, not great, in terms of sensitivity," former FDA Commissioner Scott Gottlieb said. "So good enough as a belt-and-suspenders if you want to have an extra layer of protection at an event like the Gridiron dinner." (Diamond, Washington Post, 4/15; Santucci, USA Today, 4/15; Saric, Axios, 4/14; Associated Press, 4/14; Ingram, MedPage Today, 4/15; Anthes, New York Times, 4/15)