Enlarge / Man entering a sample into the InspectIR COVID-19 breathalyzer.
Covid-19 Coverage
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The Food and Drug Administration on Thursday announced approval of the first breath-based test for COVID-19.
The InspectIR COVID-19 Breathalyzer provides highly accurate test results in approximately three minutes without the need for awkward swabs or the collection of dangerous samples. But before you get your hopes up for a portable device you can snort into when you step out, it’s not quite as convenient. The test requires a high-tech device the size of a carry-on—demo versions are literally housed in hard-shell trolley cases—and it requires a trained technician to operate it. To conduct the test, a person must sit next to the traveling instrument and blow into it through a straw for about 10 seconds.
The instrument in the luggage actually performs gas chromatography-mass spectrometry (GC-MS), a gold-standard analytical technique for finely separating the components of a mixture. In general, GC-MS samples are vaporized and mixed with an inert carrier gas before being passed through a capillary column that separates the components according to their boiling point and polarity. Then these components are ionized and fragmented and further separated by their mass-to-charge ratios. The final indication is various peaks on a gas chromatogram, each peak having a unique mass spectrum, allowing for the unequivocal identification of specific compounds.
For the COVID-19 breathalyser, InspectIR looks for the GC-MS signatures of five volatile organic compounds associated with SARS-CoV-2 infection. The recognition of these signatures has proven to be very accurate. According to the FDA, a study of 2,409 people found that the device correctly identified 91 percent of known positive samples as positive (test sensitivity) and 99 percent of known negative samples as negative (test specificity). The FDA also noted that known-positive samples came from people with and without COVID-19 symptoms and performed equally well in a follow-up study using the Omicron variant.
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Exhaling results
In addition, the study showed that the test can produce reliable negative results in populations with low infection rates. That means in a population where only 4.2 percent of people were infected, the test had a negative predictive value of almost 97 percent. However, the FDA warns that “negative results should be considered in the context of a patient’s recent exposures, history, and presence of clinical signs and symptoms consistent with COVID-19 as they indicate SARS-CoV-2 infection.” exclude and should not be used as the sole basis for treatment or patient management decisions, including infection control decisions.”
Enlarge / Touch screen display and keyboard of the test device.
The test’s maker, InspectIR Systems LLC, a Texas-based equipment company, reckons the breathalyzer could be rolled out to doctor’s offices, hospitals and mobile testing centers, where each instrument could perform about 160 tests per day. Because each breath sample is heated and ionized, there is no infectious or hazardous biological waste that needs to be cleaned or disposed of afterwards. Test takers only need a disposable hygienic straw for sample delivery.
But it’s unlikely to be showing up in every corner pharmacy anytime soon. InspectIR expects to be able to produce only about 100 instruments per week, the FDA notes. It’s also unclear how expensive each test will be at different sites.
Still, the portable mini-GC-MS is a more interesting—and potentially more accurate—rapid test for COVID-19 than the antigen-based methods that are currently in widespread use.
The FDA’s approval Thursday “is another example of rapid innovation in diagnostic tests for COVID-19,” Jeff Shuren, director of the FDA’s Center for Devices and Radiological Health, said in a statement. “The FDA continues to support the development of novel COVID-19 tests with the goal of advancing technologies that will help combat the current pandemic and better position the United States for the next public health emergency.”