New breathalyser test can 'sniff out' Covid In real-time

Scientists have developed a new laser-based breathalyser test powered by artificial intelligence (AI) that they say can detect Covid-19 in real-time with excellent accuracy.

The team from the University of Colorado (CU) Boulder in the US hopes that the frequency comb breathalyser essentially using laser light to distinguish one molecule from another could revolutionise medical diagnostics.

"Our results demonstrate the promise of breath analysis as an alternative, rapid, non-invasive test for Covid-19 and highlight its remarkable potential for diagnosing diverse conditions and disease states," said study first author Qizhong Liang, a PhD candidate at CU Boulder.
"There is a real, foreseeable future in which you could go to the doctor and have your breath measured along with your height and weightÖOr you could blow into a mouthpiece integrated into your phone and get information about your health in real-time," said Jun Ye, adjoint professor at CU Boulder and senior author of the study published in the Journal of Breath Research.

Between May 2021 and January 2022, the research team collected breath samples from 170 CU Boulder students who had, in the previous 48 hours, taken a polymerase chain reaction (PCR) test, either by submitting a saliva or a nasal sample. Half had tested positive, half negative. Overall, the process took less than one hour from collection to result.

When compared to PCR, the gold standard Covid test, breathalyser results matched 85 per cent of the time. For medical diagnostics, accuracy of 80  per cent or greater is considered "excellent". The researchers noted that the accuracy would likely have been higher if the breath and saliva/nasal swab samples were collected at the same time.

Unlike a nasal swab, the breathalyser is non-invasive. And unlike a saliva sample, users are not asked to refrain from eating, drinking or smoking before using it, the researchers said. The test doesn't require costly chemicals to break down the sample. And the test could, conceivably, be used on individuals who are not conscious, they said.

The breathalyser test consists of a complex array of lasers and mirrors about the size of a banquet table. A breath sample is piped in through a tube as lasers fire invisible mid-infrared light at it at thousands of different frequencies. Dozens of tiny mirrors bounce the light back and forth through the molecules so many times that the light travels about 1.5 miles.

Because each kind of molecule absorbs light differently, breath samples with a different molecular make-up cast distinct shadows. The machine can distinguish between those different shadows or absorption patterns, boiling millions of data points down toóin the case of COVID a simple positive or negative, in a matter of  seconds.The researchers are working to miniaturise such systems to a chip scale, allowing for what Liang imagines as "real-time, self-health monitoring on the go".