The Food and Drug Administration, the U.S. food and drug regulatory agency, recently granted emergency clearance to a portable device that detects SARS-CoV-2 infections in just three minutes by analyzing breath covid positive people. InspectIR traces in the breath emitted by patients affected by the infection, the typical imprint of the new coronavirus, with a speed and accuracy that led some press organs to celebrate the end of the era of nasal swabs prematurely. But is it really so?
InspectIR: How it works. Many diseases cause physiological alterations in the compounds emitted through the breath, and some prototypes of anti-covid tests of this type are already used in several countries. InspectIR, designed by a small private company in Frisco (Texas), is the first to be authorized for sale in the USA. Using the gas chromatography-mass spectrometry technique, it analyzes the levels of five volatile organic compounds (substances present in the breath and produced by human metabolism) associated with SARS-CoV-2 infection. When InspectIR detects these markers – the manufacturers haven’t specified exactly which ones – it returns the response in three minutes presumptive positive: the diagnosis must still be confirmed with a molecular swab.
Accuracy. In company-sponsored clinical trials conducted on 2,409 asymptomatic patients, the breath test demonstrated a sensitivity 91%, ie correctly detected in over 9 cases out of 10 who then actually tested positive for the classic swab. There specificity instead it is 99%: it means that the probability of false positives is very low. However, the results will need to be verified in independent clinical studies.
Pros and cons. InspectIR could find interesting applications in contexts where multiple nasal swabs are required per day or where it is necessary to carry out mass screening in a short time, for example before concerts or sporting events, in airports, at the entrances of large companies or in newspapers. training of teams in professional sports.
But it also has several critical issues: it is very bulky (it is the size of a trolley) and despite its speed it can only process about twenty samples per hour. To use it on a large scale in 10-12 weeks, when it lands on the US market, production rates would have to be increased: at the moment we reach a hundred machines produced per week. Some substances ingested or smoked (such as tobacco) could skew the results, and the answer given is not exactly a diagnosis, but more a biochemical signature compatible with covid. Therefore, the spread of this test would not diminish the need for tampons, not yet ready to retire.