“…[ 11 , 55 , 57 ] Essentially, the instrument consists of head‐space sampling, sensor array, and pattern recognition modules, to generate signal patterns that are used for detecting the VOC fingerprint in disease. Haick and coworkers have developed chemiresistors based on monolayer‐capped metal nanoparticles or single‐wall carbon nanotubes to determine and classify a number of diseases from exhaled breath, including lung cancer [ 58 , 59 , 60 ] and gastric cancer [ 59 , 61 , 62 , 63 ] metabolic diseases as Crohn's disease, [ 64 ] ulcerative colitis, [ 64 ] irritable bowel syndrome, [ 65 ] and neurological diseases as idiopathic Parkinson, [ 64 , 66 ] atypical Parkinsonism, [ 64 , 66 , 67 ] multiple sclerosis, [ 68 , 69 ] as well as different infectious diseases including tuberculosis (TB) [ 70 ] and COVID‐19. [ 71 ] Using the same approach, they have shown that a breath‐based system can be used for diagnosis of infectious disease and pandemics.…”