3 links have been added on this idea.
  1. You can buy something similar! A company in the UK has a breath sampler, which collects exhaled air, which is then analyzed using medical machines for diagnosis. Hope they can sell breathalyzers that offer an instant diagnosis soon! In the meantime, you can order the sample here https://www.owlstonemedical.com/products/reciva/

  2. Scientists are researching the technology and reckon you can use it to diagnose several diseases at early stages, including cancer, TB, hypertension, neurological disorders, and more.

  3. Breath analysis can be a better and non-invasive diagnosis technique, replacing traditional blood and urine analysis. Check out this research paper which has more on the topic. https://www.embs.org/pulse/articles/the-great-exhale-using-breath-analysis-to-detect-disease/