This study uses the fenoTRACK device to measure Fractional Exhaled Nitric Oxide (FeNO) in people with asthma. FeNO is a gas found in your breath that helps doctors understand how well asthma is controlled. The study includes two groups: people with uncontrolled asthma and people with controlled asthma. For those with uncontrolled asthma, the study checks changes in FeNO after using corticosteroids (a type of medicine to reduce swelling) for 2 weeks. For controlled asthma, the study tests the accuracy of fenoTRACK when used at home versus in a clinic.

• The study lasts about 2 weeks and involves at least two visits.
• Participants will use the fenoTRACK device to measure FeNO at home and during visits.
• The study is looking for people aged 5 and above with asthma.

Participants should be aware that they need to follow study procedures and may not join if they have other major lung conditions or have recently taken certain medications. Pregnant or nursing individuals, and those with a significant smoking history, are not eligible.